feat(fetch): implement abort (#10863)

This commit introduces fetch aborting via an AbortSignal.

extensions/fetch/11_streams.js

@@ -3227,6 +3227,10 @@
     }
   }
 
+  function errorReadableStream(stream, e) {
+    readableStreamDefaultControllerError(stream[_controller], e);
+  }
+
   /** @template R */
   class ReadableStreamGenericReader {
     /** @type {Deferred<void>} */
@@ -3873,6 +3877,7 @@
   window.__bootstrap.streams = {
     // Non-Public
     isReadableStreamDisturbed,
+    errorReadableStream,
     // Exposed in global runtime scope
     ByteLengthQueuingStrategy,
     CountQueuingStrategy,

extensions/fetch/22_body.js

@@ -20,7 +20,8 @@
   const { parseFormData, formDataFromEntries, encodeFormData } =
     globalThis.__bootstrap.formData;
   const mimesniff = globalThis.__bootstrap.mimesniff;
-  const { isReadableStreamDisturbed } = globalThis.__bootstrap.streams;
+  const { isReadableStreamDisturbed, errorReadableStream } =
+    globalThis.__bootstrap.streams;
 
   class InnerBody {
     /** @type {ReadableStream<Uint8Array> | { body: Uint8Array, consumed: boolean }} */
@@ -106,6 +107,22 @@
       }
     }
 
+    cancel(error) {
+      if (this.streamOrStatic instanceof ReadableStream) {
+        this.streamOrStatic.cancel(error);
+      } else {
+        this.streamOrStatic.consumed = true;
+      }
+    }
+
+    error(error) {
+      if (this.streamOrStatic instanceof ReadableStream) {
+        errorReadableStream(this.streamOrStatic, error);
+      } else {
+        this.streamOrStatic.consumed = true;
+      }
+    }
+
     /**
      * @returns {InnerBody}
      */

extensions/fetch/23_request.js

@@ -26,9 +26,11 @@
     getDecodeSplitHeader,
   } = window.__bootstrap.headers;
   const { HttpClient } = window.__bootstrap.fetch;
+  const abortSignal = window.__bootstrap.abortSignal;
 
   const _request = Symbol("request");
   const _headers = Symbol("headers");
+  const _signal = Symbol("signal");
   const _mimeType = Symbol("mime type");
   const _body = Symbol("body");
 
@@ -145,6 +147,8 @@
     [_request];
     /** @type {Headers} */
     [_headers];
+    /** @type {AbortSignal} */
+    [_signal];
     get [_mimeType]() {
       let charset = null;
       let essence = null;
@@ -206,6 +210,9 @@
       let request;
       const baseURL = getLocationHref();
 
+      // 4.
+      let signal = null;
+
       // 5.
       if (typeof input === "string") {
         const parsedURL = new URL(input, baseURL);
@@ -213,8 +220,12 @@
       } else { // 6.
         if (!(input instanceof Request)) throw new TypeError("Unreachable");
         request = input[_request];
+        signal = input[_signal];
       }
 
+      // 12.
+      // TODO(lucacasonato): create a copy of `request`
+
       // 22.
       if (init.redirect !== undefined) {
         request.redirectMode = init.redirect;
@@ -227,6 +238,11 @@
         request.method = method;
       }
 
+      // 26.
+      if (init.signal !== undefined) {
+        signal = init.signal;
+      }
+
       // NOTE: non standard extension. This handles Deno.HttpClient parameter
       if (init.client !== undefined) {
         if (init.client !== null && !(init.client instanceof HttpClient)) {
@@ -242,6 +258,12 @@
       // 27.
       this[_request] = request;
 
+      // 28.
+      this[_signal] = abortSignal.newSignal();
+      if (signal !== null) {
+        abortSignal.follow(this[_signal], signal);
+      }
+
       // 29.
       this[_headers] = headersFromHeaderList(request.headerList, "request");
 
@@ -299,6 +321,9 @@
 
       // 40.
       request.body = finalBody;
+
+      // 41.
+      // TODO(lucacasonato): Extranious? https://github.com/whatwg/fetch/issues/1249
     }
 
     get method() {
@@ -321,13 +346,24 @@
       return this[_request].redirectMode;
     }
 
