Experimental Preview
git clone https://github.com/cloudflare/workers-rs
cd workers-rs/examples/emscripten
npx wrangler devA Worker built with worker-build --emscripten for wasm32-unknown-emscripten.
The target brings Emscripten's libc and in-memory filesystem, so std::fs,
std::io and code written around files work unchanged.
This Worker is a word-frequency counter that works the way a command-line tool
would: the POSTed text is written to a file under std::env::temp_dir(), read
back line by line, and the report is written to a second file and returned
along with a directory listing.
npx wrangler dev
curl -X POST --data-binary @README.md http://localhost:8787/An emscripten build links a bin target: rustc drives emcc as the linker,
which runs wasm-bindgen as a post-link step. So handlers live in
src/main.rs with an empty fn main() {}, and there is no cdylib.
rust-toolchain.toml selects beta, and the [patch.crates-io] block points
wasm-bindgen at the checkout matching the CLI emcc runs.
Take a look at the emscripten-tokio and emscripten-tcp examples for async IO and TCP sockets examples.
See the [README](../../worker-build/README.md#emscripten, or wasm-bindgen Emscripten documentation for the toolchain details.
