contentscript.js - Documentation

const fs = require('fs')
-const path = require('path')
-const pump = require('pump')
-const LocalMessageDuplexStream = require('post-message-stream')
-const PongStream = require('ping-pong-stream/pong')
-const ObjectMultiplex = require('obj-multiplex')
-const extension = require('extensionizer')
-const PortStream = require('./lib/port-stream.js')
-
-const inpageContent = fs.readFileSync(path.join(__dirname, '..', '..', 'dist', 'chrome', 'inpage.js')).toString()
-const inpageSuffix = '//# sourceURL=' + extension.extension.getURL('inpage.js') + '\n'
-const inpageBundle = inpageContent + inpageSuffix
-
-// Eventually this streaming injection could be replaced with:
-// https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Language_Bindings/Components.utils.exportFunction
-//
-// But for now that is only Firefox
-// If we create a FireFox-only code path using that API,
-// MetaMask will be much faster loading and performant on Firefox.
-
-if (shouldInjectWeb3()) {
-  setupInjection()
-  setupStreams()
-}
-
-/**
- * Creates a script tag that injects inpage.js
- */
-function setupInjection () {
-  try {
-    // inject in-page script
-    var scriptTag = document.createElement('script')
-    scriptTag.textContent = inpageBundle
-    scriptTag.onload = function () { this.parentNode.removeChild(this) }
-    var container = document.head || document.documentElement
-    // append as first child
-    container.insertBefore(scriptTag, container.children[0])
-  } catch (e) {
-    console.error('Metamask injection failed.', e)
-  }
-}
-
-/**
- * Sets up two-way communication streams between the
- * browser extension and local per-page browser context
- */
-function setupStreams () {
-  // setup communication to page and plugin
-  const pageStream = new LocalMessageDuplexStream({
-    name: 'contentscript',
-    target: 'inpage',
-  })
-  const pluginPort = extension.runtime.connect({ name: 'contentscript' })
-  const pluginStream = new PortStream(pluginPort)
-
-  // forward communication plugin->inpage
-  pump(
-    pageStream,
-    pluginStream,
-    pageStream,
-    (err) => logStreamDisconnectWarning('MetaMask Contentscript Forwarding', err)
-  )
-
-  // setup local multistream channels
-  const mux = new ObjectMultiplex()
-  mux.setMaxListeners(25)
-
-  pump(
-    mux,
-    pageStream,
-    mux,
-    (err) => logStreamDisconnectWarning('MetaMask Inpage', err)
-  )
-  pump(
-    mux,
-    pluginStream,
-    mux,
-    (err) => logStreamDisconnectWarning('MetaMask Background', err)
-  )
-
-  // connect ping stream
-  const pongStream = new PongStream({ objectMode: true })
-  pump(
-    mux,
-    pongStream,
-    mux,
-    (err) => logStreamDisconnectWarning('MetaMask PingPongStream', err)
-  )
-
-  // connect phishing warning stream
-  const phishingStream = mux.createStream('phishing')
-  phishingStream.once('data', redirectToPhishingWarning)
-
-  // ignore unused channels (handled by background, inpage)
-  mux.ignoreStream('provider')
-  mux.ignoreStream('publicConfig')
-}
-
-
-/**
- * Error handler for page to plugin stream disconnections
- *
- * @param {string} remoteLabel Remote stream name
- * @param {Error} err Stream connection error
- */
-function logStreamDisconnectWarning (remoteLabel, err) {
-  let warningMsg = `MetamaskContentscript - lost connection to ${remoteLabel}`
-  if (err) warningMsg += '\n' + err.stack
-  console.warn(warningMsg)
-}
-
-/**
- * Determines if Web3 should be injected
- *
- * @returns {boolean} True of Web3 should be injected
- */
-function shouldInjectWeb3 () {
-  return doctypeCheck() && suffixCheck()
-    && documentElementCheck() && !blacklistedDomainCheck()
-}
-
-/**
- * Checks the doctype of the current document if it exists
- *
- * @returns {boolean} True if the doctype is html or if none exists
- */
-function doctypeCheck () {
-  const doctype = window.document.doctype
-  if (doctype) {
-    return doctype.name === 'html'
-  } else {
-    return true
-  }
-}
-
-/**
- * Checks the current document extension
- *
- * @returns {boolean} True if the current extension is not prohibited
- */
-function suffixCheck () {
-  var prohibitedTypes = ['xml', 'pdf']
-  var currentUrl = window.location.href
-  var currentRegex
-  for (let i = 0; i < prohibitedTypes.length; i++) {
-    currentRegex = new RegExp(`\\.${prohibitedTypes[i]}$`)
-    if (currentRegex.test(currentUrl)) {
-      return false
-    }
-  }
-  return true
-}
-
-/**
- * Checks the documentElement of the current document
- *
- * @returns {boolean} True if the documentElement is an html node or if none exists
- */
-function documentElementCheck () {
-  var documentElement = document.documentElement.nodeName
-  if (documentElement) {
-    return documentElement.toLowerCase() === 'html'
-  }
-  return true
-}
-
-/**
- * Checks if the current domain is blacklisted
- * 
- * @returns {boolean} True if the current domain is blacklisted
- */
-function blacklistedDomainCheck () {
-  var blacklistedDomains = [
-    'uscourts.gov',
-    'dropbox.com',
-    'webbyawards.com',
-  ]
-  var currentUrl = window.location.href
-  var currentRegex
-  for (let i = 0; i < blacklistedDomains.length; i++) {
-    const blacklistedDomain = blacklistedDomains[i].replace('.', '\\.')
-    currentRegex = new RegExp(`(?:https?:\\/\\/)(?:(?!${blacklistedDomain}).)*$`)
-    if (!currentRegex.test(currentUrl)) {
-      return true
-    }
-  }
-  return false
-}
-
-/**
- * Redirects the current page to a phishing information page
- */
-function redirectToPhishingWarning () {
-  console.log('MetaMask - redirecting to phishing warning')
-  window.location.href = 'https://metamask.io/phishing.html'
-}
-