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Last updated: Fri, 26 Jan 2007

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# socket_create

(PHP 4 >= 4.1.0, PHP 5)

socket_create -- Create a socket (endpoint for communication)

## Description

resource socket_create ( int domain, int type, int protocol )

Creates and returns a socket resource, also referred to as an endpoint of communication. A typical network connection is made up of 2 sockets, one performing the role of the client, and another performing the role of the server.

The `domain` parameter specifies the protocol family to be used by the socket.

Таблица 1. Available address/protocol families

Domain | Description
--- | ---
AF_INET | IPv4 Internet based protocols. TCP and UDP are common protocols of this protocol family.
AF_INET6 | IPv6 Internet based protocols. TCP and UDP are common protocols