http2-wrapper

What is http2-wrapper?

The http2-wrapper npm package is a module that provides an easy-to-use wrapper around the native HTTP/2 client and server capabilities in Node.js. It simplifies the process of making HTTP/2 requests and handling responses, as well as creating HTTP/2 servers.

What are http2-wrapper's main functionalities?

Making HTTP/2 requests

This feature allows you to make HTTP/2 requests to a server. The code sample demonstrates how to perform a simple GET request using the http2-wrapper.

const http2wrapper = require('http2-wrapper');

const options = {
  hostname: 'example.com',
  protocol: 'https:',
  path: '/',
  method: 'GET'
};

http2wrapper.request(options, (res) => {
  console.log(`Status Code: ${res.statusCode}`);

  res.on('data', (chunk) => {
    console.log(chunk);
  });
}).end();

Creating HTTP/2 servers

This feature allows you to create an HTTP/2 server. The code sample shows how to set up a simple HTTP/2 server that responds with 'Hello World' to all requests.

const http2wrapper = require('http2-wrapper');
const http2 = require('http2');

const server = http2.createSecureServer({
  key: fs.readFileSync('server-key.pem'),
  cert: fs.readFileSync('server-cert.pem')
});

server.on('stream', (stream, headers) => {
  stream.respond({
    'content-type': 'text/html',
    ':status': 200
  });
  stream.end('<h1>Hello World</h1>');
});

http2wrapper.createServer(server).listen(8443);

Other packages similar to http2-wrapper

spdy

The 'spdy' package is an HTTP/2 and SPDY protocol client and server implementation for Node.js. It provides similar functionalities to http2-wrapper but also includes support for SPDY, which is a now-deprecated protocol that was a precursor to HTTP/2.

node-fetch

While 'node-fetch' is primarily a light-weight module that brings window.fetch to Node.js, it can be used to make HTTP/2 requests when combined with the built-in http2 module in Node.js. It does not provide server capabilities like http2-wrapper.

README

http2-wrapper

HTTP/2 client, just with the familiar https API

This package was created to support HTTP/2 without the need to rewrite your code.
I recommend adapting to the http2 module if possible - it's much simpler to use and has many cool features!

Tip: http2-wrapper is very useful when you rely on other modules that use the HTTP/1 API and you want to support HTTP/2.

Pro Tip: While the native http2 doesn't have agents yet, you can use http2-wrapper Agents and still operate on the native HTTP/2 streams.

Installation

$ npm install http2-wrapper
$ yarn add http2-wrapper

Usage

const http2 = require('http2-wrapper');

const options = {
	hostname: 'nghttp2.org',
	protocol: 'https:',
	path: '/httpbin/post',
	method: 'POST',
	headers: {
		'content-length': 6
	}
};

const request = http2.request(options, response => {
	console.log('statusCode:', response.statusCode);
	console.log('headers:', response.headers);

	const body = [];
	response.on('data', chunk => {
		body.push(chunk);
	});
	response.on('end', () => {
		console.log('body:', Buffer.concat(body).toString());
	});
});

request.on('error', console.error);

request.write('123');
request.end('456');

// statusCode: 200
// headers: [Object: null prototype] {
//   ':status': 200,
//   date: 'Fri, 27 Sep 2019 19:45:46 GMT',
//   'content-type': 'application/json',
//   'access-control-allow-origin': '*',
//   'access-control-allow-credentials': 'true',
//   'content-length': '239',
//   'x-backend-header-rtt': '0.002516',
//   'strict-transport-security': 'max-age=31536000',
//   server: 'nghttpx',
//   via: '1.1 nghttpx',
//   'alt-svc': 'h3-23=":4433"; ma=3600',
//   'x-frame-options': 'SAMEORIGIN',
//   'x-xss-protection': '1; mode=block',
//   'x-content-type-options': 'nosniff'
// }
// body: {
//   "args": {},
//   "data": "123456",
//   "files": {},
//   "form": {},
//   "headers": {
//     "Content-Length": "6",
//     "Host": "nghttp2.org"
//   },
//   "json": 123456,
//   "origin": "xxx.xxx.xxx.xxx",
//   "url": "https://nghttp2.org/httpbin/post"
// }

API

Note: The session option was renamed to tlsSession for better readability.

