Asynchronous RPC support (#2017)

* Async RPC * Limiting number of transactions in queue * Fixing tests * Bumping serde and jsonrpc-core * serde updated to 0.8 * fixed failing tests * Bumping ipc server * Fixing API for endpoints * Experimenting with tests without --release mode
2016-09-01 12:00:00 +02:00 · 2016-09-01 12:00:00 +02:00 · b4f3c4bd7a
parent ca03cfa58a
commit b4f3c4bd7a
43 changed files with 657 additions and 515 deletions
--- a/.travis.yml
+++ b/.travis.yml
@ -16,7 +16,7 @@ git:
 matrix:
  include:
  - rust: stable
-    env: RUN_TESTS="true"
+    env: RUN_TESTS="true" TEST_OPTIONS="--no-release"
  - rust: beta
    env: RUN_COVERAGE="true"
  - rust: stable
@ -30,6 +30,7 @@ env:
  - RUN_TESTS="false"
  - RUN_COVERAGE="false"
  - RUN_DOCS="false"
+  - TEST_OPTIONS=""
  # GH_TOKEN for documentation
  - secure: 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
  - KCOV_CMD="./kcov-master/tmp/usr/local/bin/kcov"
@ -64,7 +65,7 @@ install:
    )

 script:
-  - if [ "$RUN_TESTS" = "true" ]; then ./test.sh --verbose; fi
+  - if [ "$RUN_TESTS" = "true" ]; then ./test.sh $TEST_OPTIONS --verbose; fi
  - if [ "$RUN_COVERAGE" = "true" ]; then ./scripts/cov.sh "$KCOV_CMD"; fi

 after_success: |
--- a/Cargo.lock
+++ b/Cargo.lock
@ -70,6 +70,14 @@ dependencies = [
 "syntex_syntax 0.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

+[[package]]
+name = "aster"
+version = "0.25.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "syntex_syntax 0.42.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "bigint"
 version = "0.1.0"
@ -173,7 +181,7 @@ version = "1.1.1"
 source = "git+https://github.com/ethcore/rust-ctrlc.git#f4927770f89eca80ec250911eea3adcbf579ac48"
 dependencies = [
 "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "winapi 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@ -182,7 +190,7 @@ name = "daemonize"
 version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@ -203,6 +211,11 @@ dependencies = [
 "strsim 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

+[[package]]
+name = "dtoa"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "elastic-array"
 version = "0.4.0"
@ -224,21 +237,21 @@ source = "git+https://github.com/ethcore/rust-secp256k1#a9a0b1be1f39560ca86e8fc8
 dependencies = [
 "arrayvec 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
 "gcc 0.3.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
 name = "ethabi"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "docopt 0.6.80 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_codegen 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_codegen 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "tiny-keccak 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@ -289,11 +302,11 @@ name = "ethcore-dapps"
 version = "1.4.0"
 dependencies = [
 "clippy 0.0.85 (registry+https://github.com/rust-lang/crates.io-index)",
- "ethabi 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ethabi 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "ethcore-rpc 1.4.0",
 "ethcore-util 1.4.0",
 "hyper 0.9.4 (git+https://github.com/ethcore/hyper)",
- "jsonrpc-core 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "jsonrpc-http-server 6.1.0 (git+https://github.com/ethcore/jsonrpc-http-server.git)",
 "linked-hash-map 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
@ -304,9 +317,9 @@ dependencies = [
 "parity-dapps-wallet 1.4.0 (git+https://github.com/ethcore/parity-ui.git)",
 "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_codegen 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_codegen 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "unicase 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "zip 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
@ -410,7 +423,7 @@ dependencies = [
 "ethcrypto 0.1.0",
 "ethkey 0.2.0",
 "igd 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "mio 0.5.1 (git+https://github.com/ethcore/mio?branch=v0.5.x)",
 "parking_lot 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
@ -438,13 +451,13 @@ dependencies = [
 "ethstore 0.1.0",
 "ethsync 1.4.0",
 "json-ipc-server 0.2.4 (git+https://github.com/ethcore/json-ipc-server.git)",
- "jsonrpc-core 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "jsonrpc-http-server 6.1.0 (git+https://github.com/ethcore/jsonrpc-http-server.git)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_codegen 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_codegen 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
 "transient-hashmap 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -458,7 +471,7 @@ dependencies = [
 "ethcore-io 1.4.0",
 "ethcore-rpc 1.4.0",
 "ethcore-util 1.4.0",
- "jsonrpc-core 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "parity-dapps-signer 1.4.0 (git+https://github.com/ethcore/parity-ui.git)",
 "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
@ -477,7 +490,7 @@ dependencies = [
 "ethcore-ipc-nano 1.4.0",
 "ethcore-util 1.4.0",
 "json-tcp-server 0.1.0 (git+https://github.com/ethcore/json-tcp-server)",
- "jsonrpc-core 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "mio 0.5.1 (git+https://github.com/ethcore/mio?branch=v0.5.x)",
@ -499,7 +512,7 @@ dependencies = [
 "heapsize 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "itertools 0.4.13 (registry+https://github.com/rust-lang/crates.io-index)",
 "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
@ -533,9 +546,9 @@ version = "0.1.0"
 dependencies = [
 "ethcore-util 1.4.0",
 "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_codegen 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_codegen 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@ -558,13 +571,13 @@ dependencies = [
 "ethkey 0.2.0",
 "itertools 0.4.13 (registry+https://github.com/rust-lang/crates.io-index)",
 "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
 "rust-crypto 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_codegen 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_codegen 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
 "tiny-keccak 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -594,7 +607,7 @@ dependencies = [
 name = "fdlimit"
 version = "0.1.0"
 dependencies = [
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@ -602,7 +615,7 @@ name = "flate2"
 version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "miniz-sys 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@ -711,7 +724,7 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "winapi 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@ -720,14 +733,19 @@ name = "itertools"
 version = "0.4.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"

+[[package]]
+name = "itoa"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "json-ipc-server"
 version = "0.2.4"
-source = "git+https://github.com/ethcore/json-ipc-server.git#56b6307130710ebc73cb9be087b6ed0b6c400bcf"
+source = "git+https://github.com/ethcore/json-ipc-server.git#5fbd0253750d3097b9a8fb27effa84c18d630bbb"
 dependencies = [
 "bytes 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "env_logger 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "mio 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
@ -738,11 +756,11 @@ dependencies = [
 [[package]]
 name = "json-tcp-server"
 version = "0.1.0"
-source = "git+https://github.com/ethcore/json-tcp-server#05c186ea100e2107c1f9f83ca4c62cb6ed2c68bd"
+source = "git+https://github.com/ethcore/json-tcp-server#c2858522274ae56042472bb5d22845a1b85e5338"
 dependencies = [
 "bytes 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "env_logger 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "mio 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
@ -751,22 +769,24 @@ dependencies = [

 [[package]]
 name = "jsonrpc-core"
-version = "2.1.1"
+version = "3.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_codegen 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_codegen 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
 name = "jsonrpc-http-server"
 version = "6.1.0"
-source = "git+https://github.com/ethcore/jsonrpc-http-server.git#4e3f93eb79125e91a46e04d77c25ff8885498b86"
+source = "git+https://github.com/ethcore/jsonrpc-http-server.git#339f7209b01d26aea01722b3a69127235287d6a9"
 dependencies = [
 "hyper 0.9.4 (git+https://github.com/ethcore/hyper)",
- "jsonrpc-core 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "unicase 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@ -791,7 +811,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"

 [[package]]
 name = "libc"
-version = "0.2.12"
+version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"

 [[package]]
@ -814,7 +834,7 @@ name = "memchr"
 version = "0.1.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@ -842,7 +862,7 @@ version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "gcc 0.3.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@ -851,7 +871,7 @@ version = "0.5.1"
 source = "git+https://github.com/ethcore/mio?branch=v0.5.x#3842d3b250ffd7bd9b16f9586b875ddcbac2b0dd"
 dependencies = [
 "bytes 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "miow 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "net2 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
@ -867,7 +887,7 @@ version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "bytes 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "miow 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "net2 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
@ -883,7 +903,7 @@ version = "0.6.0-dev"
 source = "git+https://github.com/carllerche/mio?rev=62ec763c9cc34d8a452ed0392c575c50ddd5fc8d#62ec763c9cc34d8a452ed0392c575c50ddd5fc8d"
 dependencies = [
 "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "miow 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
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 "checksum primal-estimate 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "56ea4531dde757b56906493c8604641da14607bf9cdaa80fb9c9cabd2429f8d5"
 "checksum primal-sieve 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "7aa73fd87e5984a00bdb4c1b14d3d5d6d0bad01b2caaaf924c16ab7260ac946c"
 "checksum quasi 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b26543b563704e7d87f3ec7cfafb713010a905c5f1b155a8ab66863af43ca578"
+"checksum quasi 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)" = "cb7eaef226a434a570fa336bc99502c4f5878208c1ebdd83b2d0bc37b1b1c34c"
 "checksum quasi_codegen 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0881d9a45d5f9ebe4a7e77742f8c604f3658c212baf8dd711a692dd000bc648c"
+"checksum quasi_codegen 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)" = "62e90381b315dfd00bfe6efbfeeec9f03a6d66159c3a5c8411b6c550d24b08fd"
 "checksum quick-error 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0aad603e8d7fb67da22dbdf1f4b826ce8829e406124109e73cf1b2454b93a71c"
 "checksum quine-mc_cluskey 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a6683b0e23d80813b1a535841f0048c1537d3f86d63c999e8373b39a9b0eb74a"
 "checksum rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)" = "2791d88c6defac799c3f20d74f094ca33b9332612d9aef9078519c82e4fe04a5"
@ -1767,9 +1878,10 @@ dependencies = [
 "checksum rustc_version 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "c5f5376ea5e30ce23c03eb77cbe4962b988deead10910c372b226388b594c084"
 "checksum semver 0.1.20 (registry+https://github.com/rust-lang/crates.io-index)" = "d4f410fedcf71af0345d7607d246e7ad15faaadd49d240ee3b24e5dc21a820ac"
 "checksum semver 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2d5b7638a1f03815d94e88cb3b3c08e87f0db4d683ef499d1836aaf70a45623f"
-"checksum serde 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)" = "b76133a8a02f1c6ebd3fb9a2ecaab3d54302565a51320e80931adba571aadb1b"
-"checksum serde_codegen 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)" = "c5b74ff4fb34013cc0b917dd182fefc05ee9af233b9d0d557078334554284d0e"
-"checksum serde_json 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2c88a751caa8f0000058fb971cd443ed2e6b653f33f5a47f29892a8bd44ca4c1"
+"checksum serde 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)" = "b1dfda9ebb31d29fa8b94d7eb3031a86a8dcec065f0fe268a30f98867bf45775"
+"checksum serde_codegen 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)" = "e422ae53d7933f59c6ff57e7b5870b5c9094b1f473f78ec33d89f8a692c3ec02"
+"checksum serde_codegen_internals 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f877e2781ed0a323295d1c9f0e26556117b5a11489fc47b1848dfb98b3173d21"
+"checksum serde_json 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0e10f8a9d94b06cf5d3bef66475f04c8ff90950f1be7004c357ff9472ccbaebc"
 "checksum sha1 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "cc30b1e1e8c40c121ca33b86c23308a090d19974ef001b4bf6e61fd1a0fb095c"
 "checksum slab 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "d807fd58c4181bbabed77cb3b891ba9748241a552bcc5be698faaebefc54f46e"
 "checksum slab 0.2.0 (git+https://github.com/carllerche/slab?rev=5476efcafb)" = "<none>"
@ -1780,9 +1892,14 @@ dependencies = [
 "checksum stable-heap 0.1.0 (git+https://github.com/carllerche/stable-heap?rev=3c5cd1ca47)" = "<none>"
 "checksum strsim 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e4d73a2c36a4d095ed1a6df5cbeac159863173447f7a82b3f4757426844ab825"
 "checksum syntex 0.33.0 (registry+https://github.com/rust-lang/crates.io-index)" = "393b6dd0889df2b064beeea954cfda6bc2571604ac460deeae0fed55a53988af"
+"checksum syntex 0.42.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0a30b08a6b383a22e5f6edc127d169670d48f905bb00ca79a00ea3e442ebe317"
+"checksum syntex_errors 0.42.0 (registry+https://github.com/rust-lang/crates.io-index)" = "04c48f32867b6114449155b2a82114b86d4b09e1bddb21c47ff104ab9172b646"
+"checksum syntex_pos 0.42.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3fd49988e52451813c61fecbe9abb5cfd4e1b7bb6cdbb980a6fbcbab859171a6"
 "checksum syntex_syntax 0.33.0 (registry+https://github.com/rust-lang/crates.io-index)" = "44bded3cabafc65c90b663b1071bd2d198a9ab7515e6ce729e4570aaf53c407e"
+"checksum syntex_syntax 0.42.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7628a0506e8f9666fdabb5f265d0059b059edac9a3f810bda077abb5d826bd8d"
 "checksum target_info 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c63f48baada5c52e65a29eef93ab4f8982681b67f9e8d29c7b05abcfec2b9ffe"
 "checksum term 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)" = "f2077e54d38055cf1ca0fd7933a2e00cd3ec8f6fed352b2a377f06dcdaaf3281"
+"checksum term 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "3deff8a2b3b6607d6d7cc32ac25c0b33709453ca9cceac006caac51e963cf94a"
 "checksum termios 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d5d9cf598a6d7ce700a4e6a9199da127e6819a61e64b68609683cc9a01b5683a"
 "checksum thread-id 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a9539db560102d1cef46b8b78ce737ff0bb64e7e18d35b2a5688f7d097d0ff03"
 "checksum thread_local 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "0694f51610ef7cfac7a1b81de7f1602ee5356e76541bcd62c40e71933338cab1"
--- a/dapps/Cargo.toml
+++ b/dapps/Cargo.toml
@ -11,17 +11,17 @@ build = "build.rs"
 [dependencies]
 rand = "0.3.14"
 log = "0.3"
-jsonrpc-core = "2.1"
+jsonrpc-core = "3.0"
 jsonrpc-http-server = { git = "https://github.com/ethcore/jsonrpc-http-server.git" }
 hyper = { default-features = false, git = "https://github.com/ethcore/hyper" }
 unicase = "1.3"
 url = "1.0"
 rustc-serialize = "0.3"
-serde = "0.7.0"
-serde_json = "0.7.0"
-serde_macros = { version = "0.7.0", optional = true }
+serde = "0.8"
+serde_json = "0.8"
+serde_macros = { version = "0.8", optional = true }
 zip = { version = "0.1", default-features = false }
-ethabi = "0.2.1"
+ethabi = "0.2.2"
 linked-hash-map = "0.3"
 ethcore-rpc = { path = "../rpc" }
 ethcore-util = { path = "../util" }
@ -34,7 +34,7 @@ mime_guess = { version = "1.6.1" }
 clippy = { version = "0.0.85", optional = true}

 [build-dependencies]
-serde_codegen = { version = "0.7.0", optional = true }
+serde_codegen = { version = "0.8", optional = true }

 [features]
 default = ["serde_codegen", "extra-dapps"]
--- a/dapps/src/apps/fetcher.rs
+++ b/dapps/src/apps/fetcher.rs
@ -26,7 +26,7 @@ use std::sync::Arc;
 use std::sync::atomic::{AtomicBool};
 use rustc_serialize::hex::FromHex;

-use hyper::Control;
+use hyper;
 use hyper::status::StatusCode;

 use random_filename;
@ -85,7 +85,7 @@ impl<R: URLHint> AppFetcher<R> {
 		}
 	}

-	pub fn to_handler(&self, path: EndpointPath, control: Control) -> Box<Handler> {
+	pub fn to_async_handler(&self, path: EndpointPath, control: hyper::Control) -> Box<Handler> {
 		let mut dapps = self.dapps.lock();
 		let app_id = path.app_id.clone();

@ -94,7 +94,7 @@ impl<R: URLHint> AppFetcher<R> {
 			match status {
 				// Just server dapp
 				Some(&mut ContentStatus::Ready(ref endpoint)) => {
-					(None, endpoint.to_handler(path))
+					(None, endpoint.to_async_handler(path, control))
 				},
 				// App is already being fetched
 				Some(&mut ContentStatus::Fetching(_)) => {
--- a/dapps/src/endpoint.rs
+++ b/dapps/src/endpoint.rs
@ -16,7 +16,7 @@

