feat: add abort reason support (#1686)

* feat: add abort reason support

* fix: set default error for node v16

* fix: jest test on v16.8

* add tests

* lint

lib/fetch/index.js

@@ -84,16 +84,30 @@ class Fetch extends EE {
     this.emit('terminated', reason)
   }
 
-  abort () {
+  // https://fetch.spec.whatwg.org/#fetch-controller-abort
+  abort (error) {
     if (this.state !== 'ongoing') {
       return
     }
 
-    const reason = new DOMException('The operation was aborted.', 'AbortError')
-
+    // 1. Set controller’s state to "aborted".
     this.state = 'aborted'
-    this.connection?.destroy(reason)
-    this.emit('terminated', reason)
+
+    // 2. Let fallbackError be an "AbortError" DOMException.
+    // 3. Set error to fallbackError if it is not given.
+    if (!error) {
+      error = new DOMException('The operation was aborted.', 'AbortError')
+    }
+
+    // 4. Let serializedError be StructuredSerialize(error).
+    //    If that threw an exception, catch it, and let
+    //    serializedError be StructuredSerialize(fallbackError).
+
+    // 5. Set controller’s serialized abort reason to serializedError.
+    this.serializedAbortReason = error
+
+    this.connection?.destroy(error)
+    this.emit('terminated', error)
   }
 }
 
@@ -125,8 +139,9 @@ async function fetch (input, init = {}) {
 
   // 4. If requestObject’s signal’s aborted flag is set, then:
   if (requestObject.signal.aborted) {
-    // 1. Abort fetch with p, request, and null.
-    abortFetch(p, request, null)
+    // 1. Abort the fetch() call with p, request, null, and
+    //    requestObject’s signal’s abort reason.
+    abortFetch(p, request, null, requestObject.signal.reason)
 
     // 2. Return p.
     return p.promise
@@ -160,8 +175,9 @@ async function fetch (input, init = {}) {
       // 1. Set locallyAborted to true.
       locallyAborted = true
 
-      // 2. Abort fetch with p, request, and responseObject.
-      abortFetch(p, request, responseObject)
+      // 2. Abort the fetch() call with p, request, responseObject,
+      //    and requestObject’s signal’s abort reason.
+      abortFetch(p, request, responseObject, requestObject.signal.reason)
 
       // 3. If controller is not null, then abort controller.
       if (controller != null) {
@@ -186,10 +202,16 @@ async function fetch (input, init = {}) {
       return
     }
 
-    // 2. If response’s aborted flag is set, then abort fetch with p,
-    // request, and responseObject, and terminate these substeps.
+    // 2. If response’s aborted flag is set, then:
     if (response.aborted) {
-      abortFetch(p, request, responseObject)
+      // 1. Let deserializedError be the result of deserialize a serialized
+      //    abort reason given controller’s serialized abort reason and
+      //    relevantRealm.
+
+      // 2. Abort the fetch() call with p, request, responseObject, and
+      //    deserializedError.
+
+      abortFetch(p, request, responseObject, controller.serializedAbortReason)
       return
     }
 
@@ -297,14 +319,18 @@ function markResourceTiming (timingInfo, originalURL, initiatorType, globalThis,
 }
 
 // https://fetch.spec.whatwg.org/#abort-fetch
-function abortFetch (p, request, responseObject) {
-  // 1. Let error be an "AbortError" DOMException.
-  const error = new DOMException('The operation was aborted.', 'AbortError')
+function abortFetch (p, request, responseObject, error) {
+  // Note: AbortSignal.reason was added in node v17.2.0
+  // which would give us an undefined error to reject with.
+  // Remove this once node v16 is no longer supported.
+  if (!error) {
+    error = new DOMException('The operation was aborted.', 'AbortError')
+  }
 
-  // 2. Reject promise with error.
+  // 1. Reject promise with error.
   p.reject(error)
 
-  // 3. If request’s body is not null and is readable, then cancel request’s
+  // 2. If request’s body is not null and is readable, then cancel request’s
   // body with error.
   if (request.body != null && isReadable(request.body?.stream)) {
     request.body.stream.cancel(error).catch((err) => {
@@ -316,15 +342,15 @@ function abortFetch (p, request, responseObject) {
     })
   }
 
-  // 4. If responseObject is null, then return.
+  // 3. If responseObject is null, then return.
   if (responseObject == null) {
     return
   }
 
-  // 5. Let response be responseObject’s response.
+  // 4. Let response be responseObject’s response.
   const response = responseObject[kState]
 
-  // 6. If response’s body is not null and is readable, then error response’s
+  // 5. If response’s body is not null and is readable, then error response’s
   // body with error.
   if (response.body != null && isReadable(response.body?.stream)) {
     response.body.stream.cancel(error).catch((err) => {
@@ -1720,9 +1746,9 @@ async function httpNetworkFetch (
   }
 
