1 files changed, 212 insertions, 0 deletions
diff --git a/net/http.ts b/net/http.ts
new file mode 100644
index 000000000..bd45aea0d
--- /dev/null
+++ b/net/http.ts
@@ -0,0 +1,212 @@
+import { listen, Conn, toAsyncIterator, Reader, copy } from "deno";
+import { BufReader, BufState, BufWriter } from "./bufio.ts";
+import { TextProtoReader } from "./textproto.ts";
+import { STATUS_TEXT } from "./http_status";
+import { assert } from "./util";
+
+interface Deferred {
+  promise: Promise<{}>;
+  resolve: () => void;
+  reject: () => void;
+}
+
+function deferred(): Deferred {
+  let resolve, reject;
+  const promise = new Promise((res, rej) => {
+    resolve = res;
+    reject = rej;
+  });
+  return {
+    promise,
+    resolve,
+    reject
+  };
+}
+
+interface ServeEnv {
+  reqQueue: ServerRequest[];
+  serveDeferred: Deferred;
+}
+
+// Continuously read more requests from conn until EOF
+// Mutually calling with maybeHandleReq
+// TODO: make them async function after this change is done
+// https://github.com/tc39/ecma262/pull/1250
+// See https://v8.dev/blog/fast-async
+export function serveConn(env: ServeEnv, conn: Conn) {
+  readRequest(conn).then(maybeHandleReq.bind(null, env, conn));
+}
+function maybeHandleReq(env: ServeEnv, conn: Conn, maybeReq: any) {
+  const [req, _err] = maybeReq;
+  if (_err) {
+    conn.close(); // assume EOF for now...
+    return;
+  }
+  env.reqQueue.push(req); // push req to queue
+  env.serveDeferred.resolve(); // signal while loop to process it
+  // TODO: protection against client req flooding
+  serveConn(env, conn); // try read more (reusing connection)
+}
+
+export async function* serve(addr: string) {
+  const listener = listen("tcp", addr);
+  const env: ServeEnv = {
+    reqQueue: [], // in case multiple promises are ready
+    serveDeferred: deferred()
+  };
+
+  // Routine that keeps calling accept
+  const acceptRoutine = () => {
+    const handleConn = (conn: Conn) => {
+      serveConn(env, conn); // don't block
+      scheduleAccept(); // schedule next accept
+    };
+    const scheduleAccept = () => {
+      listener.accept().then(handleConn);
+    };
+    scheduleAccept();
+  };
+
+  acceptRoutine();
+
+  // Loop hack to allow yield (yield won't work in callbacks)
+  while (true) {
+    await env.serveDeferred.promise;
+    env.serveDeferred = deferred(); // use a new deferred
+    let queueToProcess = env.reqQueue;
+    env.reqQueue = [];
+    for (const result of queueToProcess) {
+      yield result;
+    }
+  }
+  listener.close();
+}
+
+export async function listenAndServe(
+  addr: string,
+  handler: (req: ServerRequest) => void
+) {
+  const server = serve(addr);
+
+  for await (const request of server) {
+    await handler(request);
+  }
+}
+
+export interface Response {
+  status?: number;
+  headers?: Headers;
+  body?: Uint8Array | Reader;
+}
+
+export function setContentLength(r: Response): void {
+  if (!r.headers) {
+    r.headers = new Headers();
+  }
+
+  if (r.body) {
+    if (!r.headers.has("content-length")) {
+      if (r.body instanceof Uint8Array) {
+        const bodyLength = r.body.byteLength;
+        r.headers.append("Content-Length", bodyLength.toString());
+      } else {
+        r.headers.append("Transfer-Encoding", "chunked");
+      }
+    }
+  }
+}
+
+export class ServerRequest {
+  url: string;
+  method: string;
+  proto: string;
+  headers: Headers;
+  w: BufWriter;
+
+  private async _streamBody(body: Reader, bodyLength: number) {
+    const n = await copy(this.w, body);
+    assert(n == bodyLength);
+  }
+
+  private async _streamChunkedBody(body: Reader) {
+    const encoder = new TextEncoder();
+
+    for await (const chunk of toAsyncIterator(body)) {
+      const start = encoder.encode(`${chunk.byteLength.toString(16)}\r\n`);
+      const end = encoder.encode("\r\n");
+      await this.w.write(start);
+      await this.w.write(chunk);
+      await this.w.write(end);
+    }
+
+    const endChunk = encoder.encode("0\r\n\r\n");
+    await this.w.write(endChunk);
+  }
+
+  async respond(r: Response): Promise<void> {
+    const protoMajor = 1;
+    const protoMinor = 1;
+    const statusCode = r.status || 200;
+    const statusText = STATUS_TEXT.get(statusCode);
+    if (!statusText) {
+      throw Error("bad status code");
+    }
+
+    let out = `HTTP/${protoMajor}.${protoMinor} ${statusCode} ${statusText}\r\n`;
+
+    setContentLength(r);
+
+    if (r.headers) {
+      for (const [key, value] of r.headers) {
+        out += `${key}: ${value}\r\n`;
+      }
+    }
+    out += "\r\n";
+
+    const header = new TextEncoder().encode(out);
+    let n = await this.w.write(header);
+    assert(header.byteLength == n);
+
+    if (r.body) {
+      if (r.body instanceof Uint8Array) {
+        n = await this.w.write(r.body);
+        assert(r.body.byteLength == n);
+      } else {
+        if (r.headers.has("content-length")) {
+          await this._streamBody(
+            r.body,
+            parseInt(r.headers.get("content-length"))
+          );
+        } else {
+          await this._streamChunkedBody(r.body);
+        }
+      }
+    }
+
+    await this.w.flush();
+  }
+}
+
+async function readRequest(c: Conn): Promise<[ServerRequest, BufState]> {
+  const bufr = new BufReader(c);
+  const bufw = new BufWriter(c);
+  const req = new ServerRequest();
+  req.w = bufw;
+  const tp = new TextProtoReader(bufr);
+
+  let s: string;
+  let err: BufState;
+
+  // First line: GET /index.html HTTP/1.0
+  [s, err] = await tp.readLine();
+  if (err) {
+    return [null, err];
+  }
+  [req.method, req.url, req.proto] = s.split(" ", 3);
+
+  [req.headers, err] = await tp.readMIMEHeader();
+
+  // TODO: handle body
+
+  return [req, err];
+}