Always create abortController for each execution, listen to external (passed in by client) abort signal and abort our own signal after the execution is ended. Polyfill AbortController

Author: igor.luckenkov

src/execution/__tests__/executor-test.ts

@@ -4,6 +4,7 @@ import { describe, it } from 'mocha';
 import { expectJSON } from '../../__testUtils__/expectJSON.js';
 import { resolveOnNextTick } from '../../__testUtils__/resolveOnNextTick.js';
 
+import { AbortController } from '../../jsutils/AbortController.js';
 import { inspect } from '../../jsutils/inspect.js';
 
 import { Kind } from '../../language/kinds.js';
@@ -1314,59 +1315,59 @@ describe('Execute: Handles basic execution tasks', () => {
     expect(possibleTypes).to.deep.equal([fooObject]);
   });
 
-  describe('Abort execution', () => {
-    it('stops execution and throws an error when signal is aborted', async () => {
-      /**
-       * This test has 3 resolvers nested in each other.
-       * Every resolve function waits 200ms before returning data.
-       *
-       * The test waits for the first resolver and half of the 2nd resolver execution time (200ms + 100ms)
-       * and then aborts the execution.
-       *
-       * 2nd resolver execution finishes, and we then expect to not execute the 3rd resolver
-       * and to get an error about aborted operation.
-       */
-
-      const WAIT_MS_BEFORE_RESOLVING = 200;
-      const ABORT_IN_MS_AFTER_STARTING_EXECUTION =
-        WAIT_MS_BEFORE_RESOLVING + WAIT_MS_BEFORE_RESOLVING / 2;
-
-      const schema = new GraphQLSchema({
-        query: new GraphQLObjectType({
-          name: 'Query',
-          fields: {
-            resolvesIn500ms: {
-              type: new GraphQLObjectType({
-                name: 'ResolvesIn500ms',
-                fields: {
-                  resolvesIn400ms: {
-                    type: new GraphQLObjectType({
-                      name: 'ResolvesIn400ms',
-                      fields: {
-                        shouldNotBeResolved: {
-                          type: GraphQLString,
-                          resolve: () => {
-                            throw new Error('This should not be executed!');
-                          },
+  it('stops execution and throws an error when signal is aborted', async () => {
+    /**
+     * This test has 3 resolvers nested in each other.
+     * Every resolve function waits 200ms before returning data.
+     *
+     * The test waits for the first resolver and half of the 2nd resolver execution time (200ms + 100ms)
+     * and then aborts the execution.
+     *
+     * 2nd resolver execution finishes, and we then expect to not execute the 3rd resolver
+     * and to get an error about aborted operation.
+     */
+
+    const WAIT_MS_BEFORE_RESOLVING = 200;
+    const ABORT_IN_MS_AFTER_STARTING_EXECUTION =
+      WAIT_MS_BEFORE_RESOLVING + WAIT_MS_BEFORE_RESOLVING / 2;
+
+    const schema = new GraphQLSchema({
+      query: new GraphQLObjectType({
+        name: 'Query',
+        fields: {
+          resolvesIn500ms: {
+            type: new GraphQLObjectType({
+              name: 'ResolvesIn500ms',
+              fields: {
+                resolvesIn400ms: {
+                  type: new GraphQLObjectType({
+                    name: 'ResolvesIn400ms',
+                    fields: {
+                      shouldNotBeResolved: {
+                        type: GraphQLString,
+                        /* c8 ignore next 3 */
+                        resolve: () => {
+                          throw new Error('This should not be executed!');
                         },
                       },
+                    },
+                  }),
+                  resolve: () =>
+                    new Promise((resolve) => {
+                      setTimeout(() => resolve({}), WAIT_MS_BEFORE_RESOLVING);
                     }),
-                    resolve: () =>
-                      new Promise((resolve) => {
-                        setTimeout(() => resolve({}), WAIT_MS_BEFORE_RESOLVING);
-                      }),
-                  },
                 },
+              },
+            }),
+            resolve: () =>
+              new Promise((resolve) => {
+                setTimeout(() => resolve({}), WAIT_MS_BEFORE_RESOLVING);
               }),
-              resolve: () =>
-                new Promise((resolve) => {
-                  setTimeout(() => resolve({}), WAIT_MS_BEFORE_RESOLVING);
-                }),
-            },
           },
-        }),
-      });
-      const document = parse(`
+        },
+      }),
+    });
+    const document = parse(`
       query {
         resolvesIn500ms {
           resolvesIn400ms {
@@ -1376,67 +1377,22 @@ describe('Execute: Handles basic execution tasks', () => {
       }
     `);
 