+    get signal() {
+      webidl.assertBranded(this, Request);
+      return this[_signal];
+    }
+
     clone() {
       webidl.assertBranded(this, Request);
       if (this[_body] && this[_body].unusable()) {
         throw new TypeError("Body is unusable.");
       }
       const newReq = cloneInnerRequest(this[_request]);
-      return fromInnerRequest(newReq, guardFromHeaders(this[_headers]));
+      const newSignal = abortSignal.newSignal();
+      abortSignal.follow(newSignal, this[_signal]);
+      return fromInnerRequest(
+        newReq,
+        newSignal,
+        guardFromHeaders(this[_headers]),
+      );
     }
 
     get [Symbol.toStringTag]() {
@@ -364,6 +400,10 @@
     enumerable: true,
     configurable: true,
   });
+  Object.defineProperty(Request.prototype, "signal", {
+    enumerable: true,
+    configurable: true,
+  });
   Object.defineProperty(Request.prototype, "clone", {
     enumerable: true,
     writable: true,
@@ -403,6 +443,12 @@
         ),
       },
       { key: "redirect", converter: webidl.converters["RequestRedirect"] },
+      {
+        key: "signal",
+        converter: webidl.createNullableConverter(
+          webidl.converters["AbortSignal"],
+        ),
+      },
       { key: "client", converter: webidl.converters.any },
     ],
   );
@@ -420,9 +466,10 @@
    * @param {"request" | "immutable" | "request-no-cors" | "response" | "none"} guard
    * @returns {Request}
    */
-  function fromInnerRequest(inner, guard) {
+  function fromInnerRequest(inner, signal, guard) {
     const request = webidl.createBranded(Request);
     request[_request] = inner;
+    request[_signal] = signal;
     request[_headers] = headersFromHeaderList(inner.headerList, guard);
     return request;
   }

extensions/fetch/23_response.js

@@ -48,6 +48,7 @@
    * @property {string} statusMessage
    * @property {[string, string][]} headerList
    * @property {null | typeof __window.bootstrap.fetchBody.InnerBody} body
+   * @property {boolean} aborted
    * @property {string} [error]
    */
 
@@ -92,12 +93,14 @@
       urlList,
       status: response.status,
       statusMessage: response.statusMessage,
+      aborted: response.aborted,
     };
   }
 
   const defaultInnerResponse = {
     type: "default",
     body: null,
+    aborted: false,
     url() {
       if (this.urlList.length == 0) return null;
       return this.urlList[this.urlList.length - 1];
@@ -128,6 +131,15 @@
     return resp;
   }
 
+  /**
+   * @returns {InnerResponse}
+   */
+  function abortedNetworkError() {
+    const resp = networkError("aborted");
+    resp.aborted = true;
+    return resp;
+  }
+
   class Response {
     /** @type {InnerResponse} */
     [_response];
@@ -446,4 +458,5 @@
   window.__bootstrap.fetch.redirectStatus = redirectStatus;
   window.__bootstrap.fetch.nullBodyStatus = nullBodyStatus;
   window.__bootstrap.fetch.networkError = networkError;
+  window.__bootstrap.fetch.abortedNetworkError = abortedNetworkError;
 })(globalThis);

extensions/fetch/26_fetch.js

@@ -15,14 +15,18 @@
   const core = window.Deno.core;
   const webidl = window.__bootstrap.webidl;
   const { byteLowerCase } = window.__bootstrap.infra;
+  const { errorReadableStream } = window.__bootstrap.streams;
   const { InnerBody, extractBody } = window.__bootstrap.fetchBody;
   const {
     toInnerRequest,
+    toInnerResponse,
     fromInnerResponse,
     redirectStatus,
     nullBodyStatus,
     networkError,
+    abortedNetworkError,
   } = window.__bootstrap.fetch;
+  const abortSignal = window.__bootstrap.abortSignal;
 
