Squashed: Public Node

js/src/api/api.js

@@ -23,6 +23,7 @@ import { Db, Eth, Parity, Net, Personal, Shh, Signer, Trace, Web3 } from './rpc'
 import Subscriptions from './subscriptions';
 import util from './util';
 import { isFunction } from './util/types';
+import { LocalAccountsMiddleware } from './local';
 
 export default class Api extends EventEmitter {
   constructor (transport) {
@@ -45,6 +46,21 @@ export default class Api extends EventEmitter {
     this._web3 = new Web3(transport);
 
     this._subscriptions = new Subscriptions(this);
+
+    // Doing a request here in test env would cause an error
+    if (process.env.NODE_ENV !== 'test') {
+      const middleware = this.parity
+        .nodeKind()
+        .then((nodeKind) => {
+          if (nodeKind.availability === 'public') {
+            return new LocalAccountsMiddleware(transport);
+          }
+
+          return null;
+        });
+
+      transport.addMiddleware(middleware);
+    }
   }
 
   get db () {

js/src/api/local/accounts/account.js

@@ -0,0 +1,95 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import { keythereum } from '../ethkey';
+
+export default class Account {
+  constructor (persist, data) {
+    const {
+      keyObject,
+      meta = {},
+      name = ''
+    } = data;
+
+    this._persist = persist;
+    this._keyObject = keyObject;
+    this._name = name;
+    this._meta = meta;
+  }
+
+  isValidPassword (password) {
+    try {
+      keythereum.recover(Buffer.from(password), this._keyObject);
+      return true;
+    } catch (e) {
+      return false;
+    }
+  }
+
+  get address () {
+    return `0x${this._keyObject.address.toLowerCase()}`;
+  }
+
+  get name () {
+    return this._name;
+  }
+
+  set name (name) {
+    this._name = name;
+
+    this._persist();
+  }
+
+  get meta () {
+    return JSON.stringify(this._meta);
+  }
+
+  set meta (meta) {
+    this._meta = JSON.parse(meta);
+
+    this._persist();
+  }
+
+  get uuid () {
+    return this._keyObject.id;
+  }
+
+  decryptPrivateKey (password) {
+    return keythereum.recover(Buffer.from(password), this._keyObject);
+  }
+
+  static fromPrivateKey (persist, key, password) {
+    const iv = keythereum.crypto.randomBytes(16);
+    const salt = keythereum.crypto.randomBytes(32);
+
+    // Keythereum will fail if `password` is an empty string
+    password = Buffer.from(password);
+
+    const keyObject = keythereum.dump(password, key, salt, iv);
+
+    const account = new Account(persist, { keyObject });
+
+    return account;
+  }
+
+  toJSON () {
+    return {
+      keyObject: this._keyObject,
+      name: this._name,
+      meta: this._meta
+    };
+  }
+}

js/src/api/local/accounts/accounts.js

@@ -0,0 +1,120 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import Account from './account';
+import localStore from 'store';
+import { debounce } from 'lodash';
+
+const NULL_ADDRESS = '0x0000000000000000000000000000000000000000';
+const LS_STORE_KEY = '_parity::localAccounts';
+
+export default class Accounts {
+  constructor (data = localStore.get(LS_STORE_KEY) || {}) {
+    const {
+      last = NULL_ADDRESS,
+      store = []
+    } = data;
+
+    this.persist = debounce(() => {
+      localStore.set(LS_STORE_KEY, this);
+    }, 100);
+
+    this._last = last;
+    this._store = store.map((data) => new Account(this.persist, data));
+  }
+
+  create (secret, password) {
+    const privateKey = Buffer.from(secret.slice(2), 'hex');
+    const account = Account.fromPrivateKey(this.persist, privateKey, password);
+
+    this._store.push(account);
+    this.lastAddress = account.address;
+
+    this.persist();
+
+    return account.address;
+  }
+
+  set lastAddress (value) {
+    this._last = value.toLowerCase();
+  }
+
+  get lastAddress () {
+    return this._last;
+  }
+
+  get (address) {
+    address = address.toLowerCase();
+
+    this.lastAddress = address;
+
+    const account = this._store.find((account) => account.address === address);
+
+    if (!account) {
+      throw new Error(`Account not found: ${address}`);
+    }
+
+    return account;
+  }
+
+  remove (address, password) {
+    address = address.toLowerCase();
+
+    const index = this._store.findIndex((account) => account.address === address);
+
+    if (index === -1) {
+      return false;
+    }
+
+    const account = this._store[index];
+
+    if (!account.isValidPassword(password)) {
+      console.log('invalid password');
+      return false;
+    }
+
+    if (address === this.lastAddress) {
+      this.lastAddress = NULL_ADDRESS;
+    }
+
+    this._store.splice(index, 1);
+
+    this.persist();
+
+    return true;
+  }
+
+  mapArray (mapper) {
+    return this._store.map(mapper);
+  }
+
+  mapObject (mapper) {
+    const result = {};
+
+    this._store.forEach((account) => {
+      result[account.address] = mapper(account);
+    });
+
+    return result;
+  }
+
+  toJSON () {
+    return {
+      last: this._last,
+      store: this._store
+    };
+  }
+}