 //! URL Endpoint traits

-use hyper::{server, net};
+use hyper::{self, server, net};
 use std::collections::BTreeMap;

 #[derive(Debug, PartialEq, Default, Clone)]
@ -43,4 +43,8 @@ pub trait Endpoint : Send + Sync {
 	fn info(&self) -> Option<&EndpointInfo> { None }

 	fn to_handler(&self, path: EndpointPath) -> Box<Handler>;
+
+	fn to_async_handler(&self, path: EndpointPath, _control: hyper::Control) -> Box<Handler> {
+		self.to_handler(path)
+	}
 }
--- a/dapps/src/router/mod.rs
+++ b/dapps/src/router/mod.rs
@ -73,20 +73,20 @@ impl<A: Authorization + 'static> server::Handler<HttpStream> for Router<A> {
 		// Choose proper handler depending on path / domain
 		let url = extract_url(&req);
 		let endpoint = extract_endpoint(&url);
+		let control = self.control.take().expect("on_request is called only once; control is always defined at start; qed");

 		self.handler = match endpoint {
 			// First check special endpoints
 			(ref path, ref endpoint) if self.special.contains_key(endpoint) => {
-				self.special.get(endpoint).unwrap().to_handler(path.clone().unwrap_or_default())
+				self.special.get(endpoint).unwrap().to_async_handler(path.clone().unwrap_or_default(), control)
 			},
 			// Then delegate to dapp
 			(Some(ref path), _) if self.endpoints.contains_key(&path.app_id) => {
-				self.endpoints.get(&path.app_id).unwrap().to_handler(path.clone())
+				self.endpoints.get(&path.app_id).unwrap().to_async_handler(path.clone(), control)
 			},
 			// Try to resolve and fetch the dapp
 			(Some(ref path), _) if self.fetch.contains(&path.app_id) => {
-				let control = self.control.take().expect("on_request is called only once, thus control is always defined.");
-				self.fetch.to_handler(path.clone(), control)
+				self.fetch.to_async_handler(path.clone(), control)
 			},
 			// Redirection to main page (maybe 404 instead?)
 			(Some(ref path), _) if *req.method() == hyper::method::Method::Get => {
@ -100,7 +100,7 @@ impl<A: Authorization + 'static> server::Handler<HttpStream> for Router<A> {
 			},
 			// RPC by default
 			_ => {
-				self.special.get(&SpecialEndpoint::Rpc).unwrap().to_handler(EndpointPath::default())
+				self.special.get(&SpecialEndpoint::Rpc).unwrap().to_async_handler(EndpointPath::default(), control)
 			}
 		};

@ -135,7 +135,7 @@ impl<A: Authorization> Router<A> {
 		allowed_hosts: Option<Vec<String>>,
 		) -> Self {

-		let handler = special.get(&SpecialEndpoint::Rpc).unwrap().to_handler(EndpointPath::default());
+		let handler = special.get(&SpecialEndpoint::Api).unwrap().to_handler(EndpointPath::default());
 		Router {
 			control: Some(control),
 			main_page: main_page,
--- a/dapps/src/rpc.rs
+++ b/dapps/src/rpc.rs
@ -15,6 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.

 use std::sync::{Arc, Mutex};
+use hyper;
 use jsonrpc_core::IoHandler;
 use jsonrpc_http_server::{ServerHandler, PanicHandler, AccessControlAllowOrigin};
 use endpoint::{Endpoint, EndpointPath, Handler};
@ -38,7 +39,17 @@ struct RpcEndpoint {

 impl Endpoint for RpcEndpoint {
 	fn to_handler(&self, _path: EndpointPath) -> Box<Handler> {
+		panic!("RPC Endpoint is asynchronous and requires Control object.");
+	}
+
+	fn to_async_handler(&self, _path: EndpointPath, control: hyper::Control) -> Box<Handler> {
 		let panic_handler = PanicHandler { handler: self.panic_handler.clone() };
-		Box::new(ServerHandler::new(self.handler.clone(), self.cors_domain.clone(), self.allowed_hosts.clone(), panic_handler))
+		Box::new(ServerHandler::new(
+				self.handler.clone(),
+				self.cors_domain.clone(),
+				self.allowed_hosts.clone(),
+				panic_handler,
+				control,
+		))
 	}
 }
--- a/ethstore/Cargo.toml
+++ b/ethstore/Cargo.toml
@ -8,9 +8,9 @@ build = "build.rs"
 libc = "0.2.11"
 rand = "0.3.14"
 ethkey = { path = "../ethkey" }
-serde = "0.7"
-serde_json = "0.7"
-serde_macros = { version = "0.7", optional = true }
+serde = "0.8"
+serde_json = "0.8"
+serde_macros = { version = "0.8", optional = true }
 rustc-serialize = "0.3"
 rust-crypto = "0.2.36"
 tiny-keccak = "1.0"
@ -21,7 +21,7 @@ itertools = "0.4"
 ethcrypto = { path = "../ethcrypto" }

 [build-dependencies]
-serde_codegen = { version = "0.7", optional = true }
+serde_codegen = { version = "0.8", optional = true }

 [features]
 default = ["serde_codegen"]
--- a/ethstore/src/json/crypto.rs
+++ b/ethstore/src/json/crypto.rs
@ -16,7 +16,6 @@

 use serde::{Deserialize, Deserializer, Serialize, Serializer, Error};
 use serde::de::{Visitor, MapVisitor};
-use serde::ser;
 use super::{Cipher, CipherSer, CipherSerParams, Kdf, KdfSer, KdfSerParams, H256};

 #[derive(Debug, PartialEq)]
@ -141,60 +140,26 @@ impl Serialize for Crypto {
 	fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
 		where S: Serializer
 	{
-		serializer.serialize_struct("Crypto", CryptoMapVisitor {
-			value: self,
-			state: 0,
-		})
-	}
-}
-
-struct CryptoMapVisitor<'a> {
-	value: &'a Crypto,
-	state: u8,
-}
-
-impl<'a> ser::MapVisitor for CryptoMapVisitor<'a> {
-	fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
-		where S: Serializer
-	{
-		match self.state {
-			0 => {
-				self.state += 1;
-				match self.value.cipher {
-					Cipher::Aes128Ctr(_) => Ok(Some(try!(serializer.serialize_struct_elt("cipher", &CipherSer::Aes128Ctr)))),
-				}
+		let mut state = try!(serializer.serialize_struct("Crypto", 6));
+		match self.cipher {
+			Cipher::Aes128Ctr(ref params) => {
+				try!(serializer.serialize_struct_elt(&mut state, "cipher", &CipherSer::Aes128Ctr));
+				try!(serializer.serialize_struct_elt(&mut state, "cipherparams", params));
 			},
-			1 => {
-				self.state += 1;
-				match self.value.cipher {
-					Cipher::Aes128Ctr(ref params) => Ok(Some(try!(serializer.serialize_struct_elt("cipherparams", params)))),
-				}
-			},
-			2 => {
-				self.state += 1;
-				Ok(Some(try!(serializer.serialize_struct_elt("ciphertext", &self.value.ciphertext))))
-			},
-			3 => {
-				self.state += 1;
-				match self.value.kdf {
-					Kdf::Pbkdf2(_) => Ok(Some(try!(serializer.serialize_struct_elt("kdf", &KdfSer::Pbkdf2)))),
-					Kdf::Scrypt(_) => Ok(Some(try!(serializer.serialize_struct_elt("kdf", &KdfSer::Scrypt)))),
-				}
-			},
-			4 => {
-				self.state += 1;
-				match self.value.kdf {
-					Kdf::Pbkdf2(ref params) => Ok(Some(try!(serializer.serialize_struct_elt("kdfparams", params)))),
-					Kdf::Scrypt(ref params) => Ok(Some(try!(serializer.serialize_struct_elt("kdfparams", params)))),
-				}
-			},
-			5 => {
-				self.state += 1;
-				Ok(Some(try!(serializer.serialize_struct_elt("mac", &self.value.mac))))
-			},
-			_ => {
-				Ok(None)
-			}
 		}
+		try!(serializer.serialize_struct_elt(&mut state, "ciphertext", &self.ciphertext));
+		match self.kdf {
+			Kdf::Pbkdf2(ref params) => {
+				try!(serializer.serialize_struct_elt(&mut state, "kdf", &KdfSer::Pbkdf2));
+				try!(serializer.serialize_struct_elt(&mut state, "kdfparams", params));
+			},
+			Kdf::Scrypt(ref params) => {
+				try!(serializer.serialize_struct_elt(&mut state, "kdf", &KdfSer::Scrypt));
+				try!(serializer.serialize_struct_elt(&mut state, "kdfparams", params));
+			},
+		}
+
+		try!(serializer.serialize_struct_elt(&mut state, "mac", &self.mac));
+		serializer.serialize_struct_end(state)
 	}
 }
--- a/json/Cargo.toml
+++ b/json/Cargo.toml
@ -7,13 +7,13 @@ build = "build.rs"
 [dependencies]
 ethcore-util = { path = "../util" }
 rustc-serialize = "0.3"
-serde = "0.7.0"
-serde_json = "0.7.0"
-serde_macros = { version = "0.7.0", optional = true }
+serde = "0.8"
+serde_json = "0.8"
+serde_macros = { version = "0.8", optional = true }
 clippy = { version = "0.0.85", optional = true}

 [build-dependencies]
-serde_codegen = { version = "0.7.0", optional = true }
+serde_codegen = { version = "0.8", optional = true }

 [features]
 default = ["serde_codegen"]
--- a/json/src/blockchain/blockchain.rs
+++ b/json/src/blockchain/blockchain.rs
@ -178,5 +178,5 @@ mod tests {
 		}"#;
 		let _deserialized: BlockChain = serde_json::from_str(s).unwrap();
 		// TODO: validate all fields
-	//}
+	}
 }
--- a/json/src/bytes.rs
+++ b/json/src/bytes.rs
@ -56,7 +56,7 @@ impl FromStr for Bytes {
 			2 if value.starts_with("0x") => vec![],
 			_ if value.starts_with("0x") && value.len() % 2 == 1 => {
 				let v = "0".to_owned() + &value[2..];
-				FromHex::from_hex(v.as_ref() as &str).unwrap_or(vec![]),
+				FromHex::from_hex(v.as_str()).unwrap_or(vec![])
 			},
 			_ if value.starts_with("0x") => FromHex::from_hex(&value[2..]).unwrap_or(vec![]),
 			_ => FromHex::from_hex(value).unwrap_or(vec![]),
--- a/json/src/vm/call.rs
+++ b/json/src/vm/call.rs
@ -39,9 +39,8 @@ pub struct Call {
 mod tests {
 	use serde_json;
 	use vm::Call;
-	use util::U256;
+	use util::{U256, H160 as Hash160};
 	use uint::Uint;
-	use util::hash::Address as Hash160;
 	use hash::Address;
 	use maybe::MaybeEmpty;
 	use std::str::FromStr;
--- a/rpc/Cargo.toml
+++ b/rpc/Cargo.toml
@ -10,9 +10,9 @@ build = "build.rs"

 [dependencies]
 log = "0.3"
-serde = "0.7.0"
-serde_json = "0.7.0"
-jsonrpc-core = "2.1"
+serde = "0.8"
+serde_json = "0.8"
+jsonrpc-core = "3.0"
 jsonrpc-http-server = { git = "https://github.com/ethcore/jsonrpc-http-server.git" }
 ethcore-io = { path = "../util/io" }
 ethcore-util = { path = "../util" }
@ -25,14 +25,14 @@ ethjson = { path = "../json" }
 ethcore-devtools = { path = "../devtools" }
 rustc-serialize = "0.3"
 transient-hashmap = "0.1"
-serde_macros = { version = "0.7.0", optional = true }
+serde_macros = { version = "0.8.0", optional = true }
 clippy = { version = "0.0.85", optional = true}
 json-ipc-server = { git = "https://github.com/ethcore/json-ipc-server.git" }
 ethcore-ipc = { path = "../ipc/rpc" }
 time = "0.1"

 [build-dependencies]
-serde_codegen = { version = "0.7.0", optional = true }
+serde_codegen = { version = "0.8.0", optional = true }

 [features]
 default = ["serde_codegen"]
--- a/rpc/src/v1/helpers/dispatch.rs
+++ b/rpc/src/v1/helpers/dispatch.rs
@ -50,13 +50,13 @@ pub fn dispatch_transaction<C, M>(client: &C, miner: &M, signed_transaction: Sig

 	import
 		.map_err(errors::from_transaction_error)
-		.and_then(|_| to_value(&hash))
+		.map(|_| to_value(&hash))
 }

 pub fn signature_with_password(accounts: &AccountProvider, address: Address, hash: H256, pass: String) -> Result<Value, Error> {
 	accounts.sign_with_password(address, pass, hash)
 		.map_err(errors::from_password_error)
-		.and_then(|hash| to_value(&RpcH520::from(hash)))
+		.map(|hash| to_value(&RpcH520::from(hash)))
 }

 pub fn unlock_sign_and_dispatch<C, M>(client: &C, miner: &M, request: TransactionRequest, account_provider: &AccountProvider, password: String) -> Result<Value, Error>
--- a/rpc/src/v1/helpers/errors.rs
+++ b/rpc/src/v1/helpers/errors.rs
@ -38,7 +38,8 @@ mod codes {
 	pub const ACCOUNT_ERROR: i64 = -32023;
 	pub const SIGNER_DISABLED: i64 = -32030;
 	pub const REQUEST_REJECTED: i64 = -32040;
-	pub const REQUEST_NOT_FOUND: i64 = -32041;
+	pub const REQUEST_REJECTED_LIMIT: i64 = -32041;
+	pub const REQUEST_NOT_FOUND: i64 = -32042;
 	pub const COMPILATION_ERROR: i64 = -32050;
 }

@ -66,6 +67,13 @@ pub fn request_rejected() -> Error {
 	}
 }

+pub fn request_rejected_limit() -> Error {
+	Error {
+		code: ErrorCode::ServerError(codes::REQUEST_REJECTED_LIMIT),
+		message: "Request has been rejected because of queue limit.".into(),
+		data: None,
+	}
+}

 pub fn account<T: fmt::Debug>(error: &str, details: T) -> Error {
 	Error {
--- a/rpc/src/v1/helpers/signing_queue.rs
+++ b/rpc/src/v1/helpers/signing_queue.rs
@ -14,8 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.

