/wasi-http-test-jco

Primary LanguageRust

This is a quick proof of concept getting the wasi:http functionality working.

The main things required to get this to work:

  • Save the wasi_snapshot_preview1.reactor.wasm binary into the runtime/ dir and then use it with the --adapt param of wasm-tools component new to include the wasi preview1 functionality into my binary. The pre-build binary was sourced from a tagged wasmtime release (16.0.0).
  • Include all necessary wasi:* wit files in the runtime/wit/deps directory. These were sourced from the wasi-http GH repo and the wasi:http specific ones had package wasi:http@0.2.0-rc-2023-12-05; added at the top of each to make them easily referenceable.
  • We add a import wasi:http/outgoing-handler@0.2.0-rc-2023-12-05; statement to the world so that the Rust parts of the wasi:http library are generated and we can reference them like:
use wasi::http::outgoing_handler::handle;
use wasi::http::types::{
    ErrorCode, Fields, FutureIncomingResponse, IncomingBody, IncomingResponse, OutgoingRequest,
    RequestOptions, Scheme,
};
  • We then use the wasi:http library to construct an OutgoingRequest, send it, block the thread awaiting the response using a Pollable subscribed to via the FutureIncomingResponse, and then parse out the body of the response.
  • Add "@bytecodealliance/preview2-shim" to our package.json as a dependency so jco can access its wasi shims.

To execute the code run:

npm run build && npm run test