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mirror of https://github.com/kremalicious/metamask-extension.git synced 2024-12-23 01:39:44 +01:00

Inject inpage script synchronously

Huge thanks to the Firefox team, for their help on the issue of our long-standing inpage script race condition.

http://stackoverflow.com/questions/38577656/how-can-i-make-a-firefox-add-on-contentscript-inject-and-run-a-script-before-oth

The problem is that we were injecting a `script` tag and assigning its `src` attribute, which triggers an asynchronous fetch request, and does not guarantee execution order! (That was news to me!)

Instead, I'm now assigning the `script` tag a `textContent` value of the script to inject, and it seems to fix the problem!

There is also a Firefox-only API that could solve this whole problem in an even more elegant way, so we might want to expose a code path for that solution later on:

https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Language_Bindings/Components.utils.exportFunction

Allows you to expose an object from one scope to another. There was even talk of creating a polyfill for it that does virtually what we do, message passing between contexts.
This commit is contained in:
Dan Finlay 2016-07-25 16:34:29 -07:00
parent 6fa1d6efff
commit 913a9e85bd
3 changed files with 15 additions and 1 deletions

View File

@ -3,6 +3,17 @@ 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(__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()
@ -14,6 +25,7 @@ function setupInjection(){
// 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
@ -50,7 +62,6 @@ function setupStreams(){
pluginStream.on('close', function () {
reloadStream.write({ method: 'reset' })
})
}
function shouldInjectWeb3(){

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@ -8,6 +8,7 @@ var watch = require('gulp-watch')
var sourcemaps = require('gulp-sourcemaps')
var assign = require('lodash.assign')
var livereload = require('gulp-livereload')
var brfs = require('gulp-brfs')
var del = require('del')
var eslint = require('gulp-eslint')
var fs = require('fs')
@ -144,6 +145,7 @@ function bundleTask(opts) {
// log errors if they happen
.on('error', gutil.log.bind(gutil, 'Browserify Error'))
.pipe(source(opts.filename))
.pipe(brfs())
// optional, remove if you don't need to buffer file contents
.pipe(buffer())
// optional, remove if you dont want sourcemaps

View File

@ -86,6 +86,7 @@
"deep-freeze-strict": "^1.1.1",
"del": "^2.2.0",
"gulp": "github:gulpjs/gulp#4.0",
"gulp-brfs": "^0.1.0",
"gulp-livereload": "^3.8.1",
"gulp-sourcemaps": "^1.6.0",
"gulp-util": "^3.0.7",