1 files changed, 534 insertions, 0 deletions
diff --git a/ext/http/00_serve.js b/ext/http/00_serve.js
new file mode 100644
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--- /dev/null
+++ b/ext/http/00_serve.js
@@ -0,0 +1,534 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+const core = globalThis.Deno.core;
+const primordials = globalThis.__bootstrap.primordials;
+
+const { BadResourcePrototype } = core;
+import { InnerBody } from "ext:deno_fetch/22_body.js";
+import { Event } from "ext:deno_web/02_event.js";
+import {
+  fromInnerResponse,
+  newInnerResponse,
+  toInnerResponse,
+} from "ext:deno_fetch/23_response.js";
+import { fromInnerRequest } from "ext:deno_fetch/23_request.js";
+import { AbortController } from "ext:deno_web/03_abort_signal.js";
+import {
+  _eventLoop,
+  _idleTimeoutDuration,
+  _idleTimeoutTimeout,
+  _protocol,
+  _readyState,
+  _rid,
+  _role,
+  _server,
+  _serverHandleIdleTimeout,
+  SERVER,
+  WebSocket,
+} from "ext:deno_websocket/01_websocket.js";
+import {
+  Deferred,
+  getReadableStreamResourceBacking,
+  readableStreamForRid,
+  ReadableStreamPrototype,
+} from "ext:deno_web/06_streams.js";
+const {
+  ObjectPrototypeIsPrototypeOf,
+  SafeSet,
+  SafeSetIterator,
+  SetPrototypeAdd,
+  SetPrototypeDelete,
+  Symbol,
+  TypeError,
+  Uint8ArrayPrototype,
+  Uint8Array,
+} = primordials;
+
+const _upgraded = Symbol("_upgraded");
+
+function internalServerError() {
+  // "Internal Server Error"
+  return new Response(
+    new Uint8Array([
+      73,
+      110,
+      116,
+      101,
+      114,
+      110,
+      97,
+      108,
+      32,
+      83,
+      101,
+      114,
+      118,
+      101,
+      114,
+      32,
+      69,
+      114,
+      114,
+      111,
+      114,
+    ]),
+    { status: 500 },
+  );
+}
+
+// Used to ensure that user returns a valid response (but not a different response) from handlers that are upgraded.
+const UPGRADE_RESPONSE_SENTINEL = fromInnerResponse(
+  newInnerResponse(101),
+  "immutable",
+);
+
+class InnerRequest {
+  #slabId;
+  #context;
+  #methodAndUri;
+  #streamRid;
+  #body;
+  #upgraded;
+
+  constructor(slabId, context) {
+    this.#slabId = slabId;
+    this.#context = context;
+    this.#upgraded = false;
+  }
+
+  close() {
+    if (this.#streamRid !== undefined) {
+      core.close(this.#streamRid);
+      this.#streamRid = undefined;
+    }
+    this.#slabId = undefined;
+  }
+
+  get [_upgraded]() {
+    return this.#upgraded;
+  }
+
+  _wantsUpgrade(upgradeType, ...originalArgs) {
+    // upgradeHttp is async
+    // TODO(mmastrac)
+    if (upgradeType == "upgradeHttp") {
+      throw "upgradeHttp is unavailable in Deno.serve at this time";
+    }
+
+    // upgradeHttpRaw is async
+    // TODO(mmastrac)
+    if (upgradeType == "upgradeHttpRaw") {
+      throw "upgradeHttp is unavailable in Deno.serve at this time";
+    }
+
+    // upgradeWebSocket is sync
+    if (upgradeType == "upgradeWebSocket") {
+      const response = originalArgs[0];
+      const ws = originalArgs[1];
+
+      this.url();
+      this.headerList;
+      this.close();
+
+      const goAhead = new Deferred();
+      this.#upgraded = () => {
+        goAhead.resolve();
+      };
+
+      // Start the upgrade in the background.