-      const abortController = new AbortController();
-      const executionPromise = execute({
-        schema,
-        document,
-        signal: abortController.signal,
-      });
-
-      setTimeout(
-        () => abortController.abort(),
-        ABORT_IN_MS_AFTER_STARTING_EXECUTION,
-      );
-
-      const result = await executionPromise;
-      expect(result.errors?.[0].message).to.eq(
-        'Execution aborted. Reason: AbortError: This operation was aborted',
-      );
-      expect(result.data).to.eql({
-        resolvesIn500ms: { resolvesIn400ms: null },
-      });
-    });
-
-    const abortMessageTestInputs = [
-      { message: 'Aborted from somewhere', reason: 'Aborted from somewhere' },
-      { message: undefined, reason: 'AbortError: This operation was aborted' },
-    ];
-
-    for (const { message, reason } of abortMessageTestInputs) {
-      it('aborts with "Reason:" in the error message', async () => {
-        const schema = new GraphQLSchema({
-          query: new GraphQLObjectType({
-            name: 'Query',
-            fields: {
-              a: {
-                type: GraphQLString,
-                resolve: () =>
-                  new Promise((resolve) => {
-                    setTimeout(() => resolve({}), 100);
-                  }),
-              },
-            },
-          }),
-        });
-
-        const document = parse(`
-        query { a }
-      `);
-
-        const abortController = new AbortController();
-        const executionPromise = execute({
-          schema,
-          document,
-          signal: abortController.signal,
-        });
+    const abortController = new AbortController();
+    const executionPromise = execute({
+      schema,
+      document,
+      signal: abortController.signal,
+    });
 
-        abortController.abort(message);
+    setTimeout(
+      () => abortController.abort(),
+      ABORT_IN_MS_AFTER_STARTING_EXECUTION,
+    );
 
-        const { errors } = await executionPromise;
-        expect(errors?.[0].message).to.eq(
-          `Execution aborted. Reason: ${reason}`,
-        );
-      });
-    }
+    const result = await executionPromise;
+    expect(result.errors?.[0].message).to.eq('Execution aborted.');
+    expect(result.data).to.eql({
+      resolvesIn500ms: { resolvesIn400ms: null },
+    });
   });
 });

src/execution/execute.ts

@@ -1,3 +1,8 @@
+import type {
+  IAbortController,
+  IAbortSignal,
+} from '../jsutils/AbortController.js';
+import { AbortController } from '../jsutils/AbortController.js';
 import { inspect } from '../jsutils/inspect.js';
 import { invariant } from '../jsutils/invariant.js';
 import { isAsyncIterable } from '../jsutils/isAsyncIterable.js';
@@ -122,9 +127,10 @@ export interface ExecutionContext {
   subscribeFieldResolver: GraphQLFieldResolver<any, any>;
   errors: Array<GraphQLError>;
   subsequentPayloads: Set<AsyncPayloadRecord>;
-  signal: Maybe<{
-    isAborted: boolean;
-    instance: AbortSignal;
+  abortion: Maybe<{
+    passedInAbortSignal: IAbortSignal;
+    executionAbortController: IAbortController;
+    executionAbortSignal: IAbortSignal;
   }>;
 }
 
@@ -265,7 +271,7 @@ export interface ExecutionArgs {
   fieldResolver?: Maybe<GraphQLFieldResolver<any, any>>;
   typeResolver?: Maybe<GraphQLTypeResolver<any, any>>;
   subscribeFieldResolver?: Maybe<GraphQLFieldResolver<any, any>>;
-  signal?: AbortSignal;
+  signal?: IAbortSignal;
 }
 
 const UNEXPECTED_EXPERIMENTAL_DIRECTIVES =
@@ -342,28 +348,25 @@ export function experimentalExecuteIncrementally(
   return executeImpl(exeContext);
 }
 
