Installation

php-opcua/opcua-client-ext-reverse-connect is distributed through Packagist. Its only required dependency is php-opcua/opcua-client v4.4.0 or newer — the version that introduced TcpTransport::fromConnectedSocket() and the matching ManagesConnectionTrait adjustment the listener relies on.

Requirements

• PHP ≥ 8.2
• php-opcua/opcua-client ≥ 4.4
• psr/log ^3.0 and psr/event-dispatcher ^1.0 — both already declared as transitive dependencies of opcua-client

There is no native extension to enable. The listener uses the standard PHP streams API (stream_socket_server, stream_socket_accept, stream_select) — available everywhere PHP runs.

Install

composer require php-opcua/opcua-client-ext-reverse-connect

That is the only step. The package autoloads under the PhpOpcua\Client\ExtReverseConnect\ namespace via PSR-4.

Verify

<?php

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

use PhpOpcua\Client\ExtReverseConnect\ReverseConnectListener;
use PhpOpcua\Client\ExtReverseConnect\ReverseHelloValidator;

$listener = new ReverseConnectListener(
    bindHost: '127.0.0.1',
    bindPort: 0,
    validator: new ReverseHelloValidator(['urn:example']),
);
$listener->listen();
echo "Listener bound on " . $listener->getBindAddress() . PHP_EOL;
$listener->close();

A successful run prints Listener bound on 127.0.0.1:<port>, where <port> is the kernel-assigned ephemeral port.

Running against the test server

The integration tests and the example script under examples/exts/reverse-connect/ use the OPC UA test server from php-opcua/uanetstandard-test-suite v1.4.0+. That release adds two Method nodes — TestServer/ReverseConnect/StartReverseConnect and TestServer/ReverseConnect/StopReverseConnect — that let a regular client trigger the server-side outbound dial:

git clone https://github.com/php-opcua/uanetstandard-test-suite.git
cd uanetstandard-test-suite
docker compose up -d opcua-no-security

The opcua-no-security service exposes port 4840 and includes extra_hosts: ["host.docker.internal:host-gateway"] so the in-container server can reach a listener that lives on the docker host.

What next

• Quick start — accept your first ReverseHello in about 20 lines of PHP.
• How Reverse Connect works — wire format, security model, and where it fits in the OPC UA stack.