const EventEmitter = require('events') const MetaMaskProvider = require('web3-provider-engine/zero.js') const ObservableStore = require('obs-store') const ComposedStore = require('obs-store/lib/composed') const extend = require('xtend') const EthQuery = require('eth-query') const RPC_ADDRESS_LIST = require('../config.js').network const DEFAULT_RPC = RPC_ADDRESS_LIST['rinkeby'] module.exports = class NetworkController extends EventEmitter { constructor (config) { super() this.networkStore = new ObservableStore('loading') config.provider.rpcTarget = this.getRpcAddressForType(config.provider.type, config.provider) this.providerStore = new ObservableStore(config.provider) this.store = new ComposedStore({ provider: this.providerStore, network: this.networkStore }) this._providerListeners = {} this.on('networkDidChange', this.lookupNetwork) this.providerStore.subscribe((state) => this.switchNetwork({rpcUrl: state.rpcTarget})) } get provider () { return this._proxy } set provider (provider) { this._provider = provider } initializeProvider (opts) { this.providerInit = opts this._provider = MetaMaskProvider(opts) this._proxy = new Proxy(this._provider, { get: (obj, name) => { if (name === 'on') return this._on.bind(this) return this._provider[name] }, set: (obj, name, value) => { this._provider[name] = value }, }) this.provider.on('block', this._logBlock.bind(this)) this.provider.on('error', this.verifyNetwork.bind(this)) this.ethQuery = new EthQuery(this.provider) this.lookupNetwork() return this.provider } switchNetwork (providerInit) { this.setNetworkState('loading') const newInit = extend(this.providerInit, providerInit) this.providerInit = newInit this._provider.removeAllListeners() this._provider.stop() this.provider = MetaMaskProvider(newInit) // apply the listners created by other controllers Object.keys(this._providerListeners).forEach((key) => { this._providerListeners[key].forEach((handler) => this._provider.addListener(key, handler)) }) this.emit('networkDidChange') } verifyNetwork () { // Check network when restoring connectivity: if (this.isNetworkLoading()) this.lookupNetwork() } getNetworkState () { return this.networkStore.getState() } setNetworkState (network) { return this.networkStore.putState(network) } isNetworkLoading () { return this.getNetworkState() === 'loading' } lookupNetwork () { this.ethQuery.sendAsync({ method: 'net_version' }, (err, network) => { if (err) return this.setNetworkState('loading') log.info('web3.getNetwork returned ' + network) this.setNetworkState(network) }) } setRpcTarget (rpcUrl) { this.providerStore.updateState({ type: 'rpc', rpcTarget: rpcUrl, }) } getCurrentRpcAddress () { const provider = this.getProviderConfig() if (!provider) return null return this.getRpcAddressForType(provider.type) } setProviderType (type) { if (type === this.getProviderConfig().type) return const rpcTarget = this.getRpcAddressForType(type) this.providerStore.updateState({type, rpcTarget}) } getProviderConfig () { return this.providerStore.getState() } getRpcAddressForType (type, provider = this.getProviderConfig()) { if (RPC_ADDRESS_LIST[type]) return RPC_ADDRESS_LIST[type] return provider && provider.rpcTarget ? provider.rpcTarget : DEFAULT_RPC } _logBlock (block) { 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) } }