WASM-GIT

(WASM should be pronounced like awesome starting with a W ).

GIT for nodejs and the browser using libgit2 compiled to WebAssembly with Emscripten.

Demo in the browser

A simple demo in the browser can be found at:

https://githttpserverdemo.petersalomonsen.usw1.kubesail.io/

Please do not abuse, this is open for you to test and see the proof of concept

The sources for the demo can be found in the githttpserver project, which is a simple git server deployable to kubernetes. Showing basic operations like cloning, edit files, add and commit, push and pull.

Example WebWorker with pre built binaries

For running in the browser you should have your git interaction code in a webworker. This is because of the use of synchronous http requests and long running operations that would block if running on the main thread.

Here's an example of a simple webworker that uses pre-built binaries from https://unpkg.com/[email protected]/

var Module = {
    locateFile: function(s) {
      return 'https://unpkg.com/[email protected]/' + s;
    }
};

importScripts('https://unpkg.com/[email protected]/lg2.js');

Module.onRuntimeInitialized = () => {
    const lg = Module;

    FS.mkdir('/working');
    FS.mount(MEMFS, { }, '/working');
    FS.chdir('/working');    

    FS.writeFile('/home/web_user/.gitconfig', '[user]\n' +
                'name = Test User\n' +
                'email = [email protected]');

    // clone a local git repository and make some commits

    lg.callMain(['clone',`http://localhost:5000/test.git`, 'testrepo']);

    FS.readdir('testrepo');
}

You'll start the worker from your html with the tag:

<script>new Worker('yourworker.js')</script>;

The example above expects to find a git repository at http://localhost:5000/test.git. If you want to clone from github you'd need a proxy running locally because of CORS restrictions that would prevent you accessing github directly. For testing you can use the proxy found in examples/webserverwithgithubproxy.js

Use from nodejs with pre built binaries

You may install the npm package containing the binaries:

npm install wasm-git

example source code for cloning a repository from github:

const lg = require('./node_modules/wasm-git/lg2.js');

lg.onRuntimeInitialized = () => {
    const FS = lg.FS;
    const MEMFS = FS.filesystems.MEMFS;

    FS.mkdir('/working');
    FS.mount(MEMFS, { }, '/working');
    FS.chdir('/working');    

    FS.writeFile('/home/web_user/.gitconfig', '[user]\n' +
                'name = Test User\n' +
                'email = [email protected]');
    
    // clone a repository from github
    lg.callMain(['clone','https://github.com/torch2424/made-with-webassembly.git', 'made-with-webassembly']);
    FS.readdir('made-with-webassembly');
}

Building

IMPORTANT: This depends on the following mmap fixes for emscripten:

• emscripten-core/emscripten#10095
• emscripten-core/emscripten#10526
• emscripten-core/emscripten#10782

for using with NODEFS you'll also need emscripten-core/emscripten#10669

All of these pull requests are merged to emscripten master as of 2020-03-29.

Run setup.sh first to download libgit2 and apply patches.

The script in emscriptenbuild/build.sh shows how to configure and build, and you'll find the resulting lg2.js / lg2.wasm under the generated emscriptenbuild/examples folder.

An example of interacting with libgit2 from nodejs can be found in examples/example_node.js.

An example for the browser (using webworkers) can be found in examples/example_webworker.js. You can start a webserver for this by running the examples/webserverwithgithubproxy.js script, which will launch a http server at http://localhost:5000 with a proxy to github. Proxy instead of direct calls is needed because of CORS restrictions in a browser environment.