plc-sim/client/node_modules/http2-wrapper

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.

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:', // Note the `http:` protocol here
	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.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.

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()
}, res => {
	res.on('data', chunk => console.log(`Received chunk of ${chunk.length} bytes`));
});

options

Each option is assigned to each Agent instance and can be changed later.

timeout

Type: number
Default: 60000

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

maxSessions

Type: number
Default: Infinity

The maximum amount of sessions in total.

maxFreeSessions

Type: number
Default: 10

The maximum amount of free sessions in total. This only applies to sessions with no pending requests.

Note: It is possible that the amount will be exceeded when sessions have at least 1 pending request.

maxCachedTlsSessions

Type: number
Default: 100

The maximum amount of cached TLS sessions.

Agent.normalizeOrigin(url)

Returns a string representing the origin of the URL.

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'});
// => ':example.com'

agent.getSession(origin, options)

origin

Type: string URL object

An origin used to create new session.

options

Type: object

The options used to create new session.

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

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.closeFreeSessions()

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

agent.destroy(reason)

Destroys all sessions.

Event: 'session'

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

Proxy support

An example of a full-featured proxy server can be found here. It supports mirroring, custom authorities and the CONNECT protocol.

Mirroring

To mirror another server we need to use only http2-proxy. We don't need the CONNECT protocol or custom authorities.

To see the result, just navigate to the server's address.

HTTP/1 over HTTP/2

Since we don't care about mirroring, the server needs to support the CONNECT protocol in this case.

The client looks like this:

const https = require('https');
const http2 = require('http2');

const session = http2.connect('https://localhost:8000', {
	// For demo purposes only!
	rejectUnauthorized: false
});

session.ref();

https.request('https://httpbin.org/anything', {
	createConnection: options => {
		return session.request({
			':method': 'CONNECT',
			':authority': `${options.host}:${options.port}`
		});
	}
}, 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());

		session.unref();
	});
}).end();

HTTP/2 over HTTP/2

It's a tricky one! We cannot create an HTTP/2 session on top of an HTTP/2 stream. But... we can still specify the :authority header, no need to use the CONNECT protocol here.

The client looks like this:

const http2 = require('../../source');
const {Agent} = http2;

class ProxyAgent extends Agent {
	constructor(url, options) {
		super(options);

		this.origin = url;
	}

	request(origin, sessionOptions, headers, streamOptions) {
		return super.request(this.origin, sessionOptions, {
			...headers,
			':authority': (new URL(origin)).host
		}, streamOptions);
	}
}

const request = http2.request({
	hostname: 'httpbin.org',
	protocol: 'https:',
	path: '/anything',
	agent: new ProxyAgent('https://localhost:8000'),
	// For demo purposes only!
	rejectUnauthorized: false
}, 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.end();

Notes

• If you're interested in WebSockets over HTTP/2, then check out this discussion.
• HTTP/2 sockets cannot be malformed, therefore modifying the socket will have no effect.
• You can make a custom Agent to support push streams.

Benchmarks

CPU: Intel i7-7700k (governor: performance)
Server: H2O v2.2.5 h2o.conf
Node: v14.5.0 Linux: 5.6.18-156.current

auto means http2wrapper.auto.

http2-wrapper                         x 12,181 ops/sec ±3.39% (75 runs sampled)
http2-wrapper - preconfigured session x 13,140 ops/sec ±2.51% (79 runs sampled)
http2-wrapper - auto                  x 11,412 ops/sec ±2.55% (78 runs sampled)
http2                                 x 16,050 ops/sec ±1.39% (86 runs sampled)
https         - auto - keepalive      x 12,288 ops/sec ±2.69% (79 runs sampled)
https                - keepalive      x 12,155 ops/sec ±3.32% (78 runs sampled)
https                                 x 1,604 ops/sec  ±2.03% (77 runs sampled)
http                                  x 6,041 ops/sec  ±3.82% (76 runs sampled)
Fastest is http2

http2-wrapper:

• 32% less performant than http2
• as performant as https - keepalive
• 100% more performant than http

http2-wrapper - preconfigured session:

• 22% less performant than http2
• 8% more performant than https - keepalive
• 118% more performant than http

http2-wrapper - auto:

• 41% less performant than http2
• 8% less performant than https - keepalive
• 89% more performant than http

https - auto - keepalive:

• 31% less performant than http2
• as performant as https - keepalive
• 103% more performant than http

Related

• got - Simplified HTTP requests

License

MIT