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mirror of https://github.com/kremalicious/metamask-extension.git synced 2024-11-30 16:18:07 +01:00
metamask-extension/app/scripts/contentscript.js

75 lines
2.3 KiB
JavaScript

const LocalMessageDuplexStream = require('post-message-stream')
const PongStream = require('ping-pong-stream/pong')
const PortStream = require('./lib/port-stream.js')
const ObjectMultiplex = require('./lib/obj-multiplex')
const extension = require('./lib/extension')
const fs = require('fs')
const path = require('path')
const inpageText = fs.readFileSync(path.join(__dirname + '/inpage.js')).toString()
// 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()
}
function setupInjection(){
try {
// inject in-page script
var scriptTag = document.createElement('script')
scriptTag.src = extension.extension.getURL('scripts/inpage.js')
scriptTag.textContent = inpageText
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)
}
}
function setupStreams(){
// setup communication to page and plugin
var pageStream = new LocalMessageDuplexStream({
name: 'contentscript',
target: 'inpage',
})
pageStream.on('error', console.error)
var pluginPort = extension.runtime.connect({name: 'contentscript'})
var pluginStream = new PortStream(pluginPort)
pluginStream.on('error', console.error)
// forward communication plugin->inpage
pageStream.pipe(pluginStream).pipe(pageStream)
// setup local multistream channels
var mx = ObjectMultiplex()
mx.on('error', console.error)
mx.pipe(pageStream).pipe(mx)
// connect ping stream
var pongStream = new PongStream({ objectMode: true })
pongStream.pipe(mx.createStream('pingpong')).pipe(pongStream)
// ignore unused channels (handled by background)
mx.ignoreStream('provider')
mx.ignoreStream('publicConfig')
mx.ignoreStream('reload')
}
function shouldInjectWeb3(){
var shouldInject = (window.location.href.indexOf('.pdf') === -1)
return shouldInject
}