browser-echo

iroh browser echo demo

This example runs iroh in the browser, compiled to web assembly. The example uses a custom Echo protocol: You connect to remote node, send some data, and the remote node sends back the same data. The protocol may be used both from the browser and from the command line, and browser and cli nodes can connect to each other.

The protocol and setup code is shared between the browser and the CLI.

Run the browser version:

You can try out the deployed example. To build and run it yourself, follow these steps:

$ cargo install wasm-bindgen-cli
$ rustup target install wasm32-unknown-unknown
$ npm install
$ npm run build
$ npm run serve

Then, open http://localhost:8080. The app will print instructions on how to connect and accept connections.

To build in release mode and apply optimizations to reduce the wasm size, run npm run build:release instead.

Run the CLI version:

To accept connections:

cargo run --features cli -- accept

To initiate a connection:

cargo run --features cli -- connect <NODE-ID> <PAYLOAD>

Navigate the code

This folder contains a single Rust crate that can be compiled to both webassembly for the browser and to a commad line.

• The shared code between WASM and CLI lives in src/node.rs.
• A WASM-only wrapper around the EchoNode defined there lives in src/wasm.rs. It mostly is concerned with converting types to browser-supported equivalents.
• The CLI binary lives in src/bin/cli.rs

Apart from the rust crate, we have a little HTML, CSS and JavaScript for the demo app. There's no further external dependencies used. The code lives in [public].

Running npm run build first compiles the crate to WASM, then creates the JavaScript browser bindings with wasm-bindgen, and puts the result into public/wasm, from where the wasm is imported in the main.js.