-use std::thread;
-use std::time::{Instant, Duration};
+use std::mem;
+use std::cell::RefCell;
 use std::sync::{mpsc, Arc};
 use std::collections::BTreeMap;
 use jsonrpc_core;
@ -47,14 +47,23 @@ pub enum QueueError {
 	ReceiverError(mpsc::RecvError),
 }

+/// Defines possible errors when inserting to queue
+#[derive(Debug, PartialEq)]
+pub enum QueueAddError {
+	LimitReached,
+}
+
 /// Message Receiver type
 pub type QueueEventReceiver = mpsc::Receiver<QueueEvent>;

+// TODO [todr] to consider: timeout instead of limit?
+const QUEUE_LIMIT: usize = 50;
+
 /// A queue of transactions awaiting to be confirmed and signed.
 pub trait SigningQueue: Send + Sync {
 	/// Add new request to the queue.
 	/// Returns a `ConfirmationPromise` that can be used to await for resolution of given request.
-	fn add_request(&self, request: ConfirmationPayload) -> ConfirmationPromise;
+	fn add_request(&self, request: ConfirmationPayload) -> Result<ConfirmationPromise, QueueAddError>;

 	/// Removes a request from the queue.
 	/// Notifies possible token holders that request was rejected.
@ -88,42 +97,45 @@ pub enum ConfirmationResult {
 	Confirmed(RpcResult),
 }

-/// Time you need to confirm the request in UI.
-/// This is the amount of time token holder will wait before
-/// returning `None`.
-/// Unless we have a multi-threaded RPC this will lock
-/// any other incoming call!
-const QUEUE_TIMEOUT_DURATION_SEC : u64 = 20;
+type Listener = Box<FnMut(Option<RpcResult>) + Send>;

 /// A handle to submitted request.
 /// Allows to block and wait for a resolution of that request.
 pub struct ConfirmationToken {
 	result: Arc<Mutex<ConfirmationResult>>,
-	handle: thread::Thread,
+	listeners: Arc<Mutex<Vec<Listener>>>,
 	request: ConfirmationRequest,
-	timeout: Duration,
 }

 pub struct ConfirmationPromise {
 	id: U256,
 	result: Arc<Mutex<ConfirmationResult>>,
-	timeout: Duration,
+	listeners: Arc<Mutex<Vec<Listener>>>,
 }

 impl ConfirmationToken {
 	/// Submit solution to all listeners
 	fn resolve(&self, result: Option<RpcResult>) {
-		let mut res = self.result.lock();
-		*res = result.map_or(ConfirmationResult::Rejected, |h| ConfirmationResult::Confirmed(h));
+		let wrapped = result.clone().map_or(ConfirmationResult::Rejected, |h| ConfirmationResult::Confirmed(h));
+		{
+			let mut res = self.result.lock();
+			*res = wrapped.clone();
+		}
 		// Notify listener
-		self.handle.unpark();
+		let listeners = {
+			let mut listeners = self.listeners.lock();
+			mem::replace(&mut *listeners, Vec::new())
+		};
+		for mut listener in listeners {
+			listener(result.clone());
+		}
 	}

 	fn as_promise(&self) -> ConfirmationPromise {
 		ConfirmationPromise {
 			id: self.request.id,
 			result: self.result.clone(),
-			timeout: self.timeout,
+			listeners: self.listeners.clone(),
 		}
 	}
 }
@ -132,49 +144,31 @@ impl ConfirmationPromise {
 	/// Get the ID for this request.
 	pub fn id(&self) -> U256 { self.id }

-	/// Blocks current thread and awaits for
-	/// resolution of the transaction (rejected / confirmed)
-	/// Returns `None` if transaction was rejected or timeout reached.
-	/// Returns `Some(result)` if transaction was confirmed.
-	pub fn wait_with_timeout(&self) -> Option<RpcResult> {
-		let res = self.wait_until(Instant::now() + self.timeout);
-		match res {
-			ConfirmationResult::Confirmed(h) => Some(h),
-			ConfirmationResult::Rejected | ConfirmationResult::Waiting => None,
-		}
+	/// Just get the result, assuming it exists.
+	pub fn result(&self) -> ConfirmationResult {
+		self.result.lock().clone()
 	}

-	/// Just get the result, assuming it exists.
-	pub fn result(&self) -> ConfirmationResult { self.wait_until(Instant::now()) }
-
-	/// Blocks current thread and awaits for
-	/// resolution of the request (rejected / confirmed)
-	/// Returns `None` if request was rejected or timeout reached.
-	/// Returns `Some(result)` if request was confirmed.
-	pub fn wait_until(&self, deadline: Instant) -> ConfirmationResult {
+	pub fn wait_for_result<F>(self, callback: F) where F: FnOnce(Option<RpcResult>) + Send + 'static {
 		trace!(target: "own_tx", "Signer: Awaiting confirmation... ({:?}).", self.id);
-		loop {
-			let now = Instant::now();
-			// Check the result...
-			match *self.result.lock() {
-				// Waiting and deadline not yet passed continue looping.
-				ConfirmationResult::Waiting if now < deadline => {}
-				// Anything else - return.
-				ref a => return a.clone(),
-			}
-			// wait a while longer - maybe the solution will arrive.
-			thread::park_timeout(deadline - now);
-		}
+		let _result = self.result.lock();
+		let mut listeners = self.listeners.lock();
+		// TODO [todr] Overcoming FnBox unstability
+		let callback = RefCell::new(Some(callback));
+		listeners.push(Box::new(move |result| {
+			let ref mut f = *callback.borrow_mut();
+			f.take().expect("Callbacks are called only once.")(result)
+		}));
 	}
 }

+
 /// Queue for all unconfirmed requests.
 pub struct ConfirmationsQueue {
 	id: Mutex<U256>,
 	queue: RwLock<BTreeMap<U256, ConfirmationToken>>,
 	sender: Mutex<mpsc::Sender<QueueEvent>>,
 	receiver: Mutex<Option<mpsc::Receiver<QueueEvent>>>,
-	timeout: Duration,
 }

 impl Default for ConfirmationsQueue {
@ -186,19 +180,11 @@ impl Default for ConfirmationsQueue {
 			queue: RwLock::new(BTreeMap::new()),
 			sender: Mutex::new(send),
 			receiver: Mutex::new(Some(recv)),
-			timeout: Duration::from_secs(QUEUE_TIMEOUT_DURATION_SEC),
 		}
 	}
 }

 impl ConfirmationsQueue {
-	#[cfg(test)]
-	/// Creates new confirmations queue with specified timeout
-	pub fn with_timeout(timeout: Duration) -> Self {
-		let mut queue = Self::default();
-		queue.timeout = timeout;
-		queue
-	}

 	/// Blocks the thread and starts listening for notifications regarding all actions in the queue.
 	/// For each event, `listener` callback will be invoked.
@ -260,7 +246,11 @@ impl Drop for ConfirmationsQueue {
 }

 impl SigningQueue for ConfirmationsQueue {
-	fn add_request(&self, request: ConfirmationPayload) -> ConfirmationPromise {
+	fn add_request(&self, request: ConfirmationPayload) -> Result<ConfirmationPromise, QueueAddError> {
+		if self.len() > QUEUE_LIMIT {
+			return Err(QueueAddError::LimitReached);
+		}
+
 		// Increment id
 		let id = {
 			let mut last_id = self.id.lock();
@ -275,19 +265,17 @@ impl SigningQueue for ConfirmationsQueue {
 			let mut queue = self.queue.write();
 			queue.insert(id, ConfirmationToken {
 				result: Arc::new(Mutex::new(ConfirmationResult::Waiting)),
-				handle: thread::current(),
+				listeners: Default::default(),
 				request: ConfirmationRequest {
 					id: id,
 					payload: request,
 				},
-				timeout: self.timeout,
 			});
 			queue.get(&id).map(|token| token.as_promise()).expect("Token was just inserted.")
 		};
 		// Notify listeners
 		self.notify(QueueEvent::NewRequest(id));
-		res
-
+		Ok(res)
 	}

 	fn peek(&self, id: &U256) -> Option<ConfirmationRequest> {
@ -325,7 +313,7 @@ impl SigningQueue for ConfirmationsQueue {
 mod test {
 	use std::time::Duration;
 	use std::thread;
-	use std::sync::Arc;
+	use std::sync::{mpsc, Arc};
 	use util::{Address, U256, H256, Mutex};
 	use v1::helpers::{SigningQueue, ConfirmationsQueue, QueueEvent, FilledTransactionRequest, ConfirmationPayload};
 	use v1::types::H256 as NH256;
@ -352,8 +340,12 @@ mod test {
 		// when
 		let q = queue.clone();
 		let handle = thread::spawn(move || {
-			let v = q.add_request(request);
-			v.wait_with_timeout().expect("Should return hash")
+			let v = q.add_request(request).unwrap();
+			let (tx, rx) = mpsc::channel();
+			v.wait_for_result(move |res| {
+				tx.send(res).unwrap();
+			});
+			rx.recv().unwrap().expect("Should return hash")
 		});

 		let id = U256::from(1);
@ -361,10 +353,10 @@ mod test {
 			// Just wait for the other thread to start
 			thread::sleep(Duration::from_millis(100));
 		}
-		queue.request_confirmed(id, to_value(&NH256::from(H256::from(1))));
+		queue.request_confirmed(id, Ok(to_value(&NH256::from(H256::from(1)))));

 		// then
-		assert_eq!(handle.join().expect("Thread should finish nicely"), to_value(&NH256::from(H256::from(1))));
+		assert_eq!(handle.join().expect("Thread should finish nicely"), Ok(to_value(&NH256::from(H256::from(1)))));
 	}

 	#[test]
@ -383,7 +375,7 @@ mod test {
 				*v = Some(notification);
 			}).expect("Should be closed nicely.")
 		});
-		queue.add_request(request);
+		queue.add_request(request).unwrap();
 		queue.finish();

 		// then
@ -399,7 +391,7 @@ mod test {
 		let request = request();

 		// when
-		queue.add_request(request.clone());
+		queue.add_request(request.clone()).unwrap();
 		let all = queue.requests();

 		// then
--- a/rpc/src/v1/impls/eth.rs
+++ b/rpc/src/v1/impls/eth.rs
@ -131,7 +131,7 @@ impl<C, S: ?Sized, M, EM> EthClient<C, S, M, EM> where
 					},
 					extra_data: Bytes::new(view.extra_data())
 				};
-				to_value(&block)
+				Ok(to_value(&block))
 			},
 			_ => Ok(Value::Null)
 		}
@ -139,7 +139,7 @@ impl<C, S: ?Sized, M, EM> EthClient<C, S, M, EM> where

 	fn transaction(&self, id: TransactionID) -> Result<Value, Error> {
 		match take_weak!(self.client).transaction(id) {
-			Some(t) => to_value(&Transaction::from(t)),
+			Some(t) => Ok(to_value(&Transaction::from(t))),
 			None => Ok(Value::Null)
 		}
 	}
@ -177,7 +177,7 @@ impl<C, S: ?Sized, M, EM> EthClient<C, S, M, EM> where
 			uncles: vec![],
 			transactions: BlockTransactions::Hashes(vec![]),
 		};
-		to_value(&block)
+		Ok(to_value(&block))
 	}

 	fn sign_call(&self, request: CRequest) -> Result<SignedTransaction, Error> {
@ -270,28 +270,28 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 				}
 			}
 		};
-		to_value(&res)
+		Ok(to_value(&res))
 	}

 	fn author(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));

-		to_value(&RpcH160::from(take_weak!(self.miner).author()))
+		Ok(to_value(&RpcH160::from(take_weak!(self.miner).author())))
 	}

 	fn is_mining(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));

-		to_value(&(take_weak!(self.miner).is_sealing()))
+		Ok(to_value(&(take_weak!(self.miner).is_sealing())))
 	}

 	fn hashrate(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));

-		to_value(&RpcU256::from(self.external_miner.hashrate()))
+		Ok(to_value(&RpcU256::from(self.external_miner.hashrate())))
 	}

 	fn gas_price(&self, params: Params) -> Result<Value, Error> {
@ -299,7 +299,7 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 		try!(expect_no_params(params));

 		let (client, miner) = (take_weak!(self.client), take_weak!(self.miner));
-		to_value(&RpcU256::from(default_gas_price(&*client, &*miner)))
+		Ok(to_value(&RpcU256::from(default_gas_price(&*client, &*miner))))
 	}

 	fn accounts(&self, params: Params) -> Result<Value, Error> {
@ -308,14 +308,14 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where

 		let store = take_weak!(self.accounts);
 		let accounts = try!(store.accounts().map_err(|e| errors::internal("Could not fetch accounts.", e)));
-		to_value(&accounts.into_iter().map(Into::into).collect::<Vec<RpcH160>>())
+		Ok(to_value(&accounts.into_iter().map(Into::into).collect::<Vec<RpcH160>>()))
 	}

 	fn block_number(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));

-		to_value(&RpcU256::from(take_weak!(self.client).chain_info().best_block_number))
+		Ok(to_value(&RpcU256::from(take_weak!(self.client).chain_info().best_block_number)))
 	}

 	fn balance(&self, params: Params) -> Result<Value, Error> {
@ -324,9 +324,9 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 			.and_then(|(address, block_number,)| {
 				let address: Address = RpcH160::into(address);
 				match block_number {
-					BlockNumber::Pending => to_value(&RpcU256::from(take_weak!(self.miner).balance(&*take_weak!(self.client), &address))),
+					BlockNumber::Pending => Ok(to_value(&RpcU256::from(take_weak!(self.miner).balance(&*take_weak!(self.client), &address)))),
 					id => match take_weak!(self.client).balance(&address, id.into()) {
-						Some(balance) => to_value(&RpcU256::from(balance)),
+						Some(balance) => Ok(to_value(&RpcU256::from(balance))),
 						None => Err(errors::state_pruned()),
 					}
 				}
@ -340,9 +340,9 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 				let address: Address = RpcH160::into(address);
 				let position: U256 = RpcU256::into(position);
 				match block_number {
-					BlockNumber::Pending => to_value(&RpcU256::from(take_weak!(self.miner).storage_at(&*take_weak!(self.client), &address, &H256::from(position)))),
+					BlockNumber::Pending => Ok(to_value(&RpcU256::from(take_weak!(self.miner).storage_at(&*take_weak!(self.client), &address, &H256::from(position))))),
 					id => match take_weak!(self.client).storage_at(&address, &H256::from(position), id.into()) {
-						Some(s) => to_value(&RpcH256::from(s)),
+						Some(s) => Ok(to_value(&RpcH256::from(s))),
 						None => Err(errors::state_pruned()),
 					}
 				}
@ -356,9 +356,9 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 			.and_then(|(address, block_number,)| {
 				let address: Address = RpcH160::into(address);
 				match block_number {
-					BlockNumber::Pending => to_value(&RpcU256::from(take_weak!(self.miner).nonce(&*take_weak!(self.client), &address))),
+					BlockNumber::Pending => Ok(to_value(&RpcU256::from(take_weak!(self.miner).nonce(&*take_weak!(self.client), &address)))),
 					id => match take_weak!(self.client).nonce(&address, id.into()) {
-						Some(nonce) => to_value(&RpcU256::from(nonce)),
+						Some(nonce) => Ok(to_value(&RpcU256::from(nonce))),
 						None => Err(errors::state_pruned()),
 					}
 				}
@ -370,18 +370,18 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 		from_params::<(RpcH256,)>(params)
 			.and_then(|(hash,)| // match
 				take_weak!(self.client).block(BlockID::Hash(hash.into()))
-					.map_or(Ok(Value::Null), |bytes| to_value(&RpcU256::from(BlockView::new(&bytes).transactions_count()))))
+					.map_or(Ok(Value::Null), |bytes| Ok(to_value(&RpcU256::from(BlockView::new(&bytes).transactions_count())))))
 	}

 	fn block_transaction_count_by_number(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		from_params::<(BlockNumber,)>(params)
 			.and_then(|(block_number,)| match block_number {
-				BlockNumber::Pending => to_value(
+				BlockNumber::Pending => Ok(to_value(
 					&RpcU256::from(take_weak!(self.miner).status().transactions_in_pending_block)
-				),
+				)),
 				_ => take_weak!(self.client).block(block_number.into())
-						.map_or(Ok(Value::Null), |bytes| to_value(&RpcU256::from(BlockView::new(&bytes).transactions_count())))
+						.map_or(Ok(Value::Null), |bytes| Ok(to_value(&RpcU256::from(BlockView::new(&bytes).transactions_count()))))
 			})
 	}

@ -390,16 +390,16 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 		from_params::<(RpcH256,)>(params)
 			.and_then(|(hash,)|
 				take_weak!(self.client).block(BlockID::Hash(hash.into()))
-					.map_or(Ok(Value::Null), |bytes| to_value(&RpcU256::from(BlockView::new(&bytes).uncles_count()))))
+					.map_or(Ok(Value::Null), |bytes| Ok(to_value(&RpcU256::from(BlockView::new(&bytes).uncles_count())))))
 	}

 	fn block_uncles_count_by_number(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		from_params::<(BlockNumber,)>(params)
 			.and_then(|(block_number,)| match block_number {
-				BlockNumber::Pending => to_value(&RpcU256::from(0)),
+				BlockNumber::Pending => Ok(to_value(&RpcU256::from(0))),
 				_ => take_weak!(self.client).block(block_number.into())
-						.map_or(Ok(Value::Null), |bytes| to_value(&RpcU256::from(BlockView::new(&bytes).uncles_count())))
+						.map_or(Ok(Value::Null), |bytes| Ok(to_value(&RpcU256::from(BlockView::new(&bytes).uncles_count()))))
 			})
 	}