Note: The timeout option applies to HTTP/2 streams only. In order to set session timeout, pass an Agent with custom timeout option set.

http2.auto(url, options, callback)

Performs ALPN negotiation. Returns a Promise giving proper ClientRequest instance (depending on the ALPN).

Note: The agent option represents an object with http, https and http2 properties.

const http2 = require('http2-wrapper');

const options = {
	hostname: 'httpbin.org',
	protocol: 'http:', // Try changing this to https:
	path: '/post',
	method: 'POST',
	headers: {
		'content-length': 6
	}
};

(async () => {
	try {
		const request = await http2.auto(options, response => {
			console.log('statusCode:', response.statusCode);
			console.log('headers:', response.headers);

			const body = [];
			response.on('data', chunk => body.push(chunk));
			response.on('end', () => {
				console.log('body:', Buffer.concat(body).toString());
			});
		});

		request.on('error', console.error);

		request.write('123');
		request.end('456');
	} catch (error) {
		console.error(error);
	}
})();

// statusCode: 200
// headers: { connection: 'close',
//   server: 'gunicorn/19.9.0',
//   date: 'Sat, 15 Dec 2018 18:19:32 GMT',
//   'content-type': 'application/json',
//   'content-length': '259',
//   'access-control-allow-origin': '*',
//   'access-control-allow-credentials': 'true',
//   via: '1.1 vegur' }
// body: {
//   "args": {},
//   "data": "123456",
//   "files": {},
//   "form": {},
//   "headers": {
//     "Connection": "close",
//     "Content-Length": "6",
//     "Host": "httpbin.org"
//   },
//   "json": 123456,
//   "origin": "xxx.xxx.xxx.xxx",
//   "url": "http://httpbin.org/post"
// }

http2.auto.protocolCache

An instance of quick-lru used for ALPN cache.

There is a maximum of 100 entries. You can modify the limit through protocolCache.maxSize - note that the change will be visible globally.

http2.auto.createResolveProtocol(cache, queue, connect)

cache

Type: Map<string, string>

This is the store where cached ALPN protocols are put into.

queue

Type: Map<string, Promise>

This is the store that contains pending ALPN negotiation promises.

connect

Type: (options, callback) => TLSSocket | Promise<TLSSocket>

See https://github.com/szmarczak/resolve-alpn#connect

http2.auto.resolveProtocol(options)

Returns a Promise<{alpnProtocol: string}>.

http2.request(url, options, callback)

Same as https.request.

options.h2session

Type: Http2Session

The session used to make the actual request. If none provided, it will use options.agent to get one.

http2.get(url, options, callback)

Same as https.get.

new http2.ClientRequest(url, options, callback)

Same as https.ClientRequest.

new http2.IncomingMessage(socket)

Same as https.IncomingMessage.

new http2.Agent(options)

Note: this is not compatible with the classic http.Agent.

Usage example:

const http2 = require('http2-wrapper');

class MyAgent extends http2.Agent {
	createConnection(origin, options) {
		console.log(`Connecting to ${http2.Agent.normalizeOrigin(origin)}`);
		return http2.Agent.connect(origin, options);
	}
}

http2.get({
	hostname: 'google.com',
	agent: new MyAgent()
}, response => {
	response.on('data', chunk => console.log(`Received chunk of ${chunk.length} bytes`));
});

options

Each option is an Agent property and can be changed later.

timeout

Type: number
Default: 0

If there's no activity after timeout milliseconds, the session will be closed. If 0, no timeout is applied.

maxSessions

Type: number
Default: Infinity

The maximum amount of sessions in total.

maxEmptySessions

Type: number
Default: 10

The maximum amount of empty sessions in total. An empty session is a session with no pending requests.

maxCachedTlsSessions

Type: number
Default: 100

The maximum amount of cached TLS sessions.

agent.protocol

Type: string
Default: https:

agent.settings

Type: object
Default: {enablePush: false}

Settings used by the current agent instance.

agent.normalizeOptions(options)

Returns a string representing normalized options.

