openethereum/rpc_client/src/client.rs

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Rust
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extern crate jsonrpc_core;
use std::fmt::{Debug, Formatter, Error as FmtError};
use std::io::{BufReader, BufRead};
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use std::sync::Arc;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::collections::BTreeMap;
use std::thread;
use std::time;
use std::path::PathBuf;
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use util::{Hashable, Mutex};
use url::Url;
use std::fs::File;
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use ws::{
self,
Request,
Handler,
Sender,
Handshake,
Error as WsError,
ErrorKind as WsErrorKind,
Message,
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Result as WsResult,
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};
use serde::Deserialize;
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use serde_json::{
self as json,
Value as JsonValue,
Error as JsonError,
};
use futures::{BoxFuture, Canceled, Complete, Future, oneshot, done};
use jsonrpc_core::{Id, Version, Params, Error as JsonRpcError};
use jsonrpc_core::request::MethodCall;
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use jsonrpc_core::response::{Output, Success, Failure};
/// The actual websocket connection handler, passed into the
/// event loop of ws-rs
struct RpcHandler {
pending: Pending,
// Option is used here as temporary storage until connection
// is setup and the values are moved into the new `Rpc`
complete: Option<Complete<Result<Rpc, RpcError>>>,
auth_code: String,
out: Option<Sender>,
}
impl RpcHandler {
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fn new(
out: Sender,
auth_code: String,
complete: Complete<Result<Rpc, RpcError>>
) -> Self {
RpcHandler {
out: Some(out),
auth_code: auth_code,
pending: Pending::new(),
complete: Some(complete),
}
}
}
impl Handler for RpcHandler {
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fn build_request(&mut self, url: &Url) -> WsResult<Request> {
match Request::from_url(url) {
Ok(mut r) => {
let timestamp = time::UNIX_EPOCH.elapsed().map_err(|err| {
WsError::new(WsErrorKind::Internal, format!("{}", err))
})?;
let secs = timestamp.as_secs();
let hashed = format!("{}:{}", self.auth_code, secs).sha3();
let proto = format!("{:?}_{}", hashed, secs);
r.add_protocol(&proto);
Ok(r)
},
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Err(e) =>
Err(WsError::new(WsErrorKind::Internal, format!("{}", e))),
}
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}
fn on_error(&mut self, err: WsError) {
match self.complete.take() {
Some(c) => match c.send(Err(RpcError::WsError(err))) {
Ok(_) => {},
Err(_) => warn!(target: "rpc-client", "Unable to notify about error."),
},
None => warn!(target: "rpc-client", "unexpected error: {}", err),
}
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}
fn on_open(&mut self, _: Handshake) -> WsResult<()> {
match (self.complete.take(), self.out.take()) {
(Some(c), Some(out)) => {
let res = c.send(Ok(Rpc {
out: out,
counter: AtomicUsize::new(0),
pending: self.pending.clone(),
}));
if let Err(_) = res {
warn!(target: "rpc-client", "Unable to open a connection.")
}
Ok(())
},
_ => {
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let msg = format!("on_open called twice");
Err(WsError::new(WsErrorKind::Internal, msg))
}
}
}
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fn on_message(&mut self, msg: Message) -> WsResult<()> {
let ret: Result<JsonValue, JsonRpcError>;
let response_id;
let string = &msg.to_string();
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match json::from_str::<Output>(&string) {
Ok(Output::Success(Success { result, id: Id::Num(id), .. })) =>
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{
ret = Ok(result);
response_id = id as usize;
}
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Ok(Output::Failure(Failure { error, id: Id::Num(id), .. })) => {
ret = Err(error);
response_id = id as usize;
}
Err(e) => {
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warn!(
target: "rpc-client",
"recieved invalid message: {}\n {:?}",
string,
e
);
return Ok(())
},
_ => {
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warn!(
target: "rpc-client",
"recieved invalid message: {}",
string
);
return Ok(())
}
}
match self.pending.remove(response_id) {
Some(c) => if let Err(_) = c.send(ret.map_err(|err| RpcError::JsonRpc(err))) {
warn!(target: "rpc-client", "Unable to send response.")
