@gdmod/web-loader v0.3.0

Web Loader

This browser extension permits to load mods on web games

Development

When working on the API, to test changes in the browser, you need to reimport the api into the extension. The script npm run watch will watch for changes and reimport the API automatically. Note that the manifest in the extension directory is automatically generated. to change it, change the template in this folder.

Installation

Installation instructions for users on the wiki.

Usage

When a page contains a GDevelop game, the extension will automatically patch it to gain access to the whole game. Then you can click on the top right the Extension's Icon. If the current page has a patched GDevelop game, it will let you open a control pannel from which you can control the game.

Internal Work

Injection

It works by Injecting a content script to every page and iframe. This script is sandboxed but has access to the chrome APIs (injector.js). So we set up with the limited access we have a forwarding of window message events and forward it to the all the extension's scripts and pages. Then we use our limited access to document to add a script element that loads a script (injected.js) that will be loaded by the page and not the extension, and therefore has complete access to everything (it runs unsandboxed).

Patching

We now verify if window.gdjs is present. If it is we assume this is a GDevelop game. In that case we define the global object GDAPI and scan for all children of gdjs object having "Code" in its name and a child named func. Those are the event sheets of every scene. We rename the original func to originalFunc and override func with the following:

function(runtimeScene) {
    window.GDAPI.game = runtimeScene.getGame();
    originalFunc(runtimeScene);
}

With that we gain access to the whole game permanently, and with that the control of every scene too.