Merge pull request #2180 from MetaMask/proxy-blockTracker

Wrap block tracker in events proxy

app/scripts/controllers/network.js

@@ -4,6 +4,7 @@ const ObservableStore = require('obs-store')
 const ComposedStore = require('obs-store/lib/composed')
 const extend = require('xtend')
 const EthQuery = require('eth-query')
+const createEventEmitterProxy = require('../lib/events-proxy.js')
 const RPC_ADDRESS_LIST = require('../config.js').network
 const DEFAULT_RPC = RPC_ADDRESS_LIST['rinkeby']
 
@@ -31,16 +32,8 @@ module.exports = class NetworkController extends EventEmitter {
   initializeProvider (opts, providerContructor = MetaMaskProvider) {
     this.providerInit = opts
     this._provider = providerContructor(opts)
-    this._proxy = new Proxy(this._provider, {
+    this._proxy = createEventEmitterProxy(this._provider)
-      get: (obj, name) => {
+    this.provider._blockTracker = createEventEmitterProxy(this._provider._blockTracker)
-        if (name === 'on') return this._on.bind(this)
-        return this._provider[name]
-      },
-      set: (obj, name, value) => {
-        this._provider[name] = value
-        return value
-      },
-    })
     this.provider.on('block', this._logBlock.bind(this))
     this.provider.on('error', this.verifyNetwork.bind(this))
     this.ethQuery = new EthQuery(this.provider)
@@ -55,11 +48,11 @@ module.exports = class NetworkController extends EventEmitter {
 
     this._provider.removeAllListeners()
     this._provider.stop()
-    this.provider = MetaMaskProvider(newInit)
+    this._provider = MetaMaskProvider(newInit)
     // apply the listners created by other controllers
-    Object.keys(this._providerListeners).forEach((key) => {
+    const blockTrackerHandlers = this.provider._blockTracker.proxyEventHandlers
-      this._providerListeners[key].forEach((handler) => this._provider.addListener(key, handler))
+    this.provider.setTarget(this._provider)
-    })
+    this.provider._blockTracker = createEventEmitterProxy(this._provider._blockTracker, blockTrackerHandlers)
     this.emit('networkDidChange')
   }
 
@@ -121,10 +114,4 @@ module.exports = class NetworkController extends EventEmitter {
     log.info(`BLOCK CHANGED: #${block.number.toString('hex')} 0x${block.hash.toString('hex')}`)
     this.verifyNetwork()
   }
-
-  _on (event, handler) {
-    if (!this._providerListeners[event]) this._providerListeners[event] = []
-    this._providerListeners[event].push(handler)
-    this._provider.on(event, handler)
-  }
 }

app/scripts/controllers/transactions.js

@@ -70,7 +70,7 @@ module.exports = class TransactionController extends EventEmitter {
     this.pendingTxTracker.on('txFailed', this.setTxStatusFailed.bind(this))
     this.pendingTxTracker.on('txConfirmed', this.setTxStatusConfirmed.bind(this))
 
-    this.blockTracker.on('rawBlock', this.pendingTxTracker.checkForTxInBlock.bind(this.pendingTxTracker))
+    this.blockTracker.on('block', this.pendingTxTracker.checkForTxInBlock.bind(this.pendingTxTracker))
     // this is a little messy but until ethstore has been either
     // removed or redone this is to guard against the race condition
     // where ethStore hasent been populated by the results yet

app/scripts/lib/events-proxy.js

@@ -0,0 +1,31 @@
+module.exports = function createEventEmitterProxy(eventEmitter, listeners) {
+  let target = eventEmitter
+  const eventHandlers = listeners || {}
+  const proxy = new Proxy({}, {
+    get: (obj, name) => {
+      // intercept listeners
+      if (name === 'on') return addListener
+      if (name === 'setTarget') return setTarget
+      if (name === 'proxyEventHandlers') return eventHandlers
+      return target[name]
+    },
+    set: (obj, name, value) => {
+      target[name] = value
+      return true
+    },
+  })
+  function setTarget (eventEmitter) {
+    target = eventEmitter
+    // migrate listeners
+    Object.keys(eventHandlers).forEach((name) => {
+      eventHandlers[name].forEach((handler) => target.on(name, handler))
+    })
+  }
+  function addListener (name, handler) {
+    if (!eventHandlers[name]) eventHandlers[name] = []
+    eventHandlers[name].push(handler)
+    target.on(name, handler)
+  }
+  if (listeners) proxy.setTarget(eventEmitter)
+  return proxy
+}

test/unit/network-contoller-test.js

@@ -21,7 +21,7 @@ describe('# Network Controller', function () {
       it('provider should be updatable without reassignment', function () {
         networkController.initializeProvider(networkControllerProviderInit, dummyProviderConstructor)
         const provider = networkController.provider
-        networkController._provider = {test: true}
+        networkController.provider.setTarget({test: true, on: () => {}})
         assert.ok(provider.test)
       })
     })
@@ -71,6 +71,7 @@ function dummyProviderConstructor() {
     // provider
     sendAsync: noop,
     // block tracker
+    _blockTracker: {},
     start: noop,
     stop: noop,
     on: noop,