__construct Method

void AsyncTcpConnection::__construct(string $remote_address, $context_option = null)

Creates an asynchronous connection object.

AsyncTcpConnection allows Workerman to initiate asynchronous connections to remote servers as a client, and to asynchronously send and process data on the connection using the send interface and onMessage callback.

Parameters

Parameter: remote_address

The address of the connection, for example:

• tcp://www.baidu.com:80
• ssl://www.baidu.com:443
• ws://echo.websocket.org:80
• frame://192.168.1.1:8080
• text://192.168.1.1:8080

Parameter: $context_option

Requires this parameter (workerman >= 3.3.5).

Used to set the socket context, for example, using bindto to specify which (network card) IP and port to access the external network, setting SSL certificates, etc.

See stream_context_create, Socket Context Options, and SSL Context Options.

Note

Currently, AsyncTcpConnection supports protocols such as tcp, ssl, ws, frame, and text.

Custom protocols are also supported, see How to Define Protocols.

The use of ssl requires Workerman >= 3.3.4 and the installation of the openssl extension.

AsyncTcpConnection currently does not support the http protocol.

You can use new AsyncTcpConnection('ws://...') to initiate a WebSocket connection to a remote WebSocket server in Workerman, similar to a browser. Refer to the example. However, it is not possible to initiate a WebSocket connection in Workerman using new AsyncTcpConnection('websocket://...').

Examples

Example 1: Asynchronously access external HTTP service

use Workerman\Worker;
use Workerman\Connection\AsyncTcpConnection;

require_once __DIR__ . '/vendor/autoload.php';

$task = new Worker();

$task->onWorkerStart = function($task) {
    $connection_to_baidu = new AsyncTcpConnection('tcp://www.baidu.com:80');

    $connection_to_baidu->onConnect = function(AsyncTcpConnection $connection_to_baidu) {
        echo "connect success\n";
        $connection_to_baidu->send("GET / HTTP/1.1\r\nHost: www.baidu.com\r\nConnection: keep-alive\r\n\r\n");
    };

    $connection_to_baidu->onMessage = function(AsyncTcpConnection $connection_to_baidu, $http_buffer) {
        echo $http_buffer;
    };

    $connection_to_baidu->onClose = function(AsyncTcpConnection $connection_to_baidu) {
        echo "connection closed\n";
    };

    $connection_to_baidu->onError = function(AsyncTcpConnection $connection_to_baidu, $code, $msg) {
        echo "Error code:$code msg:$msg\n";
    };

    $connection_to_baidu->connect();
};

Worker::runAll();

Example 2: Asynchronously access external WebSocket service and set the local IP and port for access

<?php
use Workerman\Worker;
use Workerman\Connection\AsyncTcpConnection;

require_once __DIR__ . '/vendor/autoload.php';

$worker = new Worker();

$worker->onWorkerStart = function($worker){
    $context_option = array(
        'socket' => array(
            'bindto' => '114.215.84.87:2333',
        ),
    );

    $con = new AsyncTcpConnection('ws://echo.websocket.org:80', $context_option);

    $con->onConnect = function(AsyncTcpConnection $con) {
        $con->send('hello');
    };

    $con->onMessage = function(AsyncTcpConnection $con, $data) {
        echo $data;
    };

    $con->connect();
};

Worker::runAll();

Example 3: Asynchronously access external wss port and set the local SSL certificate

<?php
use Workerman\Worker;
use Workerman\Connection\AsyncTcpConnection;

require_once __DIR__ . '/vendor/autoload.php';

$worker = new Worker();

$worker->onWorkerStart = function($worker){
    $context_option = array(
        'socket' => array(
            'bindto' => '114.215.84.87:2333',
        ),
        'ssl' => array(
            'local_cert'        => '/your/path/to/pemfile',
            'passphrase'        => 'your_pem_passphrase',
            'allow_self_signed' => true,
            'verify_peer'       => false
        )
    );

    $con = new AsyncTcpConnection('ws://echo.websocket.org:443', $context_option);

    $con->transport = 'ssl';

    $con->onConnect = function(AsyncTcpConnection $con) {
        $con->send('hello');
    };

    $con->onMessage = function(AsyncTcpConnection $con, $data) {
        echo $data;
    };

    $con->connect();
};

Worker::runAll();