@ -409,9 +409,9 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 			.and_then(|(address, block_number,)| {
 				let address: Address = RpcH160::into(address);
 				match block_number {
-					BlockNumber::Pending => to_value(&take_weak!(self.miner).code(&*take_weak!(self.client), &address).map_or_else(Bytes::default, Bytes::new)),
+					BlockNumber::Pending => Ok(to_value(&take_weak!(self.miner).code(&*take_weak!(self.client), &address).map_or_else(Bytes::default, Bytes::new))),
 					_ => match take_weak!(self.client).code(&address, block_number.into()) {
-						Some(code) => to_value(&code.map_or_else(Bytes::default, Bytes::new)),
+						Some(code) => Ok(to_value(&code.map_or_else(Bytes::default, Bytes::new))),
 						None => Err(errors::state_pruned()),
 					},
 				}
@ -437,7 +437,7 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 				let miner = take_weak!(self.miner);
 				let hash: H256 = hash.into();
 				match miner.transaction(&hash) {
-					Some(pending_tx) => to_value(&Transaction::from(pending_tx)),
+					Some(pending_tx) => Ok(to_value(&Transaction::from(pending_tx))),
 					None => self.transaction(TransactionID::Hash(hash))
 				}
 			})
@ -462,11 +462,11 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 				let miner = take_weak!(self.miner);
 				let hash: H256 = hash.into();
 				match (miner.pending_receipt(&hash), self.options.allow_pending_receipt_query) {
-					(Some(receipt), true) => to_value(&Receipt::from(receipt)),
+					(Some(receipt), true) => Ok(to_value(&Receipt::from(receipt))),
 					_ => {
 						let client = take_weak!(self.client);
 						let receipt = client.transaction_receipt(TransactionID::Hash(hash));
-						to_value(&receipt.map(Receipt::from))
+						Ok(to_value(&receipt.map(Receipt::from)))
 					}
 				}
 			})
@ -492,7 +492,7 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 		if Command::new(SOLC).output().is_ok() {
 			compilers.push("solidity".to_owned())
 		}
-		to_value(&compilers)
+		Ok(to_value(&compilers))
 	}

 	fn logs(&self, params: Params) -> Result<Value, Error> {
@ -511,7 +511,7 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 					logs.extend(pending);
 				}

-				to_value(&logs)
+				Ok(to_value(&logs))
 			})
 	}

@ -550,9 +550,9 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 				Err(errors::no_new_work())
 			} else if self.options.send_block_number_in_get_work {
 				let block_number = RpcU256::from(b.block().header().number());
-				to_value(&(RpcH256::from(pow_hash), RpcH256::from(seed_hash), RpcH256::from(target), block_number))
+				Ok(to_value(&(RpcH256::from(pow_hash), RpcH256::from(seed_hash), RpcH256::from(target), block_number)))
 			} else {
-				to_value(&(RpcH256::from(pow_hash), RpcH256::from(seed_hash), RpcH256::from(target)))
+				Ok(to_value(&(RpcH256::from(pow_hash), RpcH256::from(seed_hash), RpcH256::from(target))))
 			}
 		}).unwrap_or(Err(Error::internal_error()))	// no work found.
 	}
@ -568,7 +568,7 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 			let client = take_weak!(self.client);
 			let seal = vec![encode(&mix_hash).to_vec(), encode(&nonce).to_vec()];
 			let r = miner.submit_seal(&*client, pow_hash, seal);
-			to_value(&r.is_ok())
+			Ok(to_value(&r.is_ok()))
 		})
 	}

@ -576,7 +576,7 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 		try!(self.active());
 		from_params::<(RpcU256, RpcH256)>(params).and_then(|(rate, id)| {
 			self.external_miner.submit_hashrate(rate.into(), id.into());
-			to_value(&true)
+			Ok(to_value(&true))
 		})
 	}

@ -587,7 +587,7 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 				let raw_transaction = raw_transaction.to_vec();
 				match UntrustedRlp::new(&raw_transaction).as_val() {
 					Ok(signed_transaction) => dispatch_transaction(&*take_weak!(self.client), &*take_weak!(self.miner), signed_transaction),
-					Err(_) => to_value(&RpcH256::from(H256::from(0))),
+					Err(_) => Ok(to_value(&RpcH256::from(H256::from(0)))),
 				}
 		})
 	}
@ -602,7 +602,7 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 					BlockNumber::Pending => take_weak!(self.miner).call(&*take_weak!(self.client), &signed, Default::default()),
 					block_number => take_weak!(self.client).call(&signed, block_number.into(), Default::default()),
 				};
-				to_value(&r.map(|e| Bytes(e.output)).unwrap_or(Bytes::new(vec![])))
+				Ok(to_value(&r.map(|e| Bytes(e.output)).unwrap_or(Bytes::new(vec![]))))
 			})
 	}

@ -616,7 +616,7 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 					BlockNumber::Pending => take_weak!(self.miner).call(&*take_weak!(self.client), &signed, Default::default()),
 					block => take_weak!(self.client).call(&signed, block.into(), Default::default()),
 				};
-				to_value(&RpcU256::from(r.map(|res| res.gas_used + res.refunded).unwrap_or(From::from(0))))
+				Ok(to_value(&RpcU256::from(r.map(|res| res.gas_used + res.refunded).unwrap_or(From::from(0)))))
 			})
 	}

@ -653,7 +653,7 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where

 						let s = String::from_utf8_lossy(&output.stdout);
 						if let Some(hex) = s.lines().skip_while(|ref l| !l.contains("Binary")).skip(1).next() {
-							to_value(&Bytes::new(hex.from_hex().unwrap_or(vec![])))
+							Ok(to_value(&Bytes::new(hex.from_hex().unwrap_or(vec![]))))
 						} else {
 							Err(errors::compilation("Unexpected output."))
 						}
--- a/rpc/src/v1/impls/eth_filter.rs
+++ b/rpc/src/v1/impls/eth_filter.rs
@ -70,7 +70,7 @@ impl<C, M> EthFilter for EthFilterClient<C, M> where
 				let mut polls = self.polls.lock();
 				let block_number = take_weak!(self.client).chain_info().best_block_number;
 				let id = polls.create_poll(PollFilter::Logs(block_number, Default::default(), filter));
-				to_value(&RpcU256::from(id))
+				Ok(to_value(&RpcU256::from(id)))
 			})
 	}

@ -80,7 +80,7 @@ impl<C, M> EthFilter for EthFilterClient<C, M> where

 		let mut polls = self.polls.lock();
 		let id = polls.create_poll(PollFilter::Block(take_weak!(self.client).chain_info().best_block_number));
-		to_value(&RpcU256::from(id))
+		Ok(to_value(&RpcU256::from(id)))
 	}

 	fn new_pending_transaction_filter(&self, params: Params) -> Result<Value, Error> {
@ -91,7 +91,7 @@ impl<C, M> EthFilter for EthFilterClient<C, M> where
 		let pending_transactions = take_weak!(self.miner).pending_transactions_hashes();
 		let id = polls.create_poll(PollFilter::PendingTransaction(pending_transactions));

-		to_value(&RpcU256::from(id))
+		Ok(to_value(&RpcU256::from(id)))
 	}

 	fn filter_changes(&self, params: Params) -> Result<Value, Error> {
@ -114,7 +114,7 @@ impl<C, M> EthFilter for EthFilterClient<C, M> where

 							*block_number = current_number;

-							to_value(&hashes)
+							Ok(to_value(&hashes))
 						},
 						PollFilter::PendingTransaction(ref mut previous_hashes) => {
 							// get hashes of pending transactions
@ -137,7 +137,7 @@ impl<C, M> EthFilter for EthFilterClient<C, M> where
 							*previous_hashes = current_hashes;

 							// return new hashes
-							to_value(&new_hashes)
+							Ok(to_value(&new_hashes))
 						},
 						PollFilter::Logs(ref mut block_number, ref mut previous_logs, ref filter) => {
 							// retrive the current block number
@ -178,7 +178,7 @@ impl<C, M> EthFilter for EthFilterClient<C, M> where
 							// we want to get logs
 							*block_number = current_number + 1;

-							to_value(&logs)
+							Ok(to_value(&logs))
 						}
 					}
 				}
@ -203,7 +203,7 @@ impl<C, M> EthFilter for EthFilterClient<C, M> where
 							logs.extend(pending_logs(&*take_weak!(self.miner), &filter));
 						}

-						to_value(&logs)
+						Ok(to_value(&logs))
 					},
 					// just empty array
 					_ => Ok(Value::Array(vec![] as Vec<Value>)),
@ -214,7 +214,7 @@ impl<C, M> EthFilter for EthFilterClient<C, M> where
 	fn uninstall_filter(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		from_params::<(Index,)>(params)
-			.and_then(|(index,)| {
+			.map(|(index,)| {
 				self.polls.lock().remove_poll(&index.value());
 				to_value(&true)
 			})
--- a/rpc/src/v1/impls/eth_signing.rs
+++ b/rpc/src/v1/impls/eth_signing.rs
@ -53,6 +53,11 @@ pub struct EthSigningQueueClient<C, M> where C: MiningBlockChainClient, M: Miner

 const MAX_PENDING_DURATION: u64 = 60 * 60;

+pub enum DispatchResult {
+	Promise(ConfirmationPromise),
+	Value(Value),
+}
+
 impl<C, M> EthSigningQueueClient<C, M> where C: MiningBlockChainClient, M: MinerService {
 	/// Creates a new signing queue client given shared signing queue.
 	pub fn new(queue: &Arc<ConfirmationsQueue>, client: &Arc<C>, miner: &Arc<M>, accounts: &Arc<AccountProvider>) -> Self {
@ -71,23 +76,24 @@ impl<C, M> EthSigningQueueClient<C, M> where C: MiningBlockChainClient, M: Miner
 		Ok(())
 	}

-	fn dispatch_sign<F: FnOnce(ConfirmationPromise) -> Result<Value, Error>>(&self, params: Params, f: F) -> Result<Value, Error> {
+	fn dispatch_sign(&self, params: Params) -> Result<DispatchResult, Error> {
 		from_params::<(RpcH160, RpcH256)>(params).and_then(|(address, msg)| {
 			let address: Address = address.into();
 			let msg: H256 = msg.into();

 			let accounts = take_weak!(self.accounts);
 			if accounts.is_unlocked(address) {
-				return to_value(&accounts.sign(address, msg).ok().map_or_else(RpcH520::default, Into::into));
+				return Ok(DispatchResult::Value(to_value(&accounts.sign(address, msg).ok().map_or_else(RpcH520::default, Into::into))))
 			}

 			let queue = take_weak!(self.queue);
-			let promise = queue.add_request(ConfirmationPayload::Sign(address, msg));
-			f(promise)
+			queue.add_request(ConfirmationPayload::Sign(address, msg))
+				.map(DispatchResult::Promise)
+				.map_err(|_| errors::request_rejected_limit())
 		})
 	}

-	fn dispatch_transaction<F: FnOnce(ConfirmationPromise) -> Result<Value, Error>>(&self, params: Params, f: F) -> Result<Value, Error> {
+	fn dispatch_transaction(&self, params: Params) -> Result<DispatchResult, Error> {
 		from_params::<(TransactionRequest, )>(params)
 			.and_then(|(request, )| {
 				let request: TRequest = request.into();
@ -96,13 +102,14 @@ impl<C, M> EthSigningQueueClient<C, M> where C: MiningBlockChainClient, M: Miner

 				if accounts.is_unlocked(request.from) {
 					let sender = request.from;
-					return sign_and_dispatch(&*client, &*miner, request, &*accounts, sender);
+					return sign_and_dispatch(&*client, &*miner, request, &*accounts, sender).map(DispatchResult::Value);
 				}

 				let queue = take_weak!(self.queue);
 				let request = fill_optional_fields(request, &*client, &*miner);
-				let promise = queue.add_request(ConfirmationPayload::Transaction(request));
-				f(promise)
+				queue.add_request(ConfirmationPayload::Transaction(request))
+					.map(DispatchResult::Promise)
+					.map_err(|_| errors::request_rejected_limit())
 			})
 	}
 }
@ -111,35 +118,53 @@ impl<C, M> EthSigning for EthSigningQueueClient<C, M>
 	where C: MiningBlockChainClient + 'static, M: MinerService + 'static
 {

-	fn sign(&self, params: Params) -> Result<Value, Error> {
-		try!(self.active());
-		self.dispatch_sign(params, |promise| {
-			promise.wait_with_timeout().unwrap_or_else(|| to_value(&RpcH520::default()))
-		})
+	fn sign(&self, params: Params, ready: Ready) {
+		let res = self.active().and_then(|_| self.dispatch_sign(params));
+		match res {
+			Ok(DispatchResult::Promise(promise)) => {
+				promise.wait_for_result(move |result| {
+					ready.ready(result.unwrap_or_else(|| Err(errors::request_rejected())))
+				})
+			},
+			Ok(DispatchResult::Value(v)) => ready.ready(Ok(v)),
+			Err(e) => ready.ready(Err(e)),
+		}
 	}

 	fn post_sign(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
-		self.dispatch_sign(params, |promise| {
-			let id = promise.id();
-			self.pending.lock().insert(id, promise);
-			to_value(&RpcU256::from(id))
+		self.dispatch_sign(params).map(|result| match result {
+			DispatchResult::Value(v) => v,
+			DispatchResult::Promise(promise) => {
+				let id = promise.id();
+				self.pending.lock().insert(id, promise);
+				to_value(&RpcU256::from(id))
+			},
 		})
 	}

-	fn send_transaction(&self, params: Params) -> Result<Value, Error> {
-		try!(self.active());
-		self.dispatch_transaction(params, |promise| {
-			promise.wait_with_timeout().unwrap_or_else(|| to_value(&RpcH256::default()))
-		})
+	fn send_transaction(&self, params: Params, ready: Ready) {
+		let res = self.active().and_then(|_| self.dispatch_transaction(params));
+		match res {
+			Ok(DispatchResult::Promise(promise)) => {
+				promise.wait_for_result(move |result| {
+					ready.ready(result.unwrap_or_else(|| Err(errors::request_rejected())))
+				})
+			},
+			Ok(DispatchResult::Value(v)) => ready.ready(Ok(v)),
+			Err(e) => ready.ready(Err(e)),
+		}
 	}

 	fn post_transaction(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
-		self.dispatch_transaction(params, |promise| {
-			let id = promise.id();
-			self.pending.lock().insert(id, promise);
-			to_value(&RpcU256::from(id))
+		self.dispatch_transaction(params).map(|result| match result {
+			DispatchResult::Value(v) => v,
+			DispatchResult::Promise(promise) => {
+				let id = promise.id();
+				self.pending.lock().insert(id, promise);
+				to_value(&RpcU256::from(id))
+			},
 		})
 	}

@ -196,23 +221,24 @@ impl<C, M> EthSigning for EthSigningUnsafeClient<C, M> where
 	C: MiningBlockChainClient + 'static,
 	M: MinerService + 'static {

-	fn sign(&self, params: Params) -> Result<Value, Error> {
-		try!(self.active());
-		from_params::<(RpcH160, RpcH256)>(params).and_then(|(address, msg)| {
-			let address: Address = address.into();
-			let msg: H256 = msg.into();
-			to_value(&take_weak!(self.accounts).sign(address, msg).ok().map_or_else(RpcH520::default, Into::into))
-		})
+	fn sign(&self, params: Params, ready: Ready) {
+		ready.ready(self.active()
+			.and_then(|_| from_params::<(RpcH160, RpcH256)>(params))
+			.and_then(|(address, msg)| {
+				let address: Address = address.into();
+				let msg: H256 = msg.into();
+				Ok(to_value(&take_weak!(self.accounts).sign(address, msg).ok().map_or_else(RpcH520::default, Into::into)))
+			}))
 	}