+      (async () => {
+        try {
+          // Returns the connection and extra bytes, which we can pass directly to op_ws_server_create
+          const upgrade = await core.opAsync2(
+            "op_upgrade",
+            this.#slabId,
+            response.headerList,
+          );
+          const wsRid = core.ops.op_ws_server_create(upgrade[0], upgrade[1]);
+
+          // We have to wait for the go-ahead signal
+          await goAhead;
+
+          ws[_rid] = wsRid;
+          ws[_readyState] = WebSocket.OPEN;
+          ws[_role] = SERVER;
+          const event = new Event("open");
+          ws.dispatchEvent(event);
+
+          ws[_eventLoop]();
+          if (ws[_idleTimeoutDuration]) {
+            ws.addEventListener(
+              "close",
+              () => clearTimeout(ws[_idleTimeoutTimeout]),
+            );
+          }
+          ws[_serverHandleIdleTimeout]();
+        } catch (error) {
+          const event = new ErrorEvent("error", { error });
+          ws.dispatchEvent(event);
+        }
+      })();
+      return { response: UPGRADE_RESPONSE_SENTINEL, socket: ws };
+    }
+  }
+
+  url() {
+    if (this.#methodAndUri === undefined) {
+      if (this.#slabId === undefined) {
+        throw new TypeError("request closed");
+      }
+      // TODO(mmastrac): This is quite slow as we're serializing a large number of values. We may want to consider
+      // splitting this up into multiple ops.
+      this.#methodAndUri = core.ops.op_get_request_method_and_url(this.#slabId);
+    }
+
+    const path = this.#methodAndUri[2];
+
+    // * is valid for OPTIONS
+    if (path === "*") {
+      return "*";
+    }
+
+    // If the path is empty, return the authority (valid for CONNECT)
+    if (path == "") {
+      return this.#methodAndUri[1];
+    }
+
+    // CONNECT requires an authority
+    if (this.#methodAndUri[0] == "CONNECT") {
+      return this.#methodAndUri[1];
+    }
+
+    const hostname = this.#methodAndUri[1];
+    if (hostname) {
+      // Construct a URL from the scheme, the hostname, and the path
+      return this.#context.scheme + hostname + path;
+    }
+
+    // Construct a URL from the scheme, the fallback hostname, and the path
+    return this.#context.scheme + this.#context.fallbackHost + path;
+  }
+
+  get remoteAddr() {
+    if (this.#methodAndUri === undefined) {
+      if (this.#slabId === undefined) {
+        throw new TypeError("request closed");
+      }
+      this.#methodAndUri = core.ops.op_get_request_method_and_url(this.#slabId);
+    }
+    return {
+      transport: "tcp",
+      hostname: this.#methodAndUri[3],
+      port: this.#methodAndUri[4],
+    };
+  }
+
+  get method() {
+    if (this.#methodAndUri === undefined) {
+      if (this.#slabId === undefined) {
+        throw new TypeError("request closed");
+      }
+      this.#methodAndUri = core.ops.op_get_request_method_and_url(this.#slabId);
+    }
+    return this.#methodAndUri[0];
+  }
+
+  get body() {
+    if (this.#slabId === undefined) {
+      throw new TypeError("request closed");
+    }
+    if (this.#body !== undefined) {
+      return this.#body;
+    }
+    // If the method is GET or HEAD, we do not want to include a body here, even if the Rust
+    // side of the code is willing to provide it to us.