   const REQUEST_BODY_HEADER_NAMES = [
     "content-encoding",
@@ -68,10 +72,26 @@
 
   /**
    * @param {number} responseBodyRid
+   * @param {AbortSignal} [terminator]
    * @returns {ReadableStream<Uint8Array>}
    */
-  function createResponseBodyStream(responseBodyRid) {
-    return new ReadableStream({
+  function createResponseBodyStream(responseBodyRid, terminator) {
+    function onAbort() {
+      if (readable) {
+        errorReadableStream(
+          readable,
+          new DOMException("Ongoing fetch was aborted.", "AbortError"),
+        );
+      }
+      try {
+        core.close(responseBodyRid);
+      } catch (_) {
+        // might have already been closed
+      }
+    }
+    // TODO(lucacasonato): clean up registration
+    terminator[abortSignal.add](onAbort);
+    const readable = new ReadableStream({
       type: "bytes",
       async pull(controller) {
         try {
@@ -88,28 +108,45 @@
           } else {
             // We have reached the end of the body, so we close the stream.
             controller.close();
+            try {
               core.close(responseBodyRid);
+            } catch (_) {
+              // might have already been closed
+            }
           }
         } catch (err) {
+          if (terminator.aborted) {
+            controller.error(
+              new DOMException("Ongoing fetch was aborted.", "AbortError"),
+            );
+          } else {
             // There was an error while reading a chunk of the body, so we
             // error.
             controller.error(err);
-          controller.close();
+          }
+          try {
             core.close(responseBodyRid);
+          } catch (_) {
+            // might have already been closed
+          }
         }
       },
       cancel() {
-        core.close(responseBodyRid);
+        if (!terminator.aborted) {
+          terminator[abortSignal.signalAbort]();
+        }
       },
     });
+    return readable;
   }
 
   /**
    * @param {InnerRequest} req
    * @param {boolean} recursive
+   * @param {AbortSignal} terminator
    * @returns {Promise<InnerResponse>}
    */
-  async function mainFetch(req, recursive) {
+  async function mainFetch(req, recursive, terminator) {
     /** @type {ReadableStream<Uint8Array> | Uint8Array | null} */
     let reqBody = null;
     if (req.body !== null) {
@@ -130,7 +167,7 @@
       }
     }
 
-    const { requestRid, requestBodyRid } = opFetch({
+    const { requestRid, requestBodyRid, cancelHandleRid } = opFetch({
       method: req.method,
       url: req.currentUrl(),
       headers: req.headerList,
@@ -138,6 +175,20 @@
       hasBody: reqBody !== null,
     }, reqBody instanceof Uint8Array ? reqBody : null);
 
+    function onAbort() {
+      try {
+        core.close(cancelHandleRid);
+      } catch (_) {
+        // might have already been closed
+      }
+      try {
+        core.close(requestBodyRid);
+      } catch (_) {
+        // might have already been closed
+      }
+    }
+    terminator[abortSignal.add](onAbort);
+
     if (requestBodyRid !== null) {
       if (reqBody === null || !(reqBody instanceof ReadableStream)) {
         throw new TypeError("Unreachable");
@@ -145,24 +196,49 @@
       const reader = reqBody.getReader();
       (async () => {
         while (true) {
-          const { value, done } = await reader.read();
+          const { value, done } = await reader.read().catch((err) => {
+            if (terminator.aborted) return { done: true, value: undefined };
+            throw err;
+          });
           if (done) break;
           if (!(value instanceof Uint8Array)) {
             await reader.cancel("value not a Uint8Array");
             break;
           }
           try {
-            await opFetchRequestWrite(requestBodyRid, value);
+            await opFetchRequestWrite(requestBodyRid, value).catch((err) => {
+              if (terminator.aborted) return;
+              throw err;
+            });
+            if (terminator.aborted) break;
           } catch (err) {
             await reader.cancel(err);
             break;
           }
         }
+        try {
           core.close(requestBodyRid);
+        } catch (_) {
+          // might have already been closed
+        }
       })();
     }
 