js/src/api/local/accounts/index.js

@@ -0,0 +1,21 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import Accounts from './accounts';
+
+const accounts = new Accounts();
+
+export default accounts;

js/src/api/local/ethkey/index.js

@@ -0,0 +1,87 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import dictionary from './dictionary';
+
+// Allow a web worker in the browser, with a fallback for Node.js
+const hasWebWorkers = typeof Worker !== 'undefined';
+const KeyWorker = hasWebWorkers ? require('worker-loader!./worker')
+                                : require('./worker').KeyWorker;
+
+// Local accounts should never be used outside of the browser
+export let keythereum = null;
+
+if (hasWebWorkers) {
+  require('keythereum/dist/keythereum');
+
+  keythereum = window.keythereum;
+}
+
+export function phraseToAddress (phrase) {
+  return phraseToWallet(phrase).then((wallet) => wallet.address);
+}
+
+export function phraseToWallet (phrase) {
+  return new Promise((resolve, reject) => {
+    const worker = new KeyWorker();
+
+    worker.postMessage(phrase);
+    worker.onmessage = ({ data }) => {
+      resolve(data);
+    };
+  });
+}
+
+export function randomBytes (length) {
+  if (keythereum) {
+    return keythereum.crypto.randomBytes(length);
+  }
+
+  const buf = Buffer.alloc(length);
+
+  for (let i = 0; i < length; i++) {
+    buf[i] = Math.random() * 255;
+  }
+
+  return buf;
+}
+
+export function randomNumber (max) {
+  // Use 24 bits to avoid the integer becoming signed via bitshifts
+  const rand = randomBytes(3);
+
+  const integer = (rand[0] << 16) | (rand[1] << 8) | rand[2];
+
+  // floor to integer value via bitor 0
+  return ((integer / 0xFFFFFF) * max) | 0;
+}
+
+export function randomWord () {
+  // TODO mh: use better entropy
+  const index = randomNumber(dictionary.length);
+
+  return dictionary[index];
+}
+
+export function randomPhrase (length) {
+  const words = [];
+
+  while (length--) {
+    words.push(randomWord());
+  }
+
+  return words.join(' ');
+}