+    if (this.method == "GET" || this.method == "HEAD") {
+      this.#body = null;
+      return null;
+    }
+    this.#streamRid = core.ops.op_read_request_body(this.#slabId);
+    this.#body = new InnerBody(readableStreamForRid(this.#streamRid, false));
+    return this.#body;
+  }
+
+  get headerList() {
+    if (this.#slabId === undefined) {
+      throw new TypeError("request closed");
+    }
+    return core.ops.op_get_request_headers(this.#slabId);
+  }
+
+  get slabId() {
+    return this.#slabId;
+  }
+}
+
+class CallbackContext {
+  scheme;
+  fallbackHost;
+  serverRid;
+  closed;
+
+  initialize(args) {
+    this.serverRid = args[0];
+    this.scheme = args[1];
+    this.fallbackHost = args[2];
+    this.closed = false;
+  }
+
+  close() {
+    try {
+      this.closed = true;
+      core.tryClose(this.serverRid);
+    } catch {
+      // Pass
+    }
+  }
+}
+
+function fastSyncResponseOrStream(req, respBody) {
+  if (respBody === null || respBody === undefined) {
+    // Don't set the body
+    return null;
+  }
+
+  const stream = respBody.streamOrStatic;
+  const body = stream.body;
+
+  if (ObjectPrototypeIsPrototypeOf(Uint8ArrayPrototype, body)) {
+    core.ops.op_set_response_body_bytes(req, body);
+    return null;
+  }
+
+  if (typeof body === "string") {
+    core.ops.op_set_response_body_text(req, body);
+    return null;
+  }
+
+  // At this point in the response it needs to be a stream
+  if (!ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, stream)) {
+    throw TypeError("invalid response");
+  }
+  const resourceBacking = getReadableStreamResourceBacking(stream);
+  if (resourceBacking) {
+    core.ops.op_set_response_body_resource(
+      req,
+      resourceBacking.rid,
+      resourceBacking.autoClose,
+    );
+    return null;
+  }
+
+  return stream;
+}
+
+async function asyncResponse(responseBodies, req, status, stream) {
+  const responseRid = core.ops.op_set_response_body_stream(req);
+  SetPrototypeAdd(responseBodies, responseRid);
+  const reader = stream.getReader();
+  core.ops.op_set_promise_complete(req, status);
+  try {
+    while (true) {
+      const { value, done } = await reader.read();
+      if (done) {
+        break;
+      }
+      await core.writeAll(responseRid, value);
+    }
+  } catch (error) {
+    await reader.cancel(error);
+  } finally {
+    core.tryClose(responseRid);
+    SetPrototypeDelete(responseBodies, responseRid);
+    reader.releaseLock();
+  }
+}
+
+/**
+ * Maps the incoming request slab ID to a fully-fledged Request object, passes it to the user-provided
+ * callback, then extracts the response that was returned from that callback. The response is then pulled
+ * apart and handled on the Rust side.
+ *
+ * This function returns a promise that will only reject in the case of abnormal exit.
+ */
+function mapToCallback(responseBodies, context, signal, callback, onError) {
+  return async function (req) {
+    const innerRequest = new InnerRequest(req, context);
+    const request = fromInnerRequest(innerRequest, signal, "immutable");
+
+    // Get the response from the user-provided callback. If that fails, use onError. If that fails, return a fallback
+    // 500 error.
+    let response;
+    try {
+      response = await callback(request, {
+        remoteAddr: innerRequest.remoteAddr,
+      });
+    } catch (error) {
+      try {
+        response = await onError(error);
+      } catch (error) {
+        console.error("Exception in onError while handling exception", error);
+        response = internalServerError();
+      }
+    }
+
+    const inner = toInnerResponse(response);
+    if (innerRequest[_upgraded]) {
+      // We're done here as the connection has been upgraded during the callback and no longer requires servicing.
+      if (response !== UPGRADE_RESPONSE_SENTINEL) {
+        console.error("Upgrade response was not returned from callback");
+        context.close();
+      }
+      innerRequest[_upgraded]();
+      return;
+    }
+
+    // Did everything shut down while we were waiting?
