Quick start

This page wires the smallest end-to-end integration: daemon up, client connects to an OPC UA server through the daemon, reads one value, exits. Subsequent runs reuse the same session — that is the whole point.

1 — Start the daemon

vendor/bin/opcua-session-manager

Leave it running in the foreground for now. In production you wrap it in systemd — see Daemon · Running as a service.

2 — Connect and read

<?php

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

use PhpOpcua\SessionManager\Client\ManagedClient;
use PhpOpcua\Client\Types\NodeId;
use PhpOpcua\Client\Types\StatusCode;

$client = new ManagedClient(
    socketPath: '/tmp/opcua-session-manager.sock',
    timeout: 30.0,
);

$client->connect('opc.tcp://localhost:4840');

$dv = $client->read(NodeId::numeric(0, 2261));   // ProductName

if (StatusCode::isGood($dv->statusCode)) {
    echo "Connected to: " . $dv->getValue() . "\n";
}

$client->disconnect();

Run it twice. The first run pays the OPC UA handshake cost; the second run reuses the same daemon-held session and the read is ~10× faster.

3 — Verify the reuse

$client->connect('opc.tcp://localhost:4840');

if ($client->wasSessionReused()) {
    echo "Reusing existing session — no handshake.\n";
} else {
    echo "Fresh session — first connect from this configuration.\n";
}

wasSessionReused() is the ManagedClient-specific accessor that tells you whether the last connect() matched an existing session keyed by the same (endpointUrl, sanitized config) pair. See ManagedClient · Session reuse.

4 — What disconnect does (and does not)

$client->disconnect();

ManagedClient::disconnect() sends a close IPC command to the daemon. The daemon performs CloseSession against the OPC UA server and removes the entry from its session store. The daemon-side session is gone when disconnect() returns; the next connect() with the same config pays the OPC UA handshake again.

To keep the daemon session alive across multiple requests so the reuse machinery can do its job, do not call disconnect() between requests — keep the ManagedClient instance alive (singleton bind in Laravel, long-running worker) and let the daemon's inactivity timeout (--timeout, default 600 s) reclaim idle sessions when nothing references them.

To bypass reuse on a particular connect call (force a fresh session even if one matches):

$client->connectForceNew('opc.tcp://localhost:4840');

connectForceNew() is the escape hatch for session isolation (per-test scenarios, manual session resets). See ManagedClient · Opening and closing.

5 — Where to go next

The ManagedClient reads, writes, browses, subscribes — every method on OpcUaClientInterface works. For the operation pages themselves (read, browse, subscribe, …), the documentation lives in opcua-client:

• opcua-client/doc/04-reading-writing.md
• opcua-client/doc/03-browsing.md
• opcua-client/doc/06-subscriptions.md

In this documentation the focus is on what changes when you go through the daemon:

• Why a session manager — the mental model.
• ManagedClient · Overview — what the wrapper does and what it does not.
• ManagedClient · Differences from the direct client — side-by-side comparison.