js/src/api/local/ethkey/index.spec.js

@@ -0,0 +1,95 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import dictionary from './dictionary';
+import {
+  phraseToAddress,
+  phraseToWallet,
+  randomNumber,
+  randomWord,
+  randomPhrase
+} from './';
+
+describe('api/local/ethkey', () => {
+  describe('randomNumber', () => {
+    it('generates numbers in range', () => {
+      for (let i = 0; i < 100; i++) {
+        const number = randomNumber(7777);
+
+        expect(number).to.be.at.least(0);
+        expect(number).to.be.below(7777);
+        expect(number % 1).to.be.equal(0);
+      }
+    });
+  });
+
+  describe('randomWord', () => {
+    it('generates a random word from the dictionary', () => {
+      const word = randomWord();
+
+      expect(dictionary.includes(word)).to.be.equal(true);
+    });
+  });
+
+  describe('randomPhrase', () => {
+    it('generates a random phrase from the dictionary', () => {
+      const phrase = randomPhrase(7).split(' ');
+
+      expect(phrase.length).to.be.equal(7);
+
+      phrase.forEach((word) => {
+        expect(dictionary.includes(word)).to.be.equal(true);
+      });
+    });
+  });
+
+  describe('phraseToAddress', function () {
+    this.timeout(10000);
+
+    it('generates a valid address', () => {
+      const phrase = randomPhrase(12);
+
+      return phraseToAddress(phrase).then((address) => {
+        expect(address.length).to.be.equal(42);
+        expect(address.slice(0, 4)).to.be.equal('0x00');
+      });
+    });
+
+    it('generates valid address for empty phrase', () => {
+      return phraseToAddress('').then((address) => {
+        expect(address).to.be.equal('0x00a329c0648769a73afac7f9381e08fb43dbea72');
+      });
+    });
+  });
+
+  describe('phraseToWallet', function () {
+    this.timeout(10000);
+
+    it('generates a valid wallet object', () => {
+      const phrase = randomPhrase(12);
+
+      return phraseToWallet(phrase).then((wallet) => {
+        expect(wallet.address.length).to.be.equal(42);
+        expect(wallet.secret.length).to.be.equal(66);
+        expect(wallet.public.length).to.be.equal(130);
+
+        expect(wallet.address.slice(0, 4)).to.be.equal('0x00');
+        expect(wallet.secret.slice(0, 2)).to.be.equal('0x');
+        expect(wallet.public.slice(0, 2)).to.be.equal('0x');
+      });
+    });
+  });
+});

js/src/api/local/ethkey/worker.js

@@ -0,0 +1,89 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import { keccak_256 as keccak256 } from 'js-sha3';
+import secp256k1 from 'secp256k1/js';
+
+// Stay compatible between environments
+if (typeof self !== 'object') {
+  const scope = typeof global === 'undefined' ? window : global;
+
+  scope.self = scope;
+}
+
+function bytesToHex (bytes) {
+  return '0x' + Array.from(bytes).map(n => ('0' + n.toString(16)).slice(-2)).join('');
+}
+
+// Logic ported from /ethkey/src/brain.rs
+function phraseToWallet (phrase) {
+  let secret = keccak256.array(phrase);
+
+  for (let i = 0; i < 16384; i++) {
+    secret = keccak256.array(secret);
+  }
+
+  while (true) {
+    secret = keccak256.array(secret);
+
+    const secretBuf = Buffer.from(secret);
+
+    if (secp256k1.privateKeyVerify(secretBuf)) {
+      // No compression, slice out last 64 bytes
+      const publicBuf = secp256k1.publicKeyCreate(secretBuf, false).slice(-64);
+      const address = keccak256.array(publicBuf).slice(12);
+
+      if (address[0] !== 0) {
+        continue;
+      }
+
+      const wallet = {
+        secret: bytesToHex(secretBuf),
+        public: bytesToHex(publicBuf),
+        address: bytesToHex(address)
+      };
+
+      return wallet;
+    }
+  }
+}
+
+self.onmessage = function ({ data }) {
+  const wallet = phraseToWallet(data);
+
+  postMessage(wallet);
+  close();
+};
+
+// Emulate a web worker in Node.js
+class KeyWorker {
+  postMessage (data) {
+    // Force async
+    setTimeout(() => {
+      const wallet = phraseToWallet(data);
+
+      this.onmessage({ data: wallet });
+    }, 0);
+  }
+
+  onmessage (event) {
+    // no-op to be overriden
+  }
+}
+
+if (exports != null) {
+  exports.KeyWorker = KeyWorker;
+}

js/src/api/local/index.js

@@ -0,0 +1,17 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+export LocalAccountsMiddleware from './middleware';