-    const resp = await opFetchSend(requestRid);
+    let resp;
+    try {
+      resp = await opFetchSend(requestRid).catch((err) => {
+        if (terminator.aborted) return;
+        throw err;
+      });
+    } finally {
+      try {
+        core.close(cancelHandleRid);
+      } catch (_) {
+        // might have already been closed
+      }
+    }
+    if (terminator.aborted) return abortedNetworkError();
+
     /** @type {InnerResponse} */
     const response = {
       headerList: resp.headers,
@@ -185,7 +261,7 @@
           );
         case "follow":
           core.close(resp.responseRid);
-          return httpRedirectFetch(req, response);
+          return httpRedirectFetch(req, response, terminator);
         case "manual":
           break;
       }
@@ -194,7 +270,9 @@
     if (nullBodyStatus(response.status)) {
       core.close(resp.responseRid);
     } else {
-      response.body = new InnerBody(createResponseBodyStream(resp.responseRid));
+      response.body = new InnerBody(
+        createResponseBodyStream(resp.responseRid, terminator),
+      );
     }
 
     if (recursive) return response;
@@ -211,7 +289,7 @@
    * @param {InnerResponse} response
    * @returns {Promise<InnerResponse>}
    */
-  function httpRedirectFetch(request, response) {
+  function httpRedirectFetch(request, response, terminator) {
     const locationHeaders = response.headerList.filter((entry) =>
       byteLowerCase(entry[0]) === "location"
     );
@@ -264,14 +342,16 @@
       request.body = res.body;
     }
     request.urlList.push(locationURL.href);
-    return mainFetch(request, true);
+    return mainFetch(request, true, terminator);
   }
 
   /**
    * @param {RequestInfo} input
    * @param {RequestInit} init
    */
-  async function fetch(input, init = {}) {
+  function fetch(input, init = {}) {
+    // 1.
+    const p = new Promise((resolve, reject) => {
       const prefix = "Failed to call 'fetch'";
       webidl.requiredArguments(arguments.length, 1, { prefix });
       input = webidl.converters["RequestInfo"](input, {
@@ -283,24 +363,69 @@
         context: "Argument 2",
       });
 
-    // 1.
-    const requestObject = new Request(input, init);
       // 2.
+      const requestObject = new Request(input, init);
+      // 3.
       const request = toInnerRequest(requestObject);
+      // 4.
+      if (requestObject.signal.aborted) {
+        reject(abortFetch(request, null));
+        return;
+      }
+
+      // 7.
+      let responseObject = null;
+      // 9.
+      let locallyAborted = false;
       // 10.
+      function onabort() {
+        locallyAborted = true;
+        reject(abortFetch(request, responseObject));
+      }
+      requestObject.signal[abortSignal.add](onabort);
+
       if (!requestObject.headers.has("Accept")) {
         request.headerList.push(["Accept", "*/*"]);
       }
 
       // 12.
-    const response = await mainFetch(request, false);
+      mainFetch(request, false, requestObject.signal).then((response) => {
+        // 12.1.
+        if (locallyAborted) return;
+        // 12.2.
+        if (response.aborted) {
+          reject(request, responseObject);
+          requestObject.signal[abortSignal.remove](onabort);
+          return;
+        }
+        // 12.3.
         if (response.type === "error") {
-      throw new TypeError(
+          const err = new TypeError(
             "Fetch failed: " + (response.error ?? "unknown error"),
           );
+          reject(err);
+          requestObject.signal[abortSignal.remove](onabort);
+          return;
+        }
+        responseObject = fromInnerResponse(response, "immutable");
+        resolve(responseObject);
+        requestObject.signal[abortSignal.remove](onabort);
+      }).catch((err) => {
+        reject(err);
+        requestObject.signal[abortSignal.remove](onabort);
+      });
+    });
+    return p;
   }
 