},
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None => warn!(
target: "rpc-client",
"warning: unexpected id: {}",
response_id
),
}
Ok(())
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}
}
/// Keeping track of issued requests to be matched up with responses
#[derive(Clone)]
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struct Pending(
Arc<Mutex<BTreeMap<usize, Complete<Result<JsonValue, RpcError>>>>>
);
impl Pending {
fn new() -> Self {
Pending(Arc::new(Mutex::new(BTreeMap::new())))
}
fn insert(&mut self, k: usize, v: Complete<Result<JsonValue, RpcError>>) {
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self.0.lock().insert(k, v);
}
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fn remove(
&mut self,
k: usize
) -> Option<Complete<Result<JsonValue, RpcError>>> {
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self.0.lock().remove(&k)
}
}
fn get_authcode(path: &PathBuf) -> Result<String, RpcError> {
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if let Ok(fd) = File::open(path) {
if let Some(Ok(line)) = BufReader::new(fd).lines().next() {
let mut parts = line.split(';');
let token = parts.next();
if let Some(code) = token {
return Ok(code.into());
}
}
}
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Err(RpcError::NoAuthCode)
}
/// The handle to the connection
pub struct Rpc {
out: Sender,
counter: AtomicUsize,
pending: Pending,
}
impl Rpc {
/// Blocking, returns a new initialized connection or RpcError
pub fn new(url: &str, authpath: &PathBuf) -> Result<Self, RpcError> {
let rpc = Self::connect(url, authpath).map(|rpc| rpc).wait()?;
rpc
}
/// Non-blocking, returns a future
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pub fn connect(
url: &str, authpath: &PathBuf
) -> BoxFuture<Result<Self, RpcError>, Canceled> {
let (c, p) = oneshot::<Result<Self, RpcError>>();
match get_authcode(authpath) {
Err(e) => return done(Ok(Err(e))).boxed(),
Ok(code) => {
let url = String::from(url);
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// The ws::connect takes a FnMut closure, which means c cannot
// be moved into it, since it's consumed on complete.
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// Therefore we wrap it in an option and pick it out once.
let mut once = Some(c);
thread::spawn(move || {
let conn = ws::connect(url, |out| {
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// this will panic if the closure is called twice,
// which it should never be.
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let c = once.take()
.expect("connection closure called only once");
RpcHandler::new(out, code.clone(), c)
});
match conn {
Err(err) => {
// since ws::connect is only called once, it cannot
// both fail and succeed.
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let c = once.take()
.expect("connection closure called only once");
let _ = c.send(Err(RpcError::WsError(err)));
},
// c will complete on the `on_open` event in the Handler
_ => ()
}
});
p.boxed()
}
}
}
/// Non-blocking, returns a future of the request response
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pub fn request<T>(
&mut self, method: &'static str, params: Vec<JsonValue>
) -> BoxFuture<Result<T, RpcError>, Canceled>
where T: Deserialize + Send + Sized {
let (c, p) = oneshot::<Result<JsonValue, RpcError>>();
let id = self.counter.fetch_add(1, Ordering::Relaxed);
self.pending.insert(id, c);
let request = MethodCall {
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jsonrpc: Some(Version::V2),
method: method.to_owned(),
params: Some(Params::Array(params)),
id: Id::Num(id as u64),
};
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let serialized = json::to_string(&request)
.expect("request is serializable");
let _ = self.out.send(serialized);
p.map(|result| {
match result {
Ok(json) => {
let t: T = json::from_value(json)?;
Ok(t)
},
Err(err) => Err(err)
}
}).boxed()
}
}
pub enum RpcError {
WrongVersion(String),
ParseError(JsonError),
MalformedResponse(String),
JsonRpc(JsonRpcError),
WsError(WsError),
Canceled(Canceled),
UnexpectedId,
NoAuthCode,
}
impl Debug for RpcError {
fn fmt(&self, f: &mut Formatter) -> Result<(), FmtError> {
match *self {
RpcError::WrongVersion(ref s)
=> write!(f, "Expected version 2.0, got {}", s),
RpcError::ParseError(ref err)
=> write!(f, "ParseError: {}", err),
RpcError::MalformedResponse(ref s)
=> write!(f, "Malformed response: {}", s),
RpcError::JsonRpc(ref json)
=> write!(f, "JsonRpc error: {:?}", json),
RpcError::WsError(ref s)
=> write!(f, "Websocket error: {}", s),
RpcError::Canceled(ref s)
=> write!(f, "Futures error: {:?}", s),
RpcError::UnexpectedId
=> write!(f, "Unexpected response id"),
RpcError::NoAuthCode
=> write!(f, "No authcodes available"),
}
}
}
impl From<JsonError> for RpcError {
fn from(err: JsonError) -> RpcError {
RpcError::ParseError(err)
}
}
impl From<WsError> for RpcError {
fn from(err: WsError) -> RpcError {
RpcError::WsError(err)
}
}
impl From<Canceled> for RpcError {
fn from(err: Canceled) -> RpcError {
RpcError::Canceled(err)
}
}