js/src/api/local/middleware.js

@@ -0,0 +1,173 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import EthereumTx from 'ethereumjs-tx';
+import accounts from './accounts';
+import transactions from './transactions';
+import { Middleware } from '../transport';
+import { inNumber16 } from '../format/input';
+import { phraseToWallet, phraseToAddress, randomPhrase } from './ethkey';
+
+export default class LocalAccountsMiddleware extends Middleware {
+  // Maps transaction requests to transaction hashes.
+  // This allows the locally-signed transactions to emulate the signer.
+  transactionHashes = {};
+  transactions = {};
+
+  // Current transaction id. This doesn't need to be stored, as it's
+  // only relevant for the current the session.
+  transactionId = 1;
+
+  constructor (transport) {
+    super(transport);
+
+    const register = this.register.bind(this);
+
+    register('eth_accounts', () => {
+      return accounts.mapArray((account) => account.address);
+    });
+
+    register('eth_coinbase', () => {
+      return accounts.lastAddress;
+    });
+
+    register('parity_accountsInfo', () => {
+      return accounts.mapObject(({ name }) => {
+        return { name };
+      });
+    });
+
+    register('parity_allAccountsInfo', () => {
+      return accounts.mapObject(({ name, meta, uuid }) => {
+        return { name, meta, uuid };
+      });
+    });
+
+    register('parity_checkRequest', ([id]) => {
+      return transactions.hash(id) || Promise.resolve(null);
+    });
+
+    register('parity_defaultAccount', () => {
+      return accounts.lastAddress;
+    });
+
+    register('parity_generateSecretPhrase', () => {
+      return randomPhrase(12);
+    });
+
+    register('parity_getNewDappsAddresses', () => {
+      return [];
+    });
+
+    register('parity_hardwareAccountsInfo', () => {
+      return {};
+    });
+
+    register('parity_newAccountFromPhrase', ([phrase, password]) => {
+      return phraseToWallet(phrase)
+        .then((wallet) => {
+          return accounts.create(wallet.secret, password);
+        });
+    });
+
+    register('parity_setAccountMeta', ([address, meta]) => {
+      accounts.get(address).meta = meta;
+
+      return true;
+    });
+
+    register('parity_setAccountName', ([address, name]) => {
+      accounts.get(address).name = name;
+
+      return true;
+    });
+
+    register('parity_postTransaction', ([tx]) => {
+      if (!tx.from) {
+        tx.from = accounts.lastAddress;
+      }
+
+      tx.nonce = null;
+      tx.condition = null;
+
+      return transactions.add(tx);
+    });
+
+    register('parity_phraseToAddress', ([phrase]) => {
+      return phraseToAddress(phrase);
+    });
+
+    register('parity_useLocalAccounts', () => {
+      return true;
+    });
+
+    register('parity_listGethAccounts', () => {
+      return [];
+    });
+
+    register('parity_listRecentDapps', () => {
+      return {};
+    });
+
+    register('parity_killAccount', ([address, password]) => {
+      return accounts.remove(address, password);
+    });
+
+    register('signer_confirmRequest', ([id, modify, password]) => {
+      const {
+        gasPrice,
+        gas: gasLimit,
+        from,
+        to,
+        value,
+        data
+      } = Object.assign(transactions.get(id), modify);
+
+      return this
+        .rpcRequest('parity_nextNonce', [from])
+        .then((nonce) => {
+          const tx = new EthereumTx({
+            nonce,
+            to,
+            data,
+            gasLimit: inNumber16(gasLimit),
+            gasPrice: inNumber16(gasPrice),
+            value: inNumber16(value)
+          });
+          const account = accounts.get(from);
+
+          tx.sign(account.decryptPrivateKey(password));
+
+          const serializedTx = `0x${tx.serialize().toString('hex')}`;
+
+          return this.rpcRequest('eth_sendRawTransaction', [serializedTx]);
+        })
+        .then((hash) => {
+          transactions.confirm(id, hash);
+
+          return {};
+        });
+    });
+
+    register('signer_rejectRequest', ([id]) => {
+      return transactions.reject(id);
+    });
+
+    register('signer_requestsToConfirm', () => {
+      return transactions.requestsToConfirm();
+    });
+  }
+}