-	fn send_transaction(&self, params: Params) -> Result<Value, Error> {
-		try!(self.active());
-		from_params::<(TransactionRequest, )>(params)
+	fn send_transaction(&self, params: Params, ready: Ready) {
+		ready.ready(self.active()
+			.and_then(|_| from_params::<(TransactionRequest, )>(params))
 			.and_then(|(request, )| {
 				let request: TRequest = request.into();
 				let sender = request.from;
 				sign_and_dispatch(&*take_weak!(self.client), &*take_weak!(self.miner), request, &*take_weak!(self.accounts), sender)
-			})
+			}))
 	}

 	fn post_sign(&self, _: Params) -> Result<Value, Error> {
--- a/rpc/src/v1/impls/ethcore.rs
+++ b/rpc/src/v1/impls/ethcore.rs
@ -82,50 +82,50 @@ impl<C, M, S: ?Sized> Ethcore for EthcoreClient<C, M, S> where M: MinerService +
 	fn transactions_limit(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
-		to_value(&take_weak!(self.miner).transactions_limit())
+		Ok(to_value(&take_weak!(self.miner).transactions_limit()))
 	}

 	fn min_gas_price(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
-		to_value(&U256::from(take_weak!(self.miner).minimal_gas_price()))
+		Ok(to_value(&U256::from(take_weak!(self.miner).minimal_gas_price())))
 	}

 	fn extra_data(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
-		to_value(&Bytes::new(take_weak!(self.miner).extra_data()))
+		Ok(to_value(&Bytes::new(take_weak!(self.miner).extra_data())))
 	}

 	fn gas_floor_target(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
-		to_value(&U256::from(take_weak!(self.miner).gas_floor_target()))
+		Ok(to_value(&U256::from(take_weak!(self.miner).gas_floor_target())))
 	}

 	fn gas_ceil_target(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
-		to_value(&U256::from(take_weak!(self.miner).gas_ceil_target()))
+		Ok(to_value(&U256::from(take_weak!(self.miner).gas_ceil_target())))
 	}

 	fn dev_logs(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
 		let logs = self.logger.logs();
-		to_value(&logs.as_slice())
+		Ok(to_value(&logs.as_slice()))
 	}

 	fn dev_logs_levels(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
-		to_value(&self.logger.levels())
+		Ok(to_value(&self.logger.levels()))
 	}

 	fn net_chain(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
-		to_value(&self.settings.chain)
+		Ok(to_value(&self.settings.chain))
 	}

 	fn net_peers(&self, params: Params) -> Result<Value, Error> {
@ -135,23 +135,23 @@ impl<C, M, S: ?Sized> Ethcore for EthcoreClient<C, M, S> where M: MinerService +
 		let sync_status = take_weak!(self.sync).status();
 		let net_config = take_weak!(self.net).network_config();

-		to_value(&Peers {
+		Ok(to_value(&Peers {
 			active: sync_status.num_active_peers,
 			connected: sync_status.num_peers,
 			max: sync_status.current_max_peers(net_config.min_peers, net_config.max_peers),
-		})
+		}))
 	}

 	fn net_port(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
-		to_value(&self.settings.network_port)
+		Ok(to_value(&self.settings.network_port))
 	}

 	fn node_name(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
-		to_value(&self.settings.name)
+		Ok(to_value(&self.settings.name))
 	}

 	fn registry_address(&self, params: Params) -> Result<Value, Error> {
@ -162,7 +162,7 @@ impl<C, M, S: ?Sized> Ethcore for EthcoreClient<C, M, S> where M: MinerService +
 			.get("registrar")
 			.and_then(|s| Address::from_str(s).ok())
 			.map(|s| H160::from(s));
-		to_value(&r)
+		Ok(to_value(&r))
 	}

 	fn rpc_settings(&self, params: Params) -> Result<Value, Error> {
@ -178,7 +178,7 @@ impl<C, M, S: ?Sized> Ethcore for EthcoreClient<C, M, S> where M: MinerService +
 	fn default_extra_data(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
-		to_value(&Bytes::new(version_data()))
+		Ok(to_value(&Bytes::new(version_data())))
 	}

 	fn gas_price_statistics(&self, params: Params) -> Result<Value, Error> {
@ -186,10 +186,10 @@ impl<C, M, S: ?Sized> Ethcore for EthcoreClient<C, M, S> where M: MinerService +
 		try!(expect_no_params(params));

 		match take_weak!(self.client).gas_price_statistics(100, 8) {
-			Ok(stats) => to_value(&stats
+			Ok(stats) => Ok(to_value(&stats
 				.into_iter()
-				.map(|x| to_value(&U256::from(x)).expect("x must be U256; qed"))
-				.collect::<Vec<_>>()),
+				.map(|x| to_value(&U256::from(x)))
+				.collect::<Vec<_>>())),
 			_ => Err(Error::internal_error()),
 		}
 	}
@ -200,7 +200,7 @@ impl<C, M, S: ?Sized> Ethcore for EthcoreClient<C, M, S> where M: MinerService +

 		match self.confirmations_queue {
 			None => Err(errors::signer_disabled()),
-			Some(ref queue) => to_value(&queue.len()),
+			Some(ref queue) => Ok(to_value(&queue.len())),
 		}
 	}

@ -208,12 +208,12 @@ impl<C, M, S: ?Sized> Ethcore for EthcoreClient<C, M, S> where M: MinerService +
 		try!(self.active());
 		try!(expect_no_params(params));

-		to_value(&random_phrase(12))
+		Ok(to_value(&random_phrase(12)))
 	}

 	fn phrase_to_address(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
-		from_params::<(String,)>(params).and_then(|(phrase,)|
+		from_params::<(String,)>(params).map(|(phrase,)|
 			to_value(&H160::from(Brain::new(phrase).generate().unwrap().address()))
 		)
 	}
--- a/rpc/src/v1/impls/ethcore_set.rs
+++ b/rpc/src/v1/impls/ethcore_set.rs
@ -62,7 +62,7 @@ impl<C, M> EthcoreSet for EthcoreSetClient<C, M> where
 		try!(self.active());
 		from_params::<(U256,)>(params).and_then(|(gas_price,)| {
 			take_weak!(self.miner).set_minimal_gas_price(gas_price.into());
-			to_value(&true)
+			Ok(to_value(&true))
 		})
 	}

@ -70,7 +70,7 @@ impl<C, M> EthcoreSet for EthcoreSetClient<C, M> where
 		try!(self.active());
 		from_params::<(U256,)>(params).and_then(|(target,)| {
 			take_weak!(self.miner).set_gas_floor_target(target.into());
-			to_value(&true)
+			Ok(to_value(&true))
 		})
 	}

@ -78,7 +78,7 @@ impl<C, M> EthcoreSet for EthcoreSetClient<C, M> where
 		try!(self.active());
 		from_params::<(U256,)>(params).and_then(|(target,)| {
 			take_weak!(self.miner).set_gas_ceil_target(target.into());
-			to_value(&true)
+			Ok(to_value(&true))
 		})
 	}

@ -86,7 +86,7 @@ impl<C, M> EthcoreSet for EthcoreSetClient<C, M> where
 		try!(self.active());
 		from_params::<(Bytes,)>(params).and_then(|(extra_data,)| {
 			take_weak!(self.miner).set_extra_data(extra_data.to_vec());
-			to_value(&true)
+			Ok(to_value(&true))
 		})
 	}

@ -94,7 +94,7 @@ impl<C, M> EthcoreSet for EthcoreSetClient<C, M> where
 		try!(self.active());
 		from_params::<(H160,)>(params).and_then(|(author,)| {
 			take_weak!(self.miner).set_author(author.into());
-			to_value(&true)
+			Ok(to_value(&true))
 		})
 	}

@ -102,7 +102,7 @@ impl<C, M> EthcoreSet for EthcoreSetClient<C, M> where
 		try!(self.active());
 		from_params::<(usize,)>(params).and_then(|(limit,)| {
 			take_weak!(self.miner).set_transactions_limit(limit);
-			to_value(&true)
+			Ok(to_value(&true))
 		})
 	}

@ -110,7 +110,7 @@ impl<C, M> EthcoreSet for EthcoreSetClient<C, M> where
 		try!(self.active());
 		from_params::<(U256,)>(params).and_then(|(limit,)| {
 			take_weak!(self.miner).set_tx_gas_limit(limit.into());
-			to_value(&true)
+			Ok(to_value(&true))
 		})
 	}

@ -118,7 +118,7 @@ impl<C, M> EthcoreSet for EthcoreSetClient<C, M> where
 		try!(self.active());
 		from_params::<(String,)>(params).and_then(|(peer,)| {
 			match take_weak!(self.net).add_reserved_peer(peer) {
-				Ok(()) => to_value(&true),
+				Ok(()) => Ok(to_value(&true)),
 				Err(e) => Err(errors::invalid_params("Peer address", e)),
 			}
 		})
@ -128,7 +128,7 @@ impl<C, M> EthcoreSet for EthcoreSetClient<C, M> where
 		try!(self.active());
 		from_params::<(String,)>(params).and_then(|(peer,)| {
 			match take_weak!(self.net).remove_reserved_peer(peer) {
-				Ok(()) => to_value(&true),
+				Ok(()) => Ok(to_value(&true)),
 				Err(e) => Err(errors::invalid_params("Peer address", e)),
 			}
 		})
@ -138,14 +138,14 @@ impl<C, M> EthcoreSet for EthcoreSetClient<C, M> where
 		try!(self.active());
 		try!(expect_no_params(params));
 		take_weak!(self.net).deny_unreserved_peers();
-		to_value(&true)
+		Ok(to_value(&true))
 	}

 	fn accept_non_reserved_peers(&self, params: Params) -> Result<Value, Error> {
 		try!(self.active());
 		try!(expect_no_params(params));
 		take_weak!(self.net).accept_unreserved_peers();
-		to_value(&true)
+		Ok(to_value(&true))
 	}

 	fn start_network(&self, params: Params) -> Result<Value, Error> {
--- a/rpc/src/v1/impls/personal.rs
+++ b/rpc/src/v1/impls/personal.rs
@ -63,9 +63,9 @@ impl<C: 'static, M: 'static> Personal for PersonalClient<C, M> where C: MiningBl
 		try!(self.active());
 		try!(expect_no_params(params));

-		self.signer_port
+		Ok(self.signer_port
 			.map(|v| to_value(&v))
-			.unwrap_or_else(|| to_value(&false))
+			.unwrap_or_else(|| to_value(&false)))
 	}

 	fn accounts(&self, params: Params) -> Result<Value, Error> {
@ -74,7 +74,7 @@ impl<C: 'static, M: 'static> Personal for PersonalClient<C, M> where C: MiningBl

 		let store = take_weak!(self.accounts);
 		let accounts = try!(store.accounts().map_err(|e| errors::internal("Could not fetch accounts.", e)));
-		to_value(&accounts.into_iter().map(Into::into).collect::<Vec<RpcH160>>())
+		Ok(to_value(&accounts.into_iter().map(Into::into).collect::<Vec<RpcH160>>()))
 	}

 	fn new_account(&self, params: Params) -> Result<Value, Error> {
@ -83,7 +83,7 @@ impl<C: 'static, M: 'static> Personal for PersonalClient<C, M> where C: MiningBl
 			|(pass, )| {
 				let store = take_weak!(self.accounts);
 				match store.new_account(&pass) {
-					Ok(address) => to_value(&RpcH160::from(address)),
+					Ok(address) => Ok(to_value(&RpcH160::from(address))),
 					Err(e) => Err(errors::account("Could not create account.", e)),
 				}
 			}
@ -96,7 +96,7 @@ impl<C: 'static, M: 'static> Personal for PersonalClient<C, M> where C: MiningBl
 			|(phrase, pass, )| {
 				let store = take_weak!(self.accounts);
 				match store.insert_account(*Brain::new(phrase).generate().unwrap().secret(), &pass) {
-					Ok(address) => to_value(&RpcH160::from(address)),
+					Ok(address) => Ok(to_value(&RpcH160::from(address))),
 					Err(e) => Err(errors::account("Could not create account.", e)),
 				}
 			}
@ -109,7 +109,7 @@ impl<C: 'static, M: 'static> Personal for PersonalClient<C, M> where C: MiningBl
 			|(json, pass, )| {
 				let store = take_weak!(self.accounts);
 				match store.import_presale(json.as_bytes(), &pass).or_else(|_| store.import_wallet(json.as_bytes(), &pass)) {
-					Ok(address) => to_value(&RpcH160::from(address)),
+					Ok(address) => Ok(to_value(&RpcH160::from(address))),
 					Err(e) => Err(errors::account("Could not create account.", e)),
 				}
 			}
@ -174,10 +174,10 @@ impl<C: 'static, M: 'static> Personal for PersonalClient<C, M> where C: MiningBl
 		let other = store.addresses_info().expect("addresses_info always returns Ok; qed");
 		Ok(Value::Object(info.into_iter().chain(other.into_iter()).map(|(a, v)| {
 			let m = map![
-				"name".to_owned() => to_value(&v.name).unwrap(),
-				"meta".to_owned() => to_value(&v.meta).unwrap(),
+				"name".to_owned() => to_value(&v.name),
+				"meta".to_owned() => to_value(&v.meta),
 				"uuid".to_owned() => if let &Some(ref uuid) = &v.uuid {
-					to_value(uuid).unwrap()
+					to_value(uuid)
 				} else {
 					Value::Null
 				}
@ -190,16 +190,16 @@ impl<C: 'static, M: 'static> Personal for PersonalClient<C, M> where C: MiningBl
 		try!(self.active());
 		try!(expect_no_params(params));
 		let store = take_weak!(self.accounts);
-		to_value(&store.list_geth_accounts(false).into_iter().map(Into::into).collect::<Vec<RpcH160>>())
+		Ok(to_value(&store.list_geth_accounts(false).into_iter().map(Into::into).collect::<Vec<RpcH160>>()))
 	}

 	fn import_geth_accounts(&self, params: Params) -> Result<Value, Error> {
 		from_params::<(Vec<RpcH160>,)>(params).and_then(|(addresses,)| {
 			let store = take_weak!(self.accounts);
-			to_value(&try!(store
+			Ok(to_value(&try!(store
 				.import_geth_accounts(addresses.into_iter().map(Into::into).collect(), false)
 				.map_err(|e| errors::account("Couldn't import Geth accounts", e))
-			).into_iter().map(Into::into).collect::<Vec<RpcH160>>())
+			).into_iter().map(Into::into).collect::<Vec<RpcH160>>()))
 		})
 	}
 }
--- a/rpc/src/v1/impls/personal_signer.rs
+++ b/rpc/src/v1/impls/personal_signer.rs
@ -60,7 +60,7 @@ impl<C: 'static, M: 'static> PersonalSigner for SignerClient<C, M> where C: Mini
 		try!(self.active());
 		try!(expect_no_params(params));
 		let queue = take_weak!(self.queue);
-		to_value(&queue.requests().into_iter().map(From::from).collect::<Vec<ConfirmationRequest>>())
+		Ok(to_value(&queue.requests().into_iter().map(From::from).collect::<Vec<ConfirmationRequest>>()))
 	}

 	fn confirm_request(&self, params: Params) -> Result<Value, Error> {
@ -104,7 +104,7 @@ impl<C: 'static, M: 'static> PersonalSigner for SignerClient<C, M> where C: Mini
 			|(id, )| {
 				let queue = take_weak!(self.queue);
 				let res = queue.request_rejected(id.into());
-				to_value(&res.is_some())
+				Ok(to_value(&res.is_some()))
 			}
 		)
 	}
--- a/rpc/src/v1/impls/traces.rs
+++ b/rpc/src/v1/impls/traces.rs
@ -80,7 +80,7 @@ impl<C, M> Traces for TracesClient<C, M> where C: BlockChainClient + 'static, M:
 				let client = take_weak!(self.client);
 				let traces = client.filter_traces(filter.into());
 				let traces = traces.map_or_else(Vec::new, |traces| traces.into_iter().map(LocalizedTrace::from).collect());
-				to_value(&traces)
+				Ok(to_value(&traces))
 			})
 	}

@ -91,7 +91,7 @@ impl<C, M> Traces for TracesClient<C, M> where C: BlockChainClient + 'static, M:
 				let client = take_weak!(self.client);
 				let traces = client.block_traces(block_number.into());
 				let traces = traces.map_or_else(Vec::new, |traces| traces.into_iter().map(LocalizedTrace::from).collect());
-				to_value(&traces)
+				Ok(to_value(&traces))
 			})
 	}

@ -102,7 +102,7 @@ impl<C, M> Traces for TracesClient<C, M> where C: BlockChainClient + 'static, M:
 				let client = take_weak!(self.client);
 				let traces = client.transaction_traces(TransactionID::Hash(transaction_hash.into()));
 				let traces = traces.map_or_else(Vec::new, |traces| traces.into_iter().map(LocalizedTrace::from).collect());
-				to_value(&traces)
+				Ok(to_value(&traces))
 			})
 	}

@ -117,7 +117,7 @@ impl<C, M> Traces for TracesClient<C, M> where C: BlockChainClient + 'static, M:
 				};
 				let trace = client.trace(id);
 				let trace = trace.map(LocalizedTrace::from);
-				to_value(&trace)
+				Ok(to_value(&trace))
 			})
 	}

