Add stream timeout for attachment downloads

ts/util/getStreamWithTimeout.ts

@@ -0,0 +1,62 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import type { Readable } from 'stream';
+
+import * as Bytes from '../Bytes';
+import { explodePromise } from './explodePromise';
+
+export type OptionsType = Readonly<{
+  name: string;
+  timeout: number;
+  abortController: { abort(): void };
+}>;
+
+export class StreamTimeoutError extends Error {}
+
+export function getStreamWithTimeout(
+  stream: Readable,
+  { name, timeout, abortController }: OptionsType
+): Promise<Uint8Array> {
+  const { promise, resolve, reject } = explodePromise<Uint8Array>();
+
+  const chunks = new Array<Uint8Array>();
+
+  let timer: NodeJS.Timeout | undefined;
+
+  const clearTimer = () => {
+    if (timer !== undefined) {
+      clearTimeout(timer);
+      timer = undefined;
+    }
+  };
+
+  const reset = () => {
+    clearTimer();
+
+    timer = setTimeout(() => {
+      abortController.abort();
+      reject(new StreamTimeoutError(`getStreamWithTimeout(${name}) timed out`));
+    }, timeout);
+  };
+
+  stream.on('data', chunk => {
+    reset();
+
+    chunks.push(chunk);
+  });
+
+  stream.on('end', () => {
+    clearTimer();
+    resolve(Bytes.concatenate(chunks));
+  });
+
+  stream.on('error', error => {
+    clearTimer();
+    reject(error);
+  });
+
+  reset();
+
+  return promise;
+}