js/src/api/local/transactions.js

@@ -0,0 +1,123 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import { toHex } from '../util/format';
+import { TransportError } from '../transport';
+
+const AWAITING = Symbol('awaiting');
+const CONFIRMED = Symbol('confirmed');
+const REJECTED = Symbol('rejected');
+
+class Transactions {
+  constructor () {
+    this.reset();
+  }
+
+  // should only really be needed in the constructor and tests
+  reset () {
+    this._id = 1;
+    this._states = {};
+  }
+
+  nextId () {
+    return toHex(this._id++);
+  }
+
+  add (tx) {
+    const id = this.nextId();
+
+    this._states[id] = {
+      status: AWAITING,
+      transaction: tx
+    };
+
+    return id;
+  }
+
+  get (id) {
+    const state = this._states[id];
+
+    if (!state || state.status !== AWAITING) {
+      return null;
+    }
+
+    return state.transaction;
+  }
+
+  hash (id) {
+    const state = this._states[id];
+
+    if (!state) {
+      return null;
+    }
+
+    switch (state.status) {
+      case REJECTED:
+        throw TransportError.requestRejected();
+      case CONFIRMED:
+        return state.hash;
+      default:
+        return null;
+    }
+  }
+
+  confirm (id, hash) {
+    const state = this._states[id];
+
+    if (!state || state.status !== AWAITING) {
+      throw new Error('Trying to confirm an invalid transaction');
+    }
+
+    state.hash = hash;
+    state.status = CONFIRMED;
+  }
+
+  reject (id) {
+    const state = this._states[id];
+
+    if (!state) {
+      return false;
+    }
+
+    state.status = REJECTED;
+
+    return true;
+  }
+
+  requestsToConfirm () {
+    const result = [];
+
+    Object.keys(this._states).forEach((id) => {
+      const state = this._states[id];
+
+      if (state.status === AWAITING) {
+        result.push({
+          id,
+          origin: {
+            signer: '0x0'
+          },
+          payload: {
+            sendTransaction: state.transaction
+          }
+        });
+      }
+    });
+
+    return result;
+  }
+}
+
+export default new Transactions();

js/src/api/local/transactions.spec.js

@@ -0,0 +1,68 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import transactions from './transactions';
+import { TransportError } from '../transport/error';
+
+const DUMMY_TX = 'dummy';
+
+describe('api/local/transactions', () => {
+  beforeEach(() => {
+    transactions.reset();
+  });
+
+  it('can store transactions', () => {
+    const id1 = transactions.add(DUMMY_TX);
+    const id2 = transactions.add(DUMMY_TX);
+    const requests = transactions.requestsToConfirm();
+
+    expect(id1).to.be.equal('0x1');
+    expect(id2).to.be.equal('0x2');
+    expect(requests.length).to.be.equal(2);
+    expect(requests[0].id).to.be.equal(id1);
+    expect(requests[1].id).to.be.equal(id2);
+    expect(requests[0].payload.sendTransaction).to.be.equal(DUMMY_TX);
+    expect(requests[1].payload.sendTransaction).to.be.equal(DUMMY_TX);
+  });
+
+  it('can confirm transactions', () => {
+    const id1 = transactions.add(DUMMY_TX);
+    const id2 = transactions.add(DUMMY_TX);
+
+    const hash1 = '0x1111111111111111111111111111111111111111';
+    const hash2 = '0x2222222222222222222222222222222222222222';
+
+    transactions.confirm(id1, hash1);
+    transactions.confirm(id2, hash2);
+
+    const requests = transactions.requestsToConfirm();
+
+    expect(requests.length).to.be.equal(0);
+    expect(transactions.hash(id1)).to.be.equal(hash1);
+    expect(transactions.hash(id2)).to.be.equal(hash2);
+  });
+
+  it('can reject transactions', () => {
+    const id = transactions.add(DUMMY_TX);
+
+    transactions.reject(id);
+
+    const requests = transactions.requestsToConfirm();
+
+    expect(requests.length).to.be.equal(0);
+    expect(() => transactions.hash(id)).to.throw(TransportError);
+  });
+});

js/src/api/transport/error.js

@@ -42,6 +42,10 @@ export const ERROR_CODES = {
 };
 
 export default class TransportError extends ExtendableError {
+  static requestRejected (method = null) {
+    return new TransportError(method, ERROR_CODES.REQUEST_REJECTED, 'Request has been rejected.');
+  }
+
   constructor (method, code, message) {
     const m = `${method}: ${code}: ${message}`;
 

js/src/api/transport/http/http.js

@@ -46,7 +46,7 @@ export default class Http extends JsonRpcBase {
     };
   }
 
-  execute (method, ...params) {
+  _execute (method, params) {
     const request = this._encodeOptions(method, params);
 
     return fetch(this._url, request)

js/src/api/transport/index.js

@@ -16,4 +16,5 @@
 
 export Http from './http';
 export Ws from './ws';
-export TransportError from './error.js';
+export TransportError from './error';
+export Middleware from './middleware';