@ -128,7 +128,7 @@ impl<C, M> Traces for TracesClient<C, M> where C: BlockChainClient + 'static, M:
 				let request = CallRequest::into(request);
 				let signed = try!(self.sign_call(request));
 				match take_weak!(self.client).call(&signed, block.into(), to_call_analytics(flags)) {
-					Ok(e) => to_value(&TraceResults::from(e)),
+					Ok(e) => Ok(to_value(&TraceResults::from(e))),
 					_ => Ok(Value::Null),
 				}
 			})
@ -141,7 +141,7 @@ impl<C, M> Traces for TracesClient<C, M> where C: BlockChainClient + 'static, M:
 				let raw_transaction = Bytes::to_vec(raw_transaction);
 				match UntrustedRlp::new(&raw_transaction).as_val() {
 					Ok(signed) => match take_weak!(self.client).call(&signed, block.into(), to_call_analytics(flags)) {
-						Ok(e) => to_value(&TraceResults::from(e)),
+						Ok(e) => Ok(to_value(&TraceResults::from(e))),
 						_ => Ok(Value::Null),
 					},
 					Err(e) => Err(errors::invalid_params("Transaction is not valid RLP", e)),
@ -154,7 +154,7 @@ impl<C, M> Traces for TracesClient<C, M> where C: BlockChainClient + 'static, M:
 		from_params::<(H256, _)>(params)
 			.and_then(|(transaction_hash, flags)| {
 				match take_weak!(self.client).replay(TransactionID::Hash(transaction_hash.into()), to_call_analytics(flags)) {
-					Ok(e) => to_value(&TraceResults::from(e)),
+					Ok(e) => Ok(to_value(&TraceResults::from(e))),
 					_ => Ok(Value::Null),
 				}
 			})
--- a/rpc/src/v1/impls/web3.rs
+++ b/rpc/src/v1/impls/web3.rs
@ -37,7 +37,7 @@ impl Web3 for Web3Client {
 	}

 	fn sha3(&self, params: Params) -> Result<Value, Error> {
-		from_params::<(Bytes,)>(params).and_then(
+		from_params::<(Bytes,)>(params).map(
 			|(data,)| {
 				let Bytes(ref vec) = data;
 				let sha3 = vec.sha3();
--- a/rpc/src/v1/tests/eth.rs
+++ b/rpc/src/v1/tests/eth.rs
@ -157,7 +157,7 @@ fn eth_get_balance() {
 		"id": 1
 	}"#;
 	let res_latest = r#"{"jsonrpc":"2.0","result":"0x09","id":1}"#.to_owned();
-	assert_eq!(tester.handler.handle_request(req_latest).unwrap(), res_latest);
+	assert_eq!(tester.handler.handle_request_sync(req_latest).unwrap(), res_latest);

 	// non-existant account
 	let req_new_acc = r#"{
@ -168,7 +168,7 @@ fn eth_get_balance() {
 	}"#;

 	let res_new_acc = r#"{"jsonrpc":"2.0","result":"0x00","id":3}"#.to_owned();
-	assert_eq!(tester.handler.handle_request(req_new_acc).unwrap(), res_new_acc);
+	assert_eq!(tester.handler.handle_request_sync(req_new_acc).unwrap(), res_new_acc);
 }

 #[test]
@ -183,7 +183,7 @@ fn eth_block_number() {
 	}"#;

 	let res_number = r#"{"jsonrpc":"2.0","result":"0x20","id":1}"#.to_owned();
-	assert_eq!(tester.handler.handle_request(req_number).unwrap(), res_number);
+	assert_eq!(tester.handler.handle_request_sync(req_number).unwrap(), res_number);
 }

 // a frontier-like test with an expanded gas limit and balance on known account.
@ -299,7 +299,7 @@ fn eth_transaction_count() {

 	let res_before = r#"{"jsonrpc":"2.0","result":"0x00","id":15}"#;

-	assert_eq!(tester.handler.handle_request(&req_before).unwrap(), res_before);
+	assert_eq!(tester.handler.handle_request_sync(&req_before).unwrap(), res_before);

 	let req_send_trans = r#"{
 		"jsonrpc": "2.0",
@ -315,7 +315,7 @@ fn eth_transaction_count() {
 	}"#;

 	// dispatch the transaction.
-	tester.handler.handle_request(&req_send_trans).unwrap();
+	tester.handler.handle_request_sync(&req_send_trans).unwrap();

 	// we have submitted the transaction -- but this shouldn't be reflected in a "latest" query.
 	let req_after_latest = r#"{
@ -327,7 +327,7 @@ fn eth_transaction_count() {

 	let res_after_latest = r#"{"jsonrpc":"2.0","result":"0x00","id":17}"#;

-	assert_eq!(&tester.handler.handle_request(&req_after_latest).unwrap(), res_after_latest);
+	assert_eq!(&tester.handler.handle_request_sync(&req_after_latest).unwrap(), res_after_latest);

 	// the pending transactions should have been updated.
 	let req_after_pending = r#"{
@ -339,7 +339,7 @@ fn eth_transaction_count() {

 	let res_after_pending = r#"{"jsonrpc":"2.0","result":"0x01","id":18}"#;

-	assert_eq!(&tester.handler.handle_request(&req_after_pending).unwrap(), res_after_pending);
+	assert_eq!(&tester.handler.handle_request_sync(&req_after_pending).unwrap(), res_after_pending);
 }

 fn verify_transaction_counts(name: String, chain: BlockChain) {
@ -400,12 +400,12 @@ fn verify_transaction_counts(name: String, chain: BlockChain) {
 		let number = b.header_view().number();

 		let (req, res) = by_hash(hash, count, &mut id);
-		assert_eq!(tester.handler.handle_request(&req), Some(res));
+		assert_eq!(tester.handler.handle_request_sync(&req), Some(res));

 		// uncles can share block numbers, so skip them.
 		if tester.client.block_hash(BlockID::Number(number)) == Some(hash) {
 			let (req, res) = by_number(number, count, &mut id);
-			assert_eq!(tester.handler.handle_request(&req), Some(res));
+			assert_eq!(tester.handler.handle_request_sync(&req), Some(res));
 		}
 	}
 }
@ -415,7 +415,7 @@ fn starting_nonce_test() {
 	let tester = EthTester::from_spec(Spec::load(POSITIVE_NONCE_SPEC));
 	let address = Address::from(10);

-	let sample = tester.handler.handle_request(&(r#"
+	let sample = tester.handler.handle_request_sync(&(r#"
 		{
 			"jsonrpc": "2.0",
 			"method": "eth_getTransactionCount",
--- a/rpc/src/v1/tests/mocked/eth.rs
+++ b/rpc/src/v1/tests/mocked/eth.rs
@ -97,7 +97,7 @@ fn rpc_eth_protocol_version() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_protocolVersion", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"63","id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -107,7 +107,7 @@ fn rpc_eth_syncing() {
 	let tester = EthTester::default();

 	let false_res = r#"{"jsonrpc":"2.0","result":false,"id":1}"#;
-	assert_eq!(tester.io.handle_request(request), Some(false_res.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(false_res.to_owned()));

 	{
 		let mut status = tester.sync.status.write();
@ -123,7 +123,7 @@ fn rpc_eth_syncing() {
 	}

 	let true_res = r#"{"jsonrpc":"2.0","result":{"currentBlock":"0x03e8","highestBlock":"0x09c4","startingBlock":"0x00"},"id":1}"#;
-	assert_eq!(tester.io.handle_request(request), Some(true_res.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(true_res.to_owned()));

 	{
 		// finish "syncing"
@ -133,7 +133,7 @@ fn rpc_eth_syncing() {
 		}
 	}

-	assert_eq!(tester.io.handle_request(request), Some(false_res.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(false_res.to_owned()));
 }

 #[test]
@ -146,7 +146,7 @@ fn rpc_eth_hashrate() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_hashrate", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0xfffc","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -163,7 +163,7 @@ fn rpc_eth_submit_hashrate() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 	assert_eq!(tester.hashrates.lock().get(&H256::from("0x59daa26581d0acd1fce254fb7e85952f4c09d0915afd33d3886cd914bc7d283c")).cloned().unwrap().1,
 		U256::from(0x500_000));
 }
@ -188,7 +188,7 @@ fn rpc_eth_sign() {
 	}"#;
 	let res = r#"{"jsonrpc":"2.0","result":""#.to_owned() + &format!("0x{}", signed) + r#"","id":1}"#;

-	assert_eq!(tester.io.handle_request(&req), Some(res));
+	assert_eq!(tester.io.handle_request_sync(&req), Some(res));
 }

 #[test]
@ -203,13 +203,13 @@ fn rpc_eth_author() {
 		"id": 1
 	}"#;

-	assert_eq!(tester.io.handle_request(req), Some(make_res(Address::zero())));
+	assert_eq!(tester.io.handle_request_sync(req), Some(make_res(Address::zero())));

 	for i in 0..20 {
 		let addr = tester.accounts_provider.new_account(&format!("{}", i)).unwrap();
 		tester.miner.set_author(addr.clone());

-		assert_eq!(tester.io.handle_request(req), Some(make_res(addr)));
+		assert_eq!(tester.io.handle_request_sync(req), Some(make_res(addr)));
 	}
 }

@ -220,7 +220,7 @@ fn rpc_eth_mining() {

 	let request = r#"{"jsonrpc": "2.0", "method": "eth_mining", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":false,"id":1}"#;
-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -228,7 +228,7 @@ fn rpc_eth_gas_price() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_gasPrice", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x04a817c800","id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -239,7 +239,7 @@ fn rpc_eth_accounts() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_accounts", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":[""#.to_owned() + &format!("0x{:?}", address) + r#""],"id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -250,7 +250,7 @@ fn rpc_eth_block_number() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_blockNumber", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x0a","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -266,7 +266,7 @@ fn rpc_eth_balance() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x05","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -286,7 +286,7 @@ fn rpc_eth_balance_pending() {
 	// miner.
 	let response = r#"{"jsonrpc":"2.0","result":"0x00","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -302,7 +302,7 @@ fn rpc_eth_storage_at() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x0000000000000000000000000000000000000000000000000000000000000007","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -315,7 +315,7 @@ fn rpc_eth_transaction_count() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x00","id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -328,7 +328,7 @@ fn rpc_eth_block_transaction_count_by_hash() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":null,"id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -341,7 +341,7 @@ fn rpc_eth_transaction_count_by_number() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x00","id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -354,7 +354,7 @@ fn rpc_eth_transaction_count_by_number_pending() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x01","id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -375,7 +375,7 @@ fn rpc_eth_pending_transaction_by_hash() {
 		"params": ["0x0000000000000000000000000000000000000000000000000000000000000000"],
 		"id": 1
 	}"#;
-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }


@ -389,7 +389,7 @@ fn rpc_eth_uncle_count_by_block_hash() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":null,"id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -402,7 +402,7 @@ fn rpc_eth_uncle_count_by_block_number() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x00","id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -418,7 +418,7 @@ fn rpc_eth_code() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0xff21","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -453,7 +453,7 @@ fn rpc_eth_call_latest() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x1234ff","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -488,7 +488,7 @@ fn rpc_eth_call() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x1234ff","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -522,7 +522,7 @@ fn rpc_eth_call_default_block() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x1234ff","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -557,7 +557,7 @@ fn rpc_eth_estimate_gas() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0xff35","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -591,7 +591,7 @@ fn rpc_eth_estimate_gas_default_block() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0xff35","id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -625,7 +625,7 @@ fn rpc_eth_send_transaction() {

 	let response = r#"{"jsonrpc":"2.0","result":""#.to_owned() + format!("0x{:?}", t.hash()).as_ref() + r#"","id":1}"#;

-	assert_eq!(tester.io.handle_request(&request), Some(response));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response));

 	tester.miner.last_nonces.write().insert(address.clone(), U256::zero());

@ -642,7 +642,7 @@ fn rpc_eth_send_transaction() {

 	let response = r#"{"jsonrpc":"2.0","result":""#.to_owned() + format!("0x{:?}", t.hash()).as_ref() + r#"","id":1}"#;

-	assert_eq!(tester.io.handle_request(&request), Some(response));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response));
 }
 #[test]
 fn rpc_eth_send_transaction_with_bad_to() {
@ -663,7 +663,7 @@ fn rpc_eth_send_transaction_with_bad_to() {

 	let response = r#"{"jsonrpc":"2.0","error":{"code":-32602,"message":"Invalid params","data":null},"id":1}"#;

-	assert_eq!(tester.io.handle_request(&request), Some(response.into()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.into()));
 }


@ -685,7 +685,7 @@ fn rpc_eth_send_transaction_error() {
 	}"#;

 	let response = r#"{"jsonrpc":"2.0","error":{"code":-32020,"message":"Your account is locked. Unlock the account via CLI, personal_unlockAccount or use Trusted Signer.","data":"NotUnlocked"},"id":1}"#;
-	assert_eq!(tester.io.handle_request(&request), Some(response.into()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.into()));
 }

 #[test]
@ -718,7 +718,7 @@ fn rpc_eth_send_raw_transaction() {

 	let res = r#"{"jsonrpc":"2.0","result":""#.to_owned() + &format!("0x{:?}", t.hash()) + r#"","id":1}"#;

-	assert_eq!(tester.io.handle_request(&req), Some(res));
+	assert_eq!(tester.io.handle_request_sync(&req), Some(res));
 }

 #[test]
@ -760,7 +760,7 @@ fn rpc_eth_transaction_receipt() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":{"blockHash":"0xed76641c68a1c641aee09a94b3b471f4dc0316efe5ac19cf488e2674cf8d05b5","blockNumber":"0x04510c","contractAddress":null,"cumulativeGasUsed":"0x20","gasUsed":"0x10","logs":[{"address":"0x33990122638b9132ca29c723bdf037f1a891a70c","blockHash":"0xed76641c68a1c641aee09a94b3b471f4dc0316efe5ac19cf488e2674cf8d05b5","blockNumber":"0x04510c","data":"0x","logIndex":"0x01","topics":["0xa6697e974e6a320f454390be03f74955e8978f1a6971ea6730542e37b66179bc","0x4861736852656700000000000000000000000000000000000000000000000000"],"transactionHash":"0x0000000000000000000000000000000000000000000000000000000000000000","transactionIndex":"0x00","type":"mined"}],"transactionHash":"0x0000000000000000000000000000000000000000000000000000000000000000","transactionIndex":"0x00"},"id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -775,7 +775,7 @@ fn rpc_eth_transaction_receipt_null() {
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":null,"id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 // These tests are incorrect: their output is undefined as long as eth_getCompilers is [].
@ -788,7 +788,7 @@ fn rpc_eth_compilers() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_getCompilers", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":[],"id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[ignore]
@ -797,7 +797,7 @@ fn rpc_eth_compile_lll() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_compileLLL", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","error":{"code":-32603,"message":"Internal error","data":null},"id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[ignore]
@ -806,7 +806,7 @@ fn rpc_eth_compile_solidity() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_compileSolidity", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","error":{"code":-32603,"message":"Internal error","data":null},"id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[ignore]
@ -815,7 +815,7 @@ fn rpc_eth_compile_serpent() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_compileSerpent", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","error":{"code":-32603,"message":"Internal error","data":null},"id":1}"#;

-	assert_eq!(EthTester::default().io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(EthTester::default().io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -826,7 +826,7 @@ fn rpc_get_work_returns_no_work_if_cant_mine() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_getWork", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","error":{"code":-32001,"message":"Still syncing.","data":null},"id":1}"#;

-	assert_eq!(eth_tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(eth_tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -837,7 +837,7 @@ fn rpc_get_work_returns_correct_work_package() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_getWork", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":["0x3bbe93f74e7b97ae00784aeff8819c5cb600dd87e8b282a5d3446f3f871f0347","0x0000000000000000000000000000000000000000000000000000000000000000","0x0000800000000000000000000000000000000000000000000000000000000000","0x01"],"id":1}"#;

-	assert_eq!(eth_tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(eth_tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -851,7 +851,7 @@ fn rpc_get_work_should_not_return_block_number() {
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_getWork", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":["0x3bbe93f74e7b97ae00784aeff8819c5cb600dd87e8b282a5d3446f3f871f0347","0x0000000000000000000000000000000000000000000000000000000000000000","0x0000800000000000000000000000000000000000000000000000000000000000"],"id":1}"#;

