SocketClient Component

Async Connector to open TCP/IP and SSL/TLS based connections.

Introduction

Think of this library as an async version of fsockopen() or stream_socket_client().

Before you can actually transmit and receive data to/from a remote server, you have to establish a connection to the remote end. Establishing this connection through the internet/network takes some time as it requires several steps in order to complete:

1. Resolve remote target hostname via DNS (+cache)
2. Complete TCP handshake (2 roundtrips) with remote target IP:port
3. Optionally enable SSL/TLS on the new resulting connection

Usage

In order to use this project, you'll need the following react boilerplate code to initialize the main loop and select your DNS server if you have not already set it up anyway.

$loop = React\EventLoop\Factory::create();

$dnsResolverFactory = new React\Dns\Resolver\Factory();
$dns = $dnsResolverFactory->createCached('8.8.8.8', $loop);

Async TCP/IP connections

The React\SocketClient\Connector provides a single promise-based create($host, $ip) method which resolves as soon as the connection succeeds or fails.

$connector = new React\SocketClient\Connector($loop, $dns);

$connector->create('www.google.com', 80)->then(function (React\Stream\Stream $stream) {
    $stream->write('...');
    $stream->close();
});

$loop->run();

Async SSL/TLS connections

The SecureConnector class decorates a given Connector instance by enabling SSL/TLS encryption as soon as the raw TCP/IP connection succeeds. It provides the same promise- based create($host, $ip) method which resolves with a Stream instance that can be used just like any non-encrypted stream.

$secureConnector = new React\SocketClient\SecureConnector($connector, $loop);

$secureConnector->create('www.google.com', 443)->then(function (React\Stream\Stream $stream) {
    $stream->write("GET / HTTP/1.0\r\nHost: www.google.com\r\n\r\n");
    ...
});

$loop->run();

Advanced usage: Internally, the SecureConnector has to set the required context options on the underlying stream resource. It should therefor be used with a Connector somewhere in the connector stack so that it can allocate an empty context resource for each stream resource. Failing to do so may result in some hard to trace race conditions, because all stream resources will use a single, shared default context resource otherwise.

Unix domain sockets

Similarly, the UnixConnector class can be used to connect to Unix domain socket (UDS) paths like this:

$connector = new React\SocketClient\UnixConnector($loop);

$connector->create('/tmp/demo.sock')->then(function (React\Stream\Stream $stream) {
    $stream->write("HELLO\n");
});

$loop->run();