-function subscribeToAbortSignal(exeContext: ExecutionContext): {
-  unsubscribeFromAbortSignal: () => void;
-} {
-  const onAbort = () => {
-    if ('signal' in exeContext && exeContext.signal) {
-      exeContext.signal.isAborted = true;
-    }
-  };
+function subscribeToAbortSignal(exeContext: ExecutionContext): () => void {
+  const { abortion } = exeContext;
+  if (!abortion) {
+    return () => null;
+  }
 
-  exeContext.signal?.instance.addEventListener('abort', onAbort);
+  const onAbort = () => abortion.executionAbortController.abort(abortion);
+  abortion.passedInAbortSignal.addEventListener('abort', onAbort);
 
-  return {
-    unsubscribeFromAbortSignal: () => {
-      exeContext.signal?.instance.removeEventListener('abort', onAbort);
-    },
+  return () => {
+    abortion.passedInAbortSignal.removeEventListener('abort', onAbort);
+    abortion.executionAbortController.abort();
   };
 }
 
 function executeImpl(
   exeContext: ExecutionContext,
 ): PromiseOrValue<ExecutionResult | ExperimentalIncrementalExecutionResults> {
-  const { unsubscribeFromAbortSignal } = subscribeToAbortSignal(exeContext);
+  const unsubscribeFromAbortSignal = subscribeToAbortSignal(exeContext);
 
   // Return a Promise that will eventually resolve to the data described by
   // The "Response" section of the GraphQL specification.
@@ -473,7 +476,7 @@ export function buildExecutionContext(
     fieldResolver,
     typeResolver,
     subscribeFieldResolver,
-    signal,
+    signal: passedInAbortSignal,
   } = args;
 
   // If the schema used for execution is invalid, throw an error.
@@ -539,7 +542,23 @@ export function buildExecutionContext(
     subscribeFieldResolver: subscribeFieldResolver ?? defaultFieldResolver,
     subsequentPayloads: new Set(),
     errors: [],
-    signal: signal ? { instance: signal, isAborted: false } : null,
+    abortion: getContextAbortionEntities(passedInAbortSignal),
+  };
+}
+
+function getContextAbortionEntities(
+  passedInAbortSignal: Maybe<IAbortSignal>,
+): ExecutionContext['abortion'] {
+  if (!passedInAbortSignal) {
+    return null;
+  }
+
+  const executionAbortController = new AbortController();
+
+  return {
+    passedInAbortSignal,
+    executionAbortController,
+    executionAbortSignal: executionAbortController.signal,
   };
 }
 
@@ -873,12 +892,8 @@ function completeValue(
   result: unknown,
   asyncPayloadRecord?: AsyncPayloadRecord,
 ): PromiseOrValue<unknown> {
-  if (exeContext.signal?.isAborted) {
-    throw new GraphQLError(
-      `Execution aborted. Reason: ${
-        exeContext.signal.instance.reason ?? 'Unknown.'
-      }`,
-    );
+  if (exeContext.abortion?.executionAbortSignal.aborted) {
+    throw new GraphQLError('Execution aborted.');
   }
 
   // If result is an Error, throw a located error.

src/jsutils/AbortController.ts

@@ -0,0 +1,31 @@
+export interface IAbortSignal {
+  aborted: boolean;
+  addEventListener: (type: string, handler: () => void) => void;
+  removeEventListener: (type: string, handler: () => void) => void;
+}
+
+export interface IAbortController {
+  signal: IAbortSignal;
+  abort: (reason?: any) => void;
+}
+
+/* c8 ignore start */
+export const AbortController: new () => IAbortController =
+  // eslint-disable-next-line no-undef
+  global.AbortController ||
+  class MockAbortController implements IAbortController {
+    private _signal: IAbortSignal = {
+      aborted: false,
+      addEventListener: () => null,
+      removeEventListener: () => null,
+    };
+
+    public get signal(): IAbortSignal {
+      return this._signal;
+    }
+
+    public abort(): void {
+      this._signal.aborted = true;
+    }
+  };
+/* c8 ignore stop */