Add ability to cancel in-progress requests (#287)

index.js

@@ -17,6 +17,7 @@ const createErrorClass = require('create-error-class');
 const isRetryAllowed = require('is-retry-allowed');
 const Buffer = require('safe-buffer').Buffer;
 const isPlainObj = require('is-plain-obj');
+const PCancelable = require('p-cancelable');
 const pkg = require('./package');
 
 function requestAsEventEmitter(opts) {
@@ -100,10 +101,23 @@ function requestAsEventEmitter(opts) {
 }
 
 function asPromise(opts) {
-	return new Promise((resolve, reject) => {
+	return new PCancelable((onCancel, resolve, reject) => {
 		const ee = requestAsEventEmitter(opts);
+		let cancelOnRequest = false;
+
+		onCancel(() => {
+			cancelOnRequest = true;
+		});
 
 		ee.on('request', req => {
+			if (cancelOnRequest) {
+				req.abort();
+			}
+
+			onCancel(() => {
+				req.abort();
+			});
+
 			if (isStream(opts.body)) {
 				opts.body.pipe(req);
 				opts.body = undefined;

package.json

@@ -56,6 +56,7 @@
     "is-retry-allowed": "^1.0.0",
     "is-stream": "^1.0.0",
     "lowercase-keys": "^1.0.0",
+    "p-cancelable": "^0.2.0",
     "safe-buffer": "^5.0.1",
     "timed-out": "^4.0.0",
     "url-parse-lax": "^1.0.0"

readme.md

@@ -12,7 +12,7 @@
 
 A nicer interface to the built-in [`http`](http://nodejs.org/api/http.html) module.
 
-It supports following redirects, promises, streams, retries, automagically handling gzip/deflate and some convenience options.
+It supports following redirects, promises, streams, retries, automagically handling gzip/deflate, canceling of requests, and some convenience options.
 
 Created because [`request`](https://github.com/request/request) is bloated *(several megabytes!)*.
 
@@ -218,6 +218,11 @@ When server redirects you more than 10 times. Includes a `redirectUrls` property
 When given an unsupported protocol.
 
 
+## Aborting the request
+
+The promise returned by Got has a `.cancel()` function which, when called, aborts the request.
+
+
 ## Proxies
 
 You can use the [`tunnel`](https://github.com/koichik/node-tunnel) module with the `agent` option to work with proxies:

test/cancel.js

@@ -0,0 +1,68 @@
+import stream from 'stream';
+import test from 'ava';
+import getStream from 'get-stream';
+import PCancelable from 'p-cancelable';
+import got from '../';
+import {createServer} from './helpers/server';
+
+const Readable = stream.Readable;
+
+async function createAbortServer() {
+	const s = await createServer();
+	const aborted = new Promise((resolve, reject) => {
+		s.on('/abort', (req, res) => {
+			req.on('aborted', resolve);
+			res.on('finish', reject.bind(null, new Error('Request finished instead of aborting.')));
+
+			getStream(req).then(() => {
+				res.end();
+			});
+		});
+	});
+
+	await s.listen(s.port);
+
+	return {
+		aborted,
+		url: `${s.url}/abort`
+	};
+}
+
+test('cancel in-progress request', async t => {
+	const helper = await createAbortServer();
+	const body = new Readable({
+		read() {}
+	});
+	body.push('1');
+
+	const p = got(helper.url, {body});
+
+	// Wait for the stream to be established before canceling
+	setTimeout(() => {
+		p.cancel();
+		body.push(null);
+	}, 100);
+
+	await t.throws(p, PCancelable.CancelError);
+	await t.notThrows(helper.aborted, 'Request finished instead of aborting.');
+});
+
+test('cancel immediately', async t => {
+	const s = await createServer();
+	const aborted = new Promise((resolve, reject) => {
+    // We won't get an abort or even a connection
+    // We assume no request within 1000ms equals a (client side) aborted request
+		s.on('/abort', (req, res) => {
+			res.on('finish', reject.bind(this, new Error('Request finished instead of aborting.')));
+			res.end();
+		});
+		setTimeout(resolve, 1000);
+	});
+
+	await s.listen(s.port);
+
+	const p = got(`${s.url}/abort`);
+	p.cancel();
+	await t.throws(p);
+	await t.notThrows(aborted, 'Request finished instead of aborting.');
+});