+    if (context.closed) {
+      innerRequest.close();
+      return;
+    }
+
+    const status = inner.status;
+    const headers = inner.headerList;
+    if (headers && headers.length > 0) {
+      if (headers.length == 1) {
+        core.ops.op_set_response_header(req, headers[0][0], headers[0][1]);
+      } else {
+        core.ops.op_set_response_headers(req, headers);
+      }
+    }
+
+    // Attempt to response quickly to this request, otherwise extract the stream
+    const stream = fastSyncResponseOrStream(req, inner.body);
+    if (stream !== null) {
+      // Handle the stream asynchronously
+      await asyncResponse(responseBodies, req, status, stream);
+    } else {
+      core.ops.op_set_promise_complete(req, status);
+    }
+
+    innerRequest.close();
+  };
+}
+
+async function serve(arg1, arg2) {
+  let options = undefined;
+  let handler = undefined;
+  if (typeof arg1 === "function") {
+    handler = arg1;
+    options = arg2;
+  } else if (typeof arg2 === "function") {
+    handler = arg2;
+    options = arg1;
+  } else {
+    options = arg1;
+  }
+  if (handler === undefined) {
+    if (options === undefined) {
+      throw new TypeError(
+        "No handler was provided, so an options bag is mandatory.",
+      );
+    }
+    handler = options.handler;
+  }
+  if (typeof handler !== "function") {
+    throw new TypeError("A handler function must be provided.");
+  }
+  if (options === undefined) {
+    options = {};
+  }
+
+  const wantsHttps = options.cert || options.key;
+  const signal = options.signal;
+  const onError = options.onError ?? function (error) {
+    console.error(error);
+    return internalServerError();
+  };
+  const listenOpts = {
+    hostname: options.hostname ?? "0.0.0.0",
+    port: options.port ?? (wantsHttps ? 9000 : 8000),
+    reusePort: options.reusePort ?? false,
+  };
+
+  const abortController = new AbortController();
+
+  const responseBodies = new SafeSet();
+  const context = new CallbackContext();
+  const callback = mapToCallback(
+    responseBodies,
+    context,
+    abortController.signal,
+    handler,
+    onError,
+  );
+
+  if (wantsHttps) {
+    if (!options.cert || !options.key) {
+      throw new TypeError(
+        "Both cert and key must be provided to enable HTTPS.",
+      );
+    }
+    listenOpts.cert = options.cert;
+    listenOpts.key = options.key;
+    listenOpts.alpnProtocols = ["h2", "http/1.1"];
+    const listener = Deno.listenTls(listenOpts);
+    listenOpts.port = listener.addr.port;
+    context.initialize(core.ops.op_serve_http(
+      listener.rid,
+    ));
+  } else {
+    const listener = Deno.listen(listenOpts);
+    listenOpts.port = listener.addr.port;
+    context.initialize(core.ops.op_serve_http(
+      listener.rid,
+    ));
+  }
+
+  signal?.addEventListener(
+    "abort",
+    () => context.close(),
+    { once: true },
+  );
+
+  const onListen = options.onListen ?? function ({ port }) {
+    // If the hostname is "0.0.0.0", we display "localhost" in console
+    // because browsers in Windows don't resolve "0.0.0.0".
+    // See the discussion in https://github.com/denoland/deno_std/issues/1165
+    const hostname = listenOpts.hostname == "0.0.0.0"
+      ? "localhost"
+      : listenOpts.hostname;
+    console.log(`Listening on ${context.scheme}${hostname}:${port}/`);
+  };
+
+  onListen({ port: listenOpts.port });
+
+  while (true) {
+    const rid = context.serverRid;
+    let req;
+    try {
+      req = await core.opAsync("op_http_wait", rid);
+    } catch (error) {
+      if (ObjectPrototypeIsPrototypeOf(BadResourcePrototype, error)) {
+        break;
+      }
+      throw new Deno.errors.Http(error);
+    }
+    if (req === 0xffffffff) {
+      break;
+    }
+    callback(req).catch((error) => {
+      // Abnormal exit
+      console.error(
+        "Terminating Deno.serve loop due to unexpected error",
+        error,
+      );
+      context.close();
+    });
+  }
+
+  for (const streamRid of new SafeSetIterator(responseBodies)) {
+    core.tryClose(streamRid);
+  }
+}
+
+export { serve };