-    return fromInnerResponse(response, "immutable");
+  function abortFetch(request, responseObject) {
+    const error = new DOMException("Ongoing fetch was aborted.", "AbortError");
+    if (request.body !== null) request.body.cancel(error);
+    if (responseObject !== null) {
+      const response = toInnerResponse(responseObject);
+      if (response.body !== null) response.body.error(error);
+    }
+    return error;
   }
 
   window.__bootstrap.fetch ??= {};

extensions/fetch/internal.d.ts

@@ -82,6 +82,7 @@ declare namespace globalThis {
       function toInnerRequest(request: Request): InnerRequest;
       function fromInnerRequest(
         inner: InnerRequest,
+        signal: AbortSignal | null,
         guard:
           | "request"
           | "immutable"

extensions/fetch/lib.rs

@@ -16,6 +16,7 @@ use deno_core::AsyncRefCell;
 use deno_core::CancelFuture;
 use deno_core::CancelHandle;
 use deno_core::CancelTryFuture;
+use deno_core::Canceled;
 use deno_core::Extension;
 use deno_core::OpState;
 use deno_core::RcRef;
@@ -131,6 +132,7 @@ pub struct FetchArgs {
 pub struct FetchReturn {
   request_rid: ResourceId,
   request_body_rid: Option<ResourceId>,
+  cancel_handle_rid: Option<ResourceId>,
 }
 
 pub fn op_fetch<FP>(
@@ -157,7 +159,7 @@ where
 
   // Check scheme before asking for net permission
   let scheme = url.scheme();
-  let (request_rid, request_body_rid) = match scheme {
+  let (request_rid, request_body_rid, cancel_handle_rid) = match scheme {
     "http" | "https" => {
       let permissions = state.borrow_mut::<FP>();
       permissions.check_net_url(&url)?;
@@ -195,13 +197,19 @@ where
         request = request.header(name, v);
       }
 
-      let fut = request.send();
+      let cancel_handle = CancelHandle::new_rc();
+      let cancel_handle_ = cancel_handle.clone();
+
+      let fut = async move { request.send().or_cancel(cancel_handle_).await };
 
       let request_rid = state
         .resource_table
         .add(FetchRequestResource(Box::pin(fut)));
 
-      (request_rid, request_body_rid)
+      let cancel_handle_rid =
+        state.resource_table.add(FetchCancelHandle(cancel_handle));
+
+      (request_rid, request_body_rid, Some(cancel_handle_rid))
     }
     "data" => {
       let data_url = DataUrl::process(url.as_str())
@@ -216,13 +224,13 @@ where
         .header(http::header::CONTENT_TYPE, data_url.mime_type().to_string())
         .body(reqwest::Body::from(body))?;
 
-      let fut = async move { Ok(Response::from(response)) };
+      let fut = async move { Ok(Ok(Response::from(response))) };
 
       let request_rid = state
         .resource_table
         .add(FetchRequestResource(Box::pin(fut)));
 
-      (request_rid, None)
+      (request_rid, None, None)
     }
     "blob" => {
       let blob_url_storage =
@@ -244,13 +252,13 @@ where
         .header(http::header::CONTENT_TYPE, blob.media_type)
         .body(reqwest::Body::from(blob.data))?;
 
-      let fut = async move { Ok(Response::from(response)) };
+      let fut = async move { Ok(Ok(Response::from(response))) };
 
       let request_rid = state
         .resource_table
         .add(FetchRequestResource(Box::pin(fut)));
 
-      (request_rid, None)
+      (request_rid, None, None)
     }
     _ => return Err(type_error(format!("scheme '{}' not supported", scheme))),
   };
@@ -258,6 +266,7 @@ where
   Ok(FetchReturn {
     request_rid,
     request_body_rid,
+    cancel_handle_rid,
   })
 }
 
@@ -287,8 +296,9 @@ pub async fn op_fetch_send(
     .expect("multiple op_fetch_send ongoing");
 
   let res = match request.0.await {
-    Ok(res) => res,
-    Err(e) => return Err(type_error(e.to_string())),
+    Ok(Ok(res)) => res,
+    Ok(Err(err)) => return Err(type_error(err.to_string())),
+    Err(_) => return Err(type_error("request was cancelled")),
   };
 
   //debug!("Fetch response {}", url);
@@ -372,8 +382,11 @@ pub async fn op_fetch_response_read(
   Ok(read)
 }
 