Agent.normalizeOptions({servername: 'example.com'});
// => ':::::::::::::::::::::::::::::::::::::'

agent.getSession(origin, options)

origin

Type: string URL object

Origin used to create new session.

options

Type: object

Options used to create new session.

Returns a Promise giving free Http2Session. If no free sessions are found, a new one is created.

A session is considered free when pending streams count is less than max concurrent streams settings.

agent.getSession(origin, options, listener)

listener

Type: object

{
	reject: error => void,
	resolve: session => void
}

If the listener argument is present, the Promise will resolve immediately. It will use the resolve function to pass the session.

agent.request(origin, options, headers, streamOptions)

Returns a Promise giving Http2Stream.

agent.createConnection(origin, options)

Returns a new TLSSocket. It defaults to Agent.connect(origin, options).

agent.closeEmptySessions(count)

count

Type: number Default: Number.POSITIVE_INFINITY

Makes an attempt to close empty sessions. Only sessions with 0 concurrent streams will be closed.

agent.destroy(reason)

Destroys all sessions.

agent.emptySessionCount

Type: number

A number of empty sessions.

agent.pendingSessionCount

Type: number

A number of pending sessions.

agent.sessionCount

Type: number

A number of all sessions held by the Agent.

Event: 'session'

agent.on('session', session => {
	// A new session has been created by the Agent.
});

Proxy support

Currently http2-wrapper provides support for these proxies:

• HttpOverHttp2
• HttpsOverHttp2
• Http2OverHttp2
• Http2OverHttp
• Http2OverHttps

Any of the above can be accessed via http2wrapper.proxies. Check out the examples/proxies directory to learn more.

Note: If you use the http2.auto function, the real IP address will leak. http2wrapper is not aware of the context. It will create a connection to the end server using your real IP address to get the ALPN protocol. Then it will create another connection using proxy. To migitate this, you need to pass a custom resolveProtocol function as an option:

const resolveAlpnProxy = new URL('https://username:password@localhost:8000');
const connect = async (options, callback) => new Promise((resolve, reject) => {
	const host = `${options.host}:${options.port}`;

	(async () => {
		try {
			const request = await http2.auto(resolveAlpnProxy, {
				method: 'CONNECT',
				headers: {
					host
				},
				path: host,

				// For demo purposes only!
				rejectUnauthorized: false,
			});

			request.end();

			request.once('error', reject);

			request.once('connect', (response, socket, head) => {
				if (head.length > 0) {
					reject(new Error(`Unexpected data before CONNECT tunnel: ${head.length} bytes`));

					socket.destroy();
					return;
				}

				const tlsSocket = tls.connect({
					...options,
					socket
				}, callback);

				resolve(tlsSocket);
			});
		} catch (error) {
			reject(error);
		}
	})();
});

// This is required to prevent leaking real IP address on ALPN negotiation
const resolveProtocol = http2.auto.createResolveProtocol(new Map(), new Map(), connect);

const request = await http2.auto('https://httpbin.org/anything', {
	agent: {…},
	resolveProtocol
}, response => {
	// Read the response here
});

request.end();

See unknown-over-unknown.js to learn more.

Mirroring another server

See examples/proxies/mirror.js for an example.

WebSockets over HTTP/2

See examples/ws for an example.

Push streams

See examples/push-stream for an example.

Related

• got - Simplified HTTP requests
• http2-proxy - A simple http/2 & http/1.1 spec compliant proxy helper for Node.

License

MIT