-	assert_eq!(eth_tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(eth_tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -867,7 +867,7 @@ fn rpc_get_work_should_timeout() {
 		r#"{{"jsonrpc":"2.0","result":["0x{:?}","0x0000000000000000000000000000000000000000000000000000000000000000","0x0000800000000000000000000000000000000000000000000000000000000000","0x01"],"id":1}}"#,
 		hash,
 	);
-	assert_eq!(eth_tester.io.handle_request(request), Some(work_response.to_owned()));
+	assert_eq!(eth_tester.io.handle_request_sync(request), Some(work_response.to_owned()));

 	// Request with timeout of 0 seconds. This should work since we're disabling timeout.
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_getWork", "params": ["0"], "id": 1}"#;
@ -875,14 +875,14 @@ fn rpc_get_work_should_timeout() {
 		r#"{{"jsonrpc":"2.0","result":["0x{:?}","0x0000000000000000000000000000000000000000000000000000000000000000","0x0000800000000000000000000000000000000000000000000000000000000000","0x01"],"id":1}}"#,
 		hash,
 	);
-	assert_eq!(eth_tester.io.handle_request(request), Some(work_response.to_owned()));
+	assert_eq!(eth_tester.io.handle_request_sync(request), Some(work_response.to_owned()));

 	// Request with timeout of 10K seconds. This should work.
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_getWork", "params": ["10000"], "id": 1}"#;
-	assert_eq!(eth_tester.io.handle_request(request), Some(work_response.to_owned()));
+	assert_eq!(eth_tester.io.handle_request_sync(request), Some(work_response.to_owned()));

 	// Request with timeout of 10 seconds. This should fail.
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_getWork", "params": ["10"], "id": 1}"#;
 	let err_response = r#"{"jsonrpc":"2.0","error":{"code":-32003,"message":"Work has not changed.","data":null},"id":1}"#;
-	assert_eq!(eth_tester.io.handle_request(request), Some(err_response.to_owned()));
+	assert_eq!(eth_tester.io.handle_request_sync(request), Some(err_response.to_owned()));
 }
--- a/rpc/src/v1/tests/mocked/eth_signing.rs
+++ b/rpc/src/v1/tests/mocked/eth_signing.rs
@ -16,13 +16,13 @@

 use std::str::FromStr;
 use std::sync::Arc;
-use std::time::Duration;
 use jsonrpc_core::{IoHandler, to_value};
 use v1::impls::EthSigningQueueClient;
 use v1::traits::EthSigning;
 use v1::helpers::{ConfirmationsQueue, SigningQueue};
+use v1::types::{H256 as RpcH256, H520 as RpcH520};
 use v1::tests::helpers::TestMinerService;
-use util::{Address, FixedHash, Uint, U256, H256};
+use util::{Address, FixedHash, Uint, U256, H256, H520};
 use ethcore::account_provider::AccountProvider;
 use ethcore::client::TestBlockChainClient;
 use ethcore::transaction::{Transaction, Action};
@ -37,7 +37,7 @@ struct EthSigningTester {

 impl Default for EthSigningTester {
 	fn default() -> Self {
-		let queue = Arc::new(ConfirmationsQueue::with_timeout(Duration::from_millis(1)));
+		let queue = Arc::new(ConfirmationsQueue::default());
 		let client = Arc::new(TestBlockChainClient::default());
 		let miner = Arc::new(TestMinerService::default());
 		let accounts = Arc::new(AccountProvider::transient_provider());
@ -78,8 +78,13 @@ fn should_add_sign_to_queue() {
 	let response = r#"{"jsonrpc":"2.0","result":"0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","id":1}"#;

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	let async_result = tester.io.handle_request(&request).unwrap();
 	assert_eq!(tester.queue.requests().len(), 1);
+	// respond
+	tester.queue.request_confirmed(U256::from(1), Ok(to_value(&RpcH520::from(H520::default()))));
+	assert!(async_result.on_result(move |res| {
+		assert_eq!(res, response.to_owned());
+	}));
 }

 #[test]
@ -102,7 +107,7 @@ fn should_post_sign_to_queue() {
 	let response = r#"{"jsonrpc":"2.0","result":"0x01","id":1}"#;

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.to_owned()));
 	assert_eq!(tester.queue.requests().len(), 1);
 }

@ -120,7 +125,7 @@ fn should_check_status_of_request() {
 		],
 		"id": 1
 	}"#;
-	tester.io.handle_request(&request).expect("Sent");
+	tester.io.handle_request_sync(&request).expect("Sent");

 	// when
 	let request = r#"{
@ -132,7 +137,7 @@ fn should_check_status_of_request() {
 	let response = r#"{"jsonrpc":"2.0","result":null,"id":1}"#;

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.to_owned()));
 }

 #[test]
@ -149,8 +154,8 @@ fn should_check_status_of_request_when_its_resolved() {
 		],
 		"id": 1
 	}"#;
-	tester.io.handle_request(&request).expect("Sent");
-	tester.queue.request_confirmed(U256::from(1), to_value(&"Hello World!"));
+	tester.io.handle_request_sync(&request).expect("Sent");
+	tester.queue.request_confirmed(U256::from(1), Ok(to_value(&"Hello World!")));

 	// when
 	let request = r#"{
@ -162,7 +167,7 @@ fn should_check_status_of_request_when_its_resolved() {
 	let response = r#"{"jsonrpc":"2.0","result":"Hello World!","id":1}"#;

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.to_owned()));
 }

 #[test]
@ -186,7 +191,7 @@ fn should_sign_if_account_is_unlocked() {
 		"id": 1
 	}"#;
 	let response = r#"{"jsonrpc":"2.0","result":""#.to_owned() + format!("0x{}", signature).as_ref() + r#"","id":1}"#;
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.to_owned()));
 	assert_eq!(tester.queue.requests().len(), 0);
 }

@ -213,8 +218,13 @@ fn should_add_transaction_to_queue() {
 	let response = r#"{"jsonrpc":"2.0","result":"0x0000000000000000000000000000000000000000000000000000000000000000","id":1}"#;

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	let async_result = tester.io.handle_request(&request).unwrap();
 	assert_eq!(tester.queue.requests().len(), 1);
+	// respond
+	tester.queue.request_confirmed(U256::from(1), Ok(to_value(&RpcH256::from(H256::default()))));
+	assert!(async_result.on_result(move |res| {
+		assert_eq!(res, response.to_owned());
+	}));
 }

 #[test]
@ -251,5 +261,5 @@ fn should_dispatch_transaction_if_account_is_unlock() {
 	let response = r#"{"jsonrpc":"2.0","result":""#.to_owned() + format!("0x{:?}", t.hash()).as_ref() + r#"","id":1}"#;

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.to_owned()));
 }
--- a/rpc/src/v1/tests/mocked/ethcore.rs
+++ b/rpc/src/v1/tests/mocked/ethcore.rs
@ -80,7 +80,7 @@ fn rpc_ethcore_extra_data() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_extraData", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x01020304","id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -98,7 +98,7 @@ fn rpc_ethcore_default_extra_data() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_defaultExtraData", "params": [], "id": 1}"#;
 	let response = format!(r#"{{"jsonrpc":"2.0","result":"0x{}","id":1}}"#, misc::version_data().to_hex());

-	assert_eq!(io.handle_request(request), Some(response));
+	assert_eq!(io.handle_request_sync(request), Some(response));
 }

 #[test]
@ -113,7 +113,7 @@ fn rpc_ethcore_gas_floor_target() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_gasFloorTarget", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x3039","id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -128,7 +128,7 @@ fn rpc_ethcore_min_gas_price() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_minGasPrice", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x01312d00","id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -147,7 +147,7 @@ fn rpc_ethcore_dev_logs() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_devLogs", "params":[], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":["b","a"],"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -162,7 +162,7 @@ fn rpc_ethcore_dev_logs_levels() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_devLogsLevels", "params":[], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"rpc=trace","id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -177,7 +177,7 @@ fn rpc_ethcore_transactions_limit() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_transactionsLimit", "params":[], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":1024,"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -192,7 +192,7 @@ fn rpc_ethcore_net_chain() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_netChain", "params":[], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"testchain","id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -207,7 +207,7 @@ fn rpc_ethcore_net_peers() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_netPeers", "params":[], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":{"active":0,"connected":120,"max":50},"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -222,7 +222,7 @@ fn rpc_ethcore_net_port() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_netPort", "params":[], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":30303,"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -237,7 +237,7 @@ fn rpc_ethcore_rpc_settings() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_rpcSettings", "params":[], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":{"enabled":true,"interface":"all","port":8545},"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -252,7 +252,7 @@ fn rpc_ethcore_node_name() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_nodeName", "params":[], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"mynode","id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -269,7 +269,7 @@ fn rpc_ethcore_unsigned_transactions_count() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_unsignedTransactionsCount", "params":[], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":0,"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -284,5 +284,5 @@ fn rpc_ethcore_unsigned_transactions_count_when_signer_disabled() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_unsignedTransactionsCount", "params":[], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","error":{"code":-32030,"message":"Trusted Signer is disabled. This API is not available.","data":null},"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }
--- a/rpc/src/v1/tests/mocked/ethcore_set.rs
+++ b/rpc/src/v1/tests/mocked/ethcore_set.rs
@ -53,7 +53,7 @@ fn rpc_ethcore_set_min_gas_price() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_setMinGasPrice", "params":["0xcd1722f3947def4cf144679da39c4c32bdc35681"], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 	assert_eq!(miner.minimal_gas_price(), U256::from_str("cd1722f3947def4cf144679da39c4c32bdc35681").unwrap());
 }

@ -68,7 +68,7 @@ fn rpc_ethcore_set_gas_floor_target() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_setGasFloorTarget", "params":["0xcd1722f3947def4cf144679da39c4c32bdc35681"], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 	assert_eq!(miner.gas_floor_target(), U256::from_str("cd1722f3947def4cf144679da39c4c32bdc35681").unwrap());
 }

@ -83,7 +83,7 @@ fn rpc_ethcore_set_extra_data() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_setExtraData", "params":["0xcd1722f3947def4cf144679da39c4c32bdc35681"], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 	assert_eq!(miner.extra_data(), "cd1722f3947def4cf144679da39c4c32bdc35681".from_hex().unwrap());
 }

@ -98,7 +98,7 @@ fn rpc_ethcore_set_author() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_setAuthor", "params":["0xcd1722f3947def4cf144679da39c4c32bdc35681"], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 	assert_eq!(miner.author(), Address::from_str("cd1722f3947def4cf144679da39c4c32bdc35681").unwrap());
 }

@ -113,6 +113,6 @@ fn rpc_ethcore_set_transactions_limit() {
 	let request = r#"{"jsonrpc": "2.0", "method": "ethcore_setTransactionsLimit", "params":[10240240], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 	assert_eq!(miner.transactions_limit(), 10_240_240);
 }
--- a/rpc/src/v1/tests/mocked/net.rs
+++ b/rpc/src/v1/tests/mocked/net.rs
@ -36,7 +36,7 @@ fn rpc_net_version() {
 	let request = r#"{"jsonrpc": "2.0", "method": "net_version", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"3","id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -49,7 +49,7 @@ fn rpc_net_peer_count() {
 	let request = r#"{"jsonrpc": "2.0", "method": "net_peerCount", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x78","id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -62,5 +62,5 @@ fn rpc_net_listening() {
 	let request = r#"{"jsonrpc": "2.0", "method": "net_listening", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }
--- a/rpc/src/v1/tests/mocked/personal.rs
+++ b/rpc/src/v1/tests/mocked/personal.rs
@ -76,7 +76,7 @@ fn should_return_false_if_signer_is_disabled() {


 	// then
-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -90,7 +90,7 @@ fn should_return_port_number_if_signer_is_enabled() {


 	// then
-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -100,7 +100,7 @@ fn accounts() {
 	let request = r#"{"jsonrpc": "2.0", "method": "personal_listAccounts", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":[""#.to_owned() + &format!("0x{:?}", address) + r#""],"id":1}"#;

-	assert_eq!(tester.io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -108,7 +108,7 @@ fn new_account() {
 	let tester = setup(None);
 	let request = r#"{"jsonrpc": "2.0", "method": "personal_newAccount", "params": ["pass"], "id": 1}"#;

-	let res = tester.io.handle_request(request);
+	let res = tester.io.handle_request_sync(request);

 	let accounts = tester.accounts.accounts().unwrap();
 	assert_eq!(accounts.len(), 1);
@ -131,7 +131,7 @@ fn should_be_able_to_get_account_info() {
 	tester.accounts.set_account_meta(address.clone(), "{foo: 69}".to_owned()).unwrap();

 	let request = r#"{"jsonrpc": "2.0", "method": "personal_accountsInfo", "params": [], "id": 1}"#;
-	let res = tester.io.handle_request(request);
+	let res = tester.io.handle_request_sync(request);
 	let response = format!("{{\"jsonrpc\":\"2.0\",\"result\":{{\"0x{}\":{{\"meta\":\"{{foo: 69}}\",\"name\":\"Test\",\"uuid\":\"{}\"}}}},\"id\":1}}", address.hex(), uuid);
 	assert_eq!(res, Some(response));
 }
@ -146,13 +146,13 @@ fn should_be_able_to_set_name() {

 	let request = format!(r#"{{"jsonrpc": "2.0", "method": "personal_setAccountName", "params": ["0x{}", "Test"], "id": 1}}"#, address.hex());
 	let response = r#"{"jsonrpc":"2.0","result":null,"id":1}"#;
-	let res = tester.io.handle_request(&request);
+	let res = tester.io.handle_request_sync(&request);
 	assert_eq!(res, Some(response.into()));

 	let uuid = tester.accounts.accounts_info().unwrap().get(&address).unwrap().uuid.as_ref().unwrap().clone();

 	let request = r#"{"jsonrpc": "2.0", "method": "personal_accountsInfo", "params": [], "id": 1}"#;
-	let res = tester.io.handle_request(request);
+	let res = tester.io.handle_request_sync(request);
 	let response = format!("{{\"jsonrpc\":\"2.0\",\"result\":{{\"0x{}\":{{\"meta\":\"{{}}\",\"name\":\"Test\",\"uuid\":\"{}\"}}}},\"id\":1}}", address.hex(), uuid);
 	assert_eq!(res, Some(response));
 }
@ -167,13 +167,13 @@ fn should_be_able_to_set_meta() {

 	let request = format!(r#"{{"jsonrpc": "2.0", "method": "personal_setAccountMeta", "params": ["0x{}", "{{foo: 69}}"], "id": 1}}"#, address.hex());
 	let response = r#"{"jsonrpc":"2.0","result":null,"id":1}"#;
-	let res = tester.io.handle_request(&request);
+	let res = tester.io.handle_request_sync(&request);
 	assert_eq!(res, Some(response.into()));

 	let uuid = tester.accounts.accounts_info().unwrap().get(&address).unwrap().uuid.as_ref().unwrap().clone();

 	let request = r#"{"jsonrpc": "2.0", "method": "personal_accountsInfo", "params": [], "id": 1}"#;
-	let res = tester.io.handle_request(request);
+	let res = tester.io.handle_request_sync(request);
 	let response = format!("{{\"jsonrpc\":\"2.0\",\"result\":{{\"0x{}\":{{\"meta\":\"{{foo: 69}}\",\"name\":\"{}\",\"uuid\":\"{}\"}}}},\"id\":1}}", address.hex(), uuid, uuid);
 	assert_eq!(res, Some(response));
 }
@ -197,7 +197,7 @@ fn sign_and_send_transaction_with_invalid_password() {

 	let response = r#"{"jsonrpc":"2.0","error":{"code":-32021,"message":"Account password is invalid or account does not exist.","data":"SStore(InvalidPassword)"},"id":1}"#;

-	assert_eq!(tester.io.handle_request(request.as_ref()), Some(response.into()));
+	assert_eq!(tester.io.handle_request_sync(request.as_ref()), Some(response.into()));
 }

 #[test]
@ -232,7 +232,7 @@ fn sign_and_send_transaction() {

 	let response = r#"{"jsonrpc":"2.0","result":""#.to_owned() + format!("0x{:?}", t.hash()).as_ref() + r#"","id":1}"#;