   // 12. Let cancelAlgorithm be an algorithm that aborts fetchParams’s
-  // controller.
-  const cancelAlgorithm = () => {
-    fetchParams.controller.abort()
+  // controller with reason, given reason.
+  const cancelAlgorithm = (reason) => {
+    fetchParams.controller.abort(reason)
   }
 
   // 13. Let highWaterMark be a non-negative, non-NaN number, chosen by
@@ -1862,10 +1888,13 @@ async function httpNetworkFetch (
       // 1. Set response’s aborted flag.
       response.aborted = true
 
-      // 2. If stream is readable, error stream with an "AbortError" DOMException.
+      // 2. If stream is readable, then error stream with the result of
+      //    deserialize a serialized abort reason given fetchParams’s
+      //    controller’s serialized abort reason and an
+      //    implementation-defined realm.
       if (isReadable(stream)) {
         fetchParams.controller.controller.error(
-          new DOMException('The operation was aborted.', 'AbortError')
+          fetchParams.controller.serializedAbortReason
         )
       }
     } else {

test/fetch/abort.js

@@ -88,3 +88,39 @@ test('Allow the usage of custom implementation of AbortController', async (t) =>
     t.equal(e.code, DOMException.ABORT_ERR)
   }
 })
+
+test('allows aborting with custom errors', { skip: process.version.startsWith('v16.') }, async (t) => {
+  const server = createServer((req, res) => {
+    setTimeout(() => res.end(), 5000)
+  }).listen(0)
+
+  t.teardown(server.close.bind(server))
+  await once(server, 'listening')
+
+  t.test('Using AbortSignal.timeout', async (t) => {
+    await t.rejects(
+      fetch(`http://localhost:${server.address().port}`, {
+        signal: AbortSignal.timeout(50)
+      }),
+      {
+        name: 'TimeoutError',
+        code: DOMException.TIMEOUT_ERR
+      }
+    )
+  })
+
+  t.test('Error defaults to an AbortError DOMException', async (t) => {
+    const ac = new AbortController()
+    ac.abort() // no reason
+
+    await t.rejects(
+      fetch(`http://localhost:${server.address().port}`, {
+        signal: ac.signal
+      }),
+      {
+        name: 'AbortError',
+        code: DOMException.ABORT_ERR
+      }
+    )
+  })
+})

test/jest/instanceof-error.test.js

@@ -37,7 +37,7 @@ runIf(nodeMajor >= 16)('Real use-case', async () => {
     signal: ac.signal
   })
 
-  await expect(promise).rejects.toThrowError('The operation was aborted.')
+  await expect(promise).rejects.toThrowError(/^Th(e|is) operation was aborted\.?$/)
 
   server.close()
   await once(server, 'close')

test/wpt/tests/fetch/api/abort/general.any.js

@@ -6,6 +6,9 @@
 
 const BODY_METHODS = ['arrayBuffer', 'blob', 'formData', 'json', 'text'];
 
+const error1 = new Error('error1');
+error1.name = 'error1';
+
 // This is used to close connections that weren't correctly closed during the tests,
 // otherwise you can end up running out of HTTP connections.
 let requestAbortKeys = [];
@@ -31,6 +34,16 @@ promise_test(async t => {
   await promise_rejects_dom(t, "AbortError", fetchPromise);
 }, "Aborting rejects with AbortError");
 
+promise_test(async t => {
+  const controller = new AbortController();
+  const signal = controller.signal;
+  controller.abort(error1);
+
+  const fetchPromise = fetch('../resources/data.json', { signal });
+
+  await promise_rejects_exactly(t, error1, fetchPromise, 'fetch() should reject with abort reason');
+}, "Aborting rejects with abort reason");
+
 promise_test(async t => {
   const controller = new AbortController();
   const signal = controller.signal;
@@ -91,6 +104,22 @@ promise_test(async t => {
   await promise_rejects_dom(t, "AbortError", fetchPromise);
 }, "Signal on request object");
 
+promise_test(async t => {
+  const controller = new AbortController();
+  const signal = controller.signal;
+  controller.abort(error1);
+
+  const request = new Request('../resources/data.json', { signal });
+
+  assert_not_equals(request.signal, signal, 'Request has a new signal, not a reference');
+  assert_true(request.signal.aborted, `Request's signal has aborted`);
+  assert_equals(request.signal.reason, error1, `Request's signal's abort reason is error1`);
+
+  const fetchPromise = fetch(request);
+
+  await promise_rejects_exactly(t, error1, fetchPromise, "fetch() should reject with abort reason");
+}, "Signal on request object should also have abort reason");
+
 promise_test(async t => {
   const controller = new AbortController();
   const signal = controller.signal;