js/src/api/transport/jsonRpcBase.js

@@ -15,6 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 import EventEmitter from 'eventemitter3';
+import { Logging } from '../subscriptions';
 
 export default class JsonRpcBase extends EventEmitter {
   constructor () {
@@ -23,6 +24,7 @@ export default class JsonRpcBase extends EventEmitter {
     this._id = 1;
     this._debug = false;
     this._connected = false;
+    this._middlewareList = Promise.resolve([]);
   }
 
   encode (method, params) {
@@ -36,6 +38,65 @@ export default class JsonRpcBase extends EventEmitter {
     return json;
   }
 
+  addMiddleware (middleware) {
+    this._middlewareList = Promise
+      .all([
+        middleware,
+        this._middlewareList
+      ])
+      .then(([middleware, middlewareList]) => {
+        // Do nothing if `handlerPromise` resolves to a null-y value.
+        if (middleware == null) {
+          return middlewareList;
+        }
+
+        // don't mutate the original array
+        return middlewareList.concat([middleware]);
+      });
+  }
+
+  _wrapSuccessResult (result) {
+    return {
+      id: this._id,
+      jsonrpc: '2.0',
+      result
+    };
+  }
+
+  _wrapErrorResult (error) {
+    return {
+      id: this._id,
+      jsonrpc: '2.0',
+      error: {
+        code: error.code,
+        message: error.text
+      }
+    };
+  }
+
+  execute (method, ...params) {
+    return this._middlewareList.then((middlewareList) => {
+      for (const middleware of middlewareList) {
+        const res = middleware.handle(method, params);
+
+        if (res != null) {
+          const result = this._wrapSuccessResult(res);
+          const json = this.encode(method, params);
+
+          Logging.send(method, params, { json, result });
+
+          return res;
+        }
+      }
+
+      return this._execute(method, params);
+    });
+  }
+
+  _execute () {
+    throw new Error('Missing implementation of JsonRpcBase#_execute');
+  }
+
   _setConnected () {
     if (!this._connected) {
       this._connected = true;

js/src/api/transport/middleware.js

@@ -0,0 +1,42 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+export default class Middleware {
+  constructor (transport) {
+    this._transport = transport;
+    this._handlers = {};
+  }
+
+  register (method, handler) {
+    this._handlers[method] = handler;
+  }
+
+  handle (method, params) {
+    const handler = this._handlers[method];
+
+    if (handler != null) {
+      const response = handler(params);
+
+      return response;
+    }
+
+    return null;
+  }
+
+  rpcRequest (method, params) {
+    return this._transport._execute(method, params);
+  }
+}

js/src/api/transport/middleware.spec.js

@@ -0,0 +1,58 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import Middleware from './middleware';
+import JsonRpcBase from './jsonRpcBase';
+
+const MOCKED = 'mocked!';
+
+class MockTransport extends JsonRpcBase {
+  _execute () {
+    return Promise.resolve(MOCKED);
+  }
+}
+
+describe('api/transport/Middleware', () => {
+  let middleware;
+  let transport;
+
+  beforeEach(() => {
+    transport = new MockTransport();
+    middleware = new Middleware(transport);
+
+    middleware.register('mock_rpc', ([num]) => num);
+    middleware.register('mock_null', () => null);
+    transport.addMiddleware(middleware);
+  });
+
+  it('Routes requests to middleware', () => {
+    return transport.execute('mock_rpc', 100).then((num) => {
+      expect(num).to.be.equal(100);
+    });
+  });
+
+  it('Passes non-mocked requests through', () => {
+    return transport.execute('not_moced', 200).then((result) => {
+      expect(result).to.be.equal(MOCKED);
+    });
+  });
+
+  it('Passes mocked requests through, if middleware returns null', () => {
+    return transport.execute('mock_null', 300).then((result) => {
+      expect(result).to.be.equal(MOCKED);
+    });
+  });
+});

js/src/api/transport/ws/ws.js

@@ -244,7 +244,7 @@ export default class Ws extends JsonRpcBase {
     message.timestamp = Date.now();
   }
 
-  execute (method, ...params) {
+  _execute (method, params) {
     return new Promise((resolve, reject) => {
       const id = this.id;
       const json = this.encode(method, params);