-	assert_eq!(tester.io.handle_request(request.as_ref()), Some(response));
+	assert_eq!(tester.io.handle_request_sync(request.as_ref()), Some(response));

 	tester.miner.last_nonces.write().insert(address.clone(), U256::zero());

@ -250,5 +250,5 @@ fn sign_and_send_transaction() {

 	let response = r#"{"jsonrpc":"2.0","result":""#.to_owned() + format!("0x{:?}", t.hash()).as_ref() + r#"","id":1}"#;

-	assert_eq!(tester.io.handle_request(request.as_ref()), Some(response));
+	assert_eq!(tester.io.handle_request_sync(request.as_ref()), Some(response));
 }
--- a/rpc/src/v1/tests/mocked/personal_signer.rs
+++ b/rpc/src/v1/tests/mocked/personal_signer.rs
@ -79,8 +79,8 @@ fn should_return_list_of_items_to_confirm() {
 		value: U256::from(1),
 		data: vec![],
 		nonce: None,
-	}));
-	tester.queue.add_request(ConfirmationPayload::Sign(1.into(), 5.into()));
+	})).unwrap();
+	tester.queue.add_request(ConfirmationPayload::Sign(1.into(), 5.into())).unwrap();

 	// when
 	let request = r#"{"jsonrpc":"2.0","method":"personal_requestsToConfirm","params":[],"id":1}"#;
@ -92,7 +92,7 @@ fn should_return_list_of_items_to_confirm() {
 	);

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.to_owned()));
 }


@ -108,7 +108,7 @@ fn should_reject_transaction_from_queue_without_dispatching() {
 		value: U256::from(1),
 		data: vec![],
 		nonce: None,
-	}));
+	})).unwrap();
 	assert_eq!(tester.queue.requests().len(), 1);

 	// when
@ -116,7 +116,7 @@ fn should_reject_transaction_from_queue_without_dispatching() {
 	let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.to_owned()));
 	assert_eq!(tester.queue.requests().len(), 0);
 	assert_eq!(tester.miner.imported_transactions.lock().len(), 0);
 }
@ -133,7 +133,7 @@ fn should_not_remove_transaction_if_password_is_invalid() {
 		value: U256::from(1),
 		data: vec![],
 		nonce: None,
-	}));
+	})).unwrap();
 	assert_eq!(tester.queue.requests().len(), 1);

 	// when
@ -141,7 +141,7 @@ fn should_not_remove_transaction_if_password_is_invalid() {
 	let response = r#"{"jsonrpc":"2.0","error":{"code":-32021,"message":"Account password is invalid or account does not exist.","data":"SStore(InvalidAccount)"},"id":1}"#;

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.to_owned()));
 	assert_eq!(tester.queue.requests().len(), 1);
 }

@ -149,7 +149,7 @@ fn should_not_remove_transaction_if_password_is_invalid() {
 fn should_not_remove_sign_if_password_is_invalid() {
 	// given
 	let tester = signer_tester();
-	tester.queue.add_request(ConfirmationPayload::Sign(0.into(), 5.into()));
+	tester.queue.add_request(ConfirmationPayload::Sign(0.into(), 5.into())).unwrap();
 	assert_eq!(tester.queue.requests().len(), 1);

 	// when
@ -157,7 +157,7 @@ fn should_not_remove_sign_if_password_is_invalid() {
 	let response = r#"{"jsonrpc":"2.0","error":{"code":-32021,"message":"Account password is invalid or account does not exist.","data":"SStore(InvalidAccount)"},"id":1}"#;

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.to_owned()));
 	assert_eq!(tester.queue.requests().len(), 1);
 }

@ -175,7 +175,7 @@ fn should_confirm_transaction_and_dispatch() {
 		value: U256::from(1),
 		data: vec![],
 		nonce: None,
-	}));
+	})).unwrap();

 	let t = Transaction {
 		nonce: U256::zero(),
@ -201,7 +201,7 @@ fn should_confirm_transaction_and_dispatch() {
 	let response = r#"{"jsonrpc":"2.0","result":""#.to_owned() + format!("0x{:?}", t.hash()).as_ref() + r#"","id":1}"#;

 	// then
-	assert_eq!(tester.io.handle_request(&request), Some(response.to_owned()));
+	assert_eq!(tester.io.handle_request_sync(&request), Some(response.to_owned()));
 	assert_eq!(tester.queue.requests().len(), 0);
 	assert_eq!(tester.miner.imported_transactions.lock().len(), 1);
 }
--- a/rpc/src/v1/tests/mocked/rpc.rs
+++ b/rpc/src/v1/tests/mocked/rpc.rs
@ -36,7 +36,7 @@ fn modules() {
 	let request = r#"{"jsonrpc": "2.0", "method": "modules", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":{"rpc":"1.0","web3":"1.0"},"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -48,5 +48,5 @@ fn rpc_modules() {
 	let request = r#"{"jsonrpc": "2.0", "method": "rpc_modules", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":{"ethcore":"1.0","rpc":"1.0","web3":"1.0"},"id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }
--- a/rpc/src/v1/tests/mocked/web3.rs
+++ b/rpc/src/v1/tests/mocked/web3.rs
@ -29,7 +29,7 @@ fn rpc_web3_version() {
 	let request = r#"{"jsonrpc": "2.0", "method": "web3_clientVersion", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"VER","id":1}"#.to_owned().replace("VER", v.as_ref());

-	assert_eq!(io.handle_request(request), Some(response));
+	assert_eq!(io.handle_request_sync(request), Some(response));
 }

 #[test]
@ -41,7 +41,7 @@ fn rpc_web3_sha3() {
 	let request = r#"{"jsonrpc": "2.0", "method": "web3_sha3", "params": ["0x00"], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0xbc36789e7a1e281436464229828f817d6612f7b477d66591ff96a9e064bcc98a","id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }

 #[test]
@ -53,5 +53,5 @@ fn rpc_web3_sha3_wiki() {
 	let request = r#"{"jsonrpc": "2.0", "method": "web3_sha3", "params": ["0x68656c6c6f20776f726c64"], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":"0x47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad","id":1}"#;

-	assert_eq!(io.handle_request(request), Some(response.to_owned()));
+	assert_eq!(io.handle_request_sync(request), Some(response.to_owned()));
 }
--- a/rpc/src/v1/traits/eth.rs
+++ b/rpc/src/v1/traits/eth.rs
@ -204,7 +204,7 @@ pub trait EthFilter: Sized + Send + Sync + 'static {
 /// Signing methods implementation relying on unlocked accounts.
 pub trait EthSigning: Sized + Send + Sync + 'static {
 	/// Signs the data with given address signature.
-	fn sign(&self, _: Params) -> Result<Value, Error>;
+	fn sign(&self, _: Params, _: Ready);

 	/// Posts sign request asynchronously.
 	/// Will return a confirmation ID for later use with check_transaction.
@ -214,7 +214,7 @@ pub trait EthSigning: Sized + Send + Sync + 'static {
 	/// transaction hash.
 	/// If it cannot yet be signed, it will return a transaction ID for
 	/// later use with check_transaction.
-	fn send_transaction(&self, _: Params) -> Result<Value, Error>;
+	fn send_transaction(&self, _: Params, _: Ready);

 	/// Posts transaction asynchronously.
 	/// Will return a transaction ID for later use with check_transaction.
@ -230,8 +230,8 @@ pub trait EthSigning: Sized + Send + Sync + 'static {
 	/// Should be used to convert object to io delegate.
 	fn to_delegate(self) -> IoDelegate<Self> {
 		let mut delegate = IoDelegate::new(Arc::new(self));
-		delegate.add_method("eth_sign", EthSigning::sign);
-		delegate.add_method("eth_sendTransaction", EthSigning::send_transaction);
+		delegate.add_async_method("eth_sign", EthSigning::sign);
+		delegate.add_async_method("eth_sendTransaction", EthSigning::send_transaction);
 		delegate.add_method("eth_postSign", EthSigning::post_sign);
 		delegate.add_method("eth_postTransaction", EthSigning::post_transaction);
 		delegate.add_method("eth_checkRequest", EthSigning::check_request);
--- a/rpc/src/v1/types/trace.rs
+++ b/rpc/src/v1/types/trace.rs
@ -549,7 +549,7 @@ mod tests {
 			block_hash: H256::from(14),
 		};
 		let serialized = serde_json::to_string(&t).unwrap();
-		assert_eq!(serialized, r#"{"action":{"call":{"from":"0x0000000000000000000000000000000000000004","to":"0x0000000000000000000000000000000000000005","value":"0x06","gas":"0x07","input":"0x1234","callType":{"call":[]}}},"result":{"call":{"gasUsed":"0x08","output":"0x5678"}},"traceAddress":["0x0a"],"subtraces":"0x01","transactionPosition":"0x0b","transactionHash":"0x000000000000000000000000000000000000000000000000000000000000000c","blockNumber":"0x0d","blockHash":"0x000000000000000000000000000000000000000000000000000000000000000e"}"#);
+		assert_eq!(serialized, r#"{"action":{"call":{"from":"0x0000000000000000000000000000000000000004","to":"0x0000000000000000000000000000000000000005","value":"0x06","gas":"0x07","input":"0x1234","callType":"call"}},"result":{"call":{"gasUsed":"0x08","output":"0x5678"}},"traceAddress":["0x0a"],"subtraces":"0x01","transactionPosition":"0x0b","transactionHash":"0x000000000000000000000000000000000000000000000000000000000000000c","blockNumber":"0x0d","blockHash":"0x000000000000000000000000000000000000000000000000000000000000000e"}"#);
 	}

 	#[test]
@ -614,7 +614,7 @@ mod tests {
 			}
 		]);
 		let serialized = serde_json::to_string(&t).unwrap();
-		assert_eq!(serialized, r#"{"0x000000000000000000000000000000000000002a":{"balance":{"=":[]},"nonce":{"+":"0x01"},"code":{"=":[]},"storage":{"0x000000000000000000000000000000000000000000000000000000000000002a":{"=":[]}}},"0x0000000000000000000000000000000000000045":{"balance":{"=":[]},"nonce":{"*":{"from":"0x01","to":"0x00"}},"code":{"-":"0x60"},"storage":{}}}"#);
+		assert_eq!(serialized, r#"{"0x000000000000000000000000000000000000002a":{"balance":"=","nonce":{"+":"0x01"},"code":"=","storage":{"0x000000000000000000000000000000000000000000000000000000000000002a":"="}},"0x0000000000000000000000000000000000000045":{"balance":"=","nonce":{"*":{"from":"0x01","to":"0x00"}},"code":{"-":"0x60"},"storage":{}}}"#);
 	}

 	#[test]
@ -634,7 +634,7 @@ mod tests {
 		})];

 		let serialized = serde_json::to_string(&actions).unwrap();
-		assert_eq!(serialized, r#"[{"call":{"from":"0x0000000000000000000000000000000000000001","to":"0x0000000000000000000000000000000000000002","value":"0x03","gas":"0x04","input":"0x1234","callType":{"call":[]}}},{"create":{"from":"0x0000000000000000000000000000000000000005","value":"0x06","gas":"0x07","init":"0x5678"}}]"#);
+		assert_eq!(serialized, r#"[{"call":{"from":"0x0000000000000000000000000000000000000001","to":"0x0000000000000000000000000000000000000002","value":"0x03","gas":"0x04","input":"0x1234","callType":"call"}},{"create":{"from":"0x0000000000000000000000000000000000000005","value":"0x06","gas":"0x07","init":"0x5678"}}]"#);
 	}

 	#[test]
@ -654,6 +654,6 @@ mod tests {
 		];

 		let serialized = serde_json::to_string(&results).unwrap();
-		assert_eq!(serialized, r#"[{"call":{"gasUsed":"0x01","output":"0x1234"}},{"create":{"gasUsed":"0x02","code":"0x4556","address":"0x0000000000000000000000000000000000000003"}},{"failedCall":[]},{"failedCreate":[]}]"#);
+		assert_eq!(serialized, r#"[{"call":{"gasUsed":"0x01","output":"0x1234"}},{"create":{"gasUsed":"0x02","code":"0x4556","address":"0x0000000000000000000000000000000000000003"}},"failedCall","failedCreate"]"#);
 	}
 }
--- a/signer/Cargo.toml
+++ b/signer/Cargo.toml
@ -12,7 +12,7 @@ rustc_version = "0.1"

 [dependencies]
 rand = "0.3.14"
-jsonrpc-core = "2.1"
+jsonrpc-core = "3.0"
 log = "0.3"
 env_logger = "0.3"
 ws = { git = "https://github.com/ethcore/ws-rs.git", branch = "mio-upstream-stable" }
--- a/signer/src/ws_server/session.rs
+++ b/signer/src/ws_server/session.rs
@ -22,7 +22,7 @@ use std::path::{PathBuf, Path};
 use std::sync::Arc;
 use std::str::FromStr;
 use jsonrpc_core::IoHandler;
-use util::H256;
+use util::{H256, Mutex};

 #[cfg(feature = "ui")]
 mod signer {
@ -95,7 +95,7 @@ fn add_headers(mut response: ws::Response, mime: &str) -> ws::Response {
 }

 pub struct Session {
-	out: ws::Sender,
+	out: Arc<Mutex<ws::Sender>>,
 	skip_origin_validation: bool,
 	self_origin: String,
 	authcodes_path: PathBuf,
@ -145,12 +145,16 @@ impl ws::Handler for Session {

 	fn on_message(&mut self, msg: ws::Message) -> ws::Result<()> {
 		let req = try!(msg.as_text());
-		match self.handler.handle_request(req) {
-			Some(res) => {
-				self.out.send(res)
-			},
-			None => Ok(()),
+		if let Some(async) = self.handler.handle_request(req) {
+			let out = self.out.clone();
+			async.on_result(move |result| {
+				let res = out.lock().send(result);
+				if let Err(e) = res {
+					warn!(target: "signer", "Error while sending response: {:?}", e);
+				}
+			});
 		}
+		Ok(())
 	}
 }

@ -177,7 +181,7 @@ impl ws::Factory for Factory {

 	fn connection_made(&mut self, sender: ws::Sender) -> Self::Handler {
 		Session {
-			out: sender,
+			out: Arc::new(Mutex::new(sender)),
 			handler: self.handler.clone(),
 			skip_origin_validation: self.skip_origin_validation,
 			self_origin: self.self_origin.clone(),
--- a/stratum/Cargo.toml
+++ b/stratum/Cargo.toml
@ -12,7 +12,7 @@ ethcore-ipc-codegen = { path = "../ipc/codegen" }
 [dependencies]
 log = "0.3"
 json-tcp-server = { git = "https://github.com/ethcore/json-tcp-server" }
-jsonrpc-core = "2.1"
+jsonrpc-core = "3.0"
 mio = { git = "https://github.com/ethcore/mio", branch = "v0.5.x" }
 ethcore-util = { path = "../util" }
 ethcore-devtools = { path = "../devtools" }
--- a/stratum/src/lib.rs
+++ b/stratum/src/lib.rs
@ -108,15 +108,15 @@ impl Stratum {
 				Ok(val) => val,
 				Err(e) => {
 					warn!(target: "stratum", "Invalid payload: '{}' ({:?})", &initial, e);
-					try!(to_value(&[0u8; 0]))
+					to_value(&[0u8; 0])
 				},
 			},
-			None => try!(to_value(&[0u8; 0])),
+			None => to_value(&[0u8; 0]),
 		})
 	}

 	fn authorize(&self, params: Params) -> std::result::Result<jsonrpc_core::Value, jsonrpc_core::Error> {
-		from_params::<(String, String)>(params).and_then(|(worker_id, secret)|{
+		from_params::<(String, String)>(params).map(|(worker_id, secret)|{
 			if let Some(valid_secret) = self.secret {
 				let hash = secret.sha3();
 				if hash != valid_secret {
--- a/test.sh
+++ b/test.sh
@ -2,17 +2,22 @@
 # Running Parity Full Test Sute

 FEATURES="json-tests ipc"
+OPTIONS="--release"

 case $1 in
    --no-json)
    FEATURES="ipc"
    shift # past argument=value
    ;;
+	--no-release)
+	OPTIONS=""
+	shift
+	;;
    *)
            # unknown option
    ;;
 esac

 . ./scripts/targets.sh
-cargo test --release --features "$FEATURES" $TARGETS $1 \
+cargo test $OPTIONS --features "$FEATURES" $TARGETS $1 \