Welcome to the WebAssembly + JavaScript binding for the Rust matrix-sdk-crypto library! WebAssembly can run anywhere, but these bindings are designed to run on a JavaScript host. These bindings are part of the matrix-rust-sdk project, which is a library implementation of a Matrix client-server.

matrix-sdk-crypto is a no-network-IO implementation of a state machine, named OlmMachine, that handles E2EE (End-to-End Encryption) for Matrix clients.

1. Install in your project:

   npm install --save @matrix-org/matrix-sdk-crypto-wasm
   

   or:

   yarn add @matrix-org/matrix-sdk-crypto-wasm
   

2. Import the library into your project and initialise it.

   On Web platforms, the library must be initialised by calling initAsync before it can be used, else it will throw an error. This is also recommended on other platforms, as it allows the WebAssembly module to be loaded asynchronously.

   import { initAsync, Tracing, LoggerLevel, OlmMachine, UserId, DeviceId } from "@matrix-org/matrix-sdk-crypto-wasm";
   async function loadCrypto(userId, deviceId) {
       // Do this before any other calls to the library
       await initAsync();
       // Optional: enable tracing in the rust-sdk
       new Tracing(LoggerLevel.Trace).turnOn();
       // Create a new OlmMachine
       //
       // The following will use an in-memory store. It is recommended to use
       // indexedDB where that is available.
       // See https://matrix-org.github.io/matrix-rust-sdk-crypto-wasm/classes/OlmMachine.html#initialize
       const olmMachine = await OlmMachine.initialize(new UserId(userId), new DeviceId(deviceId));
       return olmMachine;
   }

   See the API documentation for more information.

3. Build your project.

   The packaging of this library aims to "just work" the same as any plain-javascript project would: it includes separate entry points for Node.js-like environments (which read the WASM file via fs.readFile()) and web-like environments (which download the WASM file with fetch()). There are both CommonJS and ES Module entry points for each environment; an appropriate entrypoint should be selected automatically.

   If your environment supports the experimental ES Module Integration Proposal for WebAssembly, you can instead use that, by setting the matrix-org:wasm-esm custom export condition. This is only supported when the library is imported as an ES Module. For example:

   • In Webpack, set experiments.asyncWebAssembly to true and resolve.conditionNames to ["matrix-org:wasm-esm", "..."] (the "..." preserves default condition names).
   • In Node.js, invoke with commandline arguments --experimental-wasm-modules --conditions=wasm-esm.

These WebAssembly bindings are written in Rust. To build them, you need to install the Rust compiler, see the Install Rust Page. Then, the workflow is pretty classical by using yarn, see the Downloading and installing Node.js and npm Page and installing yarn.

Once the Rust compiler, Node.js and yarn are installed, you can run the following commands:

$ yarn install
$ yarn build  # or 'yarn build:dev' to make an unoptimised build
$ yarn test

The compiled output should be generated in the pkg/ directory.

To build based on a local matrix-rust-sdk, add something like this to your .cargo/config file:

[patch.'https://github.com/matrix-org/matrix-rust-sdk']
matrix-sdk-base = { path = "../matrix-rust-sdk/crates/matrix-sdk-base" }
matrix-sdk-common = { path = "../matrix-rust-sdk/crates/matrix-sdk-common" }
matrix-sdk-crypto = { path = "../matrix-rust-sdk/crates/matrix-sdk-crypto" }
matrix-sdk-indexeddb = { path = "../matrix-rust-sdk/crates/matrix-sdk-indexeddb" }
matrix-sdk-qrcode = { path = "../matrix-rust-sdk/crates/matrix-sdk-qrcode" }

The documentation can be found online.

To generate the documentation locally, please run the following command:

$ yarn doc

The documentation is generated in the ./docs directory.

Thank you! See the contributing doc for more info.