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const pipe = require('pump')
const StreamSubprovider = require('web3-stream-provider/stream-subprovider')
const ProviderEngine = require('web3-provider-engine')
const LocalStorageStore = require('obs-store')
const ObjectMultiplex = require('./obj-multiplex')
const createRandomId = require('./random-id')
module.exports = MetamaskInpageProvider
function MetamaskInpageProvider (connectionStream) {
const self = this
// setup connectionStream multiplexing
var multiStream = self.multiStream = ObjectMultiplex()
pipe(
connectionStream,
multiStream,
connectionStream,
(err) => logStreamDisconnectWarning('MetaMask', err)
)
// subscribe to metamask public config (one-way)
self.publicConfigStore = new LocalStorageStore({ storageKey: 'MetaMask-Config' })
pipe(
multiStream.createStream('publicConfig'),
self.publicConfigStore,
(err) => logStreamDisconnectWarning('MetaMask PublicConfigStore', err)
)
// connect to async provider
const engine = self.asyncProvider = new ProviderEngine()
const stream = self.stream = new StreamSubprovider()
engine.addProvider(stream)
pipe(
stream,
multiStream.createStream('provider'),
stream,
(err) => logStreamDisconnectWarning('MetaMask RpcProvider', err)
)
// start polling
engine.start()
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
console.log('sending async to engine', request)
engine.sendAsync(request, function (err, res) {
console.log('send async returned !!', 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.getState().selectedAddress
result = selectedAddress ? [selectedAddress] : []
break
case 'eth_coinbase':
// read from localStorage
selectedAddress = self.publicConfigStore.getState().selectedAddress
result = selectedAddress
break
case 'eth_uninstallFilter':
self.sendAsync(payload, noop)
result = true
break
case 'net_version':
const networkVersion = self.publicConfigStore.getState().networkVersion
result = networkVersion
break
// throw not-supported Error
default:
var link = 'https://github.com/MetaMask/faq/blob/master/DEVELOPERS.md#dizzy-all-async---think-of-metamask-as-a-light-client'
var message = `The MetaMask Web3 object does not support synchronous methods like ${payload.method} without a callback parameter. See ${link} 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
}
MetamaskInpageProvider.prototype.isMetaMask = true
// util
function eachJsonMessage (payload, transformFn) {
if (Array.isArray(payload)) {
return payload.map(transformFn)
} else {
return transformFn(payload)
}
}
function logStreamDisconnectWarning (remoteLabel, err) {
let warningMsg = `MetamaskInpageProvider - lost connection to ${remoteLabel}`
if (err) warningMsg += '\n' + err.stack
console.warn(warningMsg)
}
function noop () {}
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