Create an Internet or Unix domain server socket

Description

stream_socket_server(
    string $address,
    int &$error_code = null,
    string &$error_message = null,
    int $flags = STREAM_SERVER_BIND | STREAM_SERVER_LISTEN,
    ?resource $context = null
): resource|false

Creates a stream or datagram socket on the specified address.

This function only creates a socket, to begin accepting connections use stream_socket_accept().

Parameters

address

The type of socket created is determined by the transport specified using standard URL formatting: transport://target.

For Internet Domain sockets (AF_INET) such as TCP and UDP, the target portion of the remote_socket parameter should consist of a hostname or IP address followed by a colon and a port number. For Unix domain sockets, the target portion should point to the socket file on the filesystem.

Depending on the environment, Unix domain sockets may not be available. A list of available transports can be retrieved using stream_get_transports(). See List of Supported Socket Transports for a list of bulitin transports.

error_code

If the optional error_code and error_message arguments are present they will be set to indicate the actual system level error that occurred in the system-level socket(), bind(), and listen() calls. If the value returned in error_code is 0 and the function returned false, it is an indication that the error occurred before the bind() call. This is most likely due to a problem initializing the socket. Note that the error_code and error_message arguments will always be passed by reference.

error_message

See error_code description.

flags

A bitmask field which may be set to any combination of socket creation flags.

Note:
For UDP sockets, you must use STREAM_SERVER_BIND as the flags parameter.

context

Return Values

Returns the created stream, or false on error.

Changelog

Version	Description
8.0.0	`context` is nullable now.

Examples

Example #1 Using TCP server sockets

<?php
$socket = stream_socket_server("tcp://0.0.0.0:8000", $errno, $errstr);
if (!$socket) {
  echo "$errstr ($errno)<br />\n";
} else {
  while ($conn = stream_socket_accept($socket)) {
    fwrite($conn, 'The local time is ' . date('n/j/Y g:i a') . "\n");
    fclose($conn);
  }
  fclose($socket);
}
?>

The example below shows how to act as a time server which can respond to time queries as shown in an example on stream_socket_client().

Note: Most systems require root access to create a server socket on a port below 1024.

Example #2 Using UDP server sockets

<?php
$socket = stream_socket_server("udp://127.0.0.1:1113", $errno, $errstr, STREAM_SERVER_BIND);
if (!$socket) {
    die("$errstr ($errno)");
}

do {
    $pkt = stream_socket_recvfrom($socket, 1, 0, $peer);
    echo "$peer\n";
    stream_socket_sendto($socket, date("D M j H:i:s Y\r\n"), 0, $peer);
} while ($pkt !== false);

?>

Notes

Note: When specifying a numerical IPv6 address (e.g. fe80::1), you must enclose the IP in square brackets—for example, tcp://[fe80::1]:80.

stream_socket_server