Socket context options

Description

Socket context options are available for all wrappers that work over sockets, like tcp, http and ftp.

Options

bindto

Used to specify the IP address (either IPv4 or IPv6) and/or the port number that PHP will use to access the network. The syntax is ip:port for IPv4 addresses, and [ip]:port for IPv6 addresses. Setting the IP or the port to 0 will let the system choose the IP and/or port.

Note

As FTP creates two socket connections during normal operation, the port number cannot be specified using this option.

backlog

Used to limit the number of outstanding connections in the socket's listen queue.

Note

This is only applicable to stream_socket_server().

ipv6_v6only

Overrides the OS default regarding mapping IPv4 into IPv6.

Note

This is important in particular when trying to listen on IPv4 addresses separately while there exists a binding on [::].

This is only applicable to stream_socket_server().

so_reuseport

Allows multiple bindings to a same ip:port pair, even from separate processes.

Note

This is only applicable to stream_socket_server().

so_broadcast

Enables sending and receiving data to/from broadcast addresses.

Note

This is only applicable to stream_socket_server().

tcp_nodelay

Setting this option to true will set SOL_TCP,NO_DELAY=1 appropriately, thus disabling the TCP Nagle algorithm.

Changelog

Examples

Basic bindto usage example

<?php
// connect to the internet using the '192.168.0.100' IP
$opts = array(
    'socket' => array(
        'bindto' => '192.168.0.100:0',
    ),
);


// connect to the internet using the '192.168.0.100' IP and port '7000'
$opts = array(
    'socket' => array(
        'bindto' => '192.168.0.100:7000',
    ),
);


// connect to the internet using the '2001:db8::1' IPv6 address
// and port '7000'
$opts = array(
    'socket' => array(
        'bindto' => '[2001:db8::1]:7000',
    ),
);


// connect to the internet using port '7000'
$opts = array(
    'socket' => array(
        'bindto' => '0:7000',
    ),
);


// create the context...
$context = stream_context_create($opts);

// ...and use it to fetch the data
echo file_get_contents('http://www.example.com', false, $context);

?>