wasm-service

This is a simple proof of concept that shows how you could use HTMX and Rust for frontend development. The basic idea in HTMX is that a webserver is being called on interactions with DOM elements, and returning back snippets of HTML that will replace certain DOM elements. Instead of http requests going to a regular web server, this project shows how service workers can intercept calls to a server and return back responses driven from WebAssembly instead.

See the demo here: https://richardanaya.github.io/wasm-service/

You can also find a framework inspired by this PoC here: https://github.com/edezhic/prest

Developing wasm-service

Install & build

Install the WASM target via rustup in order to compile to wasm binaries:

rustup target add wasm32-unknown-unknown

Compile the lib crate into wasm_service.wasm:

cargo build --target wasm32-unknown-unknown --release

Copy the .wasm file to app.wasm in current dir:

cp target/wasm32-unknown-unknown/release/wasm_service.wasm app.wasm

Serve repo root dir on localhost http

Use any method to serve the files from the root dir (in particular index.js, sw.js, and app.wasm). Note you need to serve on localhost or via https for service workers to be enabled. Here's how you can do it with caddy in bash:

caddy run --adapter caddyfile --config - <<< $'http://127.0.0.1:8000 \n log \n root / . \n file_server browse'

Rebuild and run automatically with cargo watch

Install:

cargo install cargo-watch

Build and copy on change:

cargo watch -i app.wasm -x 'build --target wasm32-unknown-unknown --release' -s 'cp target/wasm32-unknown-unknown/release/wasm_service.wasm app.wasm'

Resources for developing with service workers

• Service Worker API @ MDN
• Workers overview @ web.dev
• about:debugging in firefox
• Open serviceworker console about:devtools-toolbox?id=<service-worker-id>&type=worker