+type CancelableResponseResult =
+  Result<Result<Response, reqwest::Error>, Canceled>;
+
 struct FetchRequestResource(
-  Pin<Box<dyn Future<Output = Result<Response, reqwest::Error>>>>,
+  Pin<Box<dyn Future<Output = CancelableResponseResult>>>,
 );
 
 impl Resource for FetchRequestResource {
@@ -382,6 +395,18 @@ impl Resource for FetchRequestResource {
   }
 }
 
+struct FetchCancelHandle(Rc<CancelHandle>);
+
+impl Resource for FetchCancelHandle {
+  fn name(&self) -> Cow<str> {
+    "fetchCancelHandle".into()
+  }
+
+  fn close(self: Rc<Self>) {
+    self.0.cancel()
+  }
+}
+
 struct FetchRequestBodyResource {
   body: AsyncRefCell<mpsc::Sender<std::io::Result<Vec<u8>>>>,
   cancel: CancelHandle,
@@ -391,6 +416,10 @@ impl Resource for FetchRequestBodyResource {
   fn name(&self) -> Cow<str> {
     "fetchRequestBody".into()
   }
+
+  fn close(self: Rc<Self>) {
+    self.cancel.cancel()
+  }
 }
 
 type BytesStream =
@@ -405,6 +434,10 @@ impl Resource for FetchResponseBodyResource {
   fn name(&self) -> Cow<str> {
     "fetchResponseBody".into()
   }
+
+  fn close(self: Rc<Self>) {
+    self.cancel.cancel()
+  }
 }
 
 struct HttpClientResource {

extensions/web/03_abort_signal.js

@@ -118,11 +118,25 @@
     AbortSignal,
   );
 
+  function newSignal() {
+    return new AbortSignal(illegalConstructorKey);
+  }
+
+  function follow(followingSignal, parentSignal) {
+    if (parentSignal.aborted) {
+      followingSignal[signalAbort]();
+    } else {
+      parentSignal[add](() => followingSignal[signalAbort]());
+    }
+  }
+
   window.AbortSignal = AbortSignal;
   window.AbortController = AbortController;
   window.__bootstrap.abortSignal = {
     add,
     signalAbort,
     remove,
+    follow,
+    newSignal,
   };
 })(this);

runtime/js/40_http.js

@@ -72,7 +72,7 @@
         headersList,
         body !== null ? new InnerBody(body) : null,
       );
-      const request = fromInnerRequest(innerRequest, "immutable");
+      const request = fromInnerRequest(innerRequest, null, "immutable");
 
       const respondWith = createRespondWith(this, responseSenderRid);
 

tools/wpt/expectation.json

@@ -1052,7 +1052,6 @@
         "Request interface: attribute keepalive",
         "Request interface: attribute isReloadNavigation",
         "Request interface: attribute isHistoryNavigation",
-        "Request interface: attribute signal",
         "Request interface: attribute body",
         "Request interface: attribute bodyUsed",
         "Request interface: new Request('about:blank') must inherit property \"destination\" with the proper type",
@@ -1065,14 +1064,22 @@
         "Request interface: new Request('about:blank') must inherit property \"keepalive\" with the proper type",
         "Request interface: new Request('about:blank') must inherit property \"isReloadNavigation\" with the proper type",
         "Request interface: new Request('about:blank') must inherit property \"isHistoryNavigation\" with the proper type",
-        "Request interface: new Request('about:blank') must inherit property \"signal\" with the proper type",
         "Response interface: operation error()",
         "Response interface: operation redirect(USVString, optional unsigned short)",
         "Response interface: attribute body",
         "Response interface: attribute bodyUsed",
         "Response interface: calling redirect(USVString, optional unsigned short) on new Response() with too few arguments must throw TypeError",
         "Window interface: operation fetch(RequestInfo, optional RequestInit)"
+      ],
+      "abort": {
+        "general.any.html": [
+          "response.arrayBuffer() rejects if already aborted",
+          "response.blob() rejects if already aborted",
+          "response.formData() rejects if already aborted",
+          "response.json() rejects if already aborted",
+          "response.text() rejects if already aborted"
         ]
+      }
     },
     "data-urls": {
       "base64.any.html": true,