const Streams = require('mississippi') const ObjectMultiplex = require('./obj-multiplex') const StreamProvider = require('web3-stream-provider') const RemoteStore = require('./remote-store.js').RemoteStore module.exports = MetamaskInpageProvider function MetamaskInpageProvider (connectionStream) { const self = this // setup connectionStream multiplexing var multiStream = ObjectMultiplex() Streams.pipe(connectionStream, multiStream, connectionStream, function (err) { console.warn('MetamaskInpageProvider - lost connection to MetaMask') if (err) throw err }) self.multiStream = multiStream // subscribe to metamask public config var publicConfigStore = remoteStoreWithLocalStorageCache('MetaMask-Config') var storeStream = publicConfigStore.createStream() Streams.pipe(storeStream, multiStream.createStream('publicConfig'), storeStream, function (err) { console.warn('MetamaskInpageProvider - lost connection to MetaMask publicConfig') if (err) throw err }) self.publicConfigStore = publicConfigStore // connect to async provider var asyncProvider = new StreamProvider() Streams.pipe(asyncProvider, multiStream.createStream('provider'), asyncProvider, function (err) { console.warn('MetamaskInpageProvider - lost connection to MetaMask provider') if (err) throw err }) asyncProvider.on('error', console.error.bind(console)) self.asyncProvider = asyncProvider self.idMap = {} // handle sendAsync requests via asyncProvider self.sendAsync = function(payload, cb){ // rewrite request ids var request = eachJsonMessage(payload, (message) => { var newId = createRandomId() self.idMap[newId] = message.id message.id = newId return message }) // forward to asyncProvider asyncProvider.sendAsync(request, function(err, res){ if (err) return cb(err) // transform messages to original ids eachJsonMessage(res, (message) => { var oldId = self.idMap[message.id] delete self.idMap[message.id] message.id = oldId return message }) cb(null, res) }) } } MetamaskInpageProvider.prototype.send = function (payload) { const self = this let selectedAddress let result = null switch (payload.method) { case 'eth_accounts': // read from localStorage selectedAddress = self.publicConfigStore.get('selectedAddress') result = selectedAddress ? [selectedAddress] : [] break case 'eth_coinbase': // read from localStorage selectedAddress = self.publicConfigStore.get('selectedAddress') result = selectedAddress || '0x0000000000000000000000000000000000000000' break // throw not-supported Error default: var message = 'The MetaMask Web3 object does not support synchronous methods like ' + payload.method + '. See https://github.com/MetaMask/faq/blob/master/DEVELOPERS.md#all-async---think-of-metamask-as-a-light-client for details.' throw new Error(message) } // return the result return { id: payload.id, jsonrpc: payload.jsonrpc, result: result, } } MetamaskInpageProvider.prototype.sendAsync = function () { throw new Error('MetamaskInpageProvider - sendAsync not overwritten') } MetamaskInpageProvider.prototype.isConnected = function () { return true } // util function remoteStoreWithLocalStorageCache (storageKey) { // read local cache var initState = JSON.parse(localStorage[storageKey] || '{}') var store = new RemoteStore(initState) // cache the latest state locally store.subscribe(function (state) { localStorage[storageKey] = JSON.stringify(state) }) return store } function createRandomId(){ const extraDigits = 3 // 13 time digits const datePart = new Date().getTime() * Math.pow(10, extraDigits) // 3 random digits const extraPart = Math.floor(Math.random() * Math.pow(10, extraDigits)) // 16 digits return datePart + extraPart } function eachJsonMessage(payload, transformFn){ if (Array.isArray(payload)) { return payload.map(transformFn) } else { return transformFn(payload) } }