node:http2

Client and server code uses Node’s normal session and stream APIs:

import { connect, createServer } from 'node:http2';

export function requestStatus(authority) {
    const session = connect(authority);
    const stream = session.request({ ':path': '/status' });
    stream.end();
    return session;
}

export const server = createServer((request, response) => {
    response.writeHead(200, { 'content-type': 'text/plain' });
    response.end(`received ${request.url}`);
});

Select its implementation independently:

jco componentize component.js --wit wit --bundle \
  --with-nodejs-http2-via direct -o component.wasm

By default, cleartext operations fail with ERR_JCO_HTTP2_ADAPTER_REQUIRED; secure operations first require jco:node/tls and fail with ERR_JCO_TLS_ADAPTER_REQUIRED when it is denied. Direct secure sessions and servers obtain one-use configuration handles from the TLS provider. Bind it with createHttp2Host(() => instance.http2Callbacks, tls).

direct mode models sessions, streams, and servers as typed host-owned WIT resources, with a passthrough implementation to NodeJS underneath. The WIT interface used is jco:node/http2-callbacks@0.1.0.

Note

Under WASI p2, Bodies are currently buffered; low-level sockets, priority, push, flow-control windows, and operations that cannot cross the boundary throw explicit errors.

Servers support response trailers through Http2ServerResponse.addTrailers() and setTrailer(), or through stream.respond(headers, { waitForTrailers: true }) followed by stream.sendTrailers() in the wantTrailers event. Both direct and wasi-sockets send the trailers after the buffered body. This supports unary gRPC calls, including grpc-status and application metadata.

Request trailers and incremental response streaming remain unsupported. The Node gRPC example runs the same server source in native Node and in a transpiled component.

The http2-callbacks.outgoing-response WIT record now includes trailers. Update checked-in wit/deps/jco-node-0.1.0/http2.wit copies when rebuilding: Jco adds missing dependency files but does not overwrite existing ones. Custom callback providers must return the new list, which may be empty.

The wasi:sockets implementation also deliberately omits server push, HTTP/1.1 Upgrade: h2c, Unix-domain sockets, and Node’s arbitrary createConnection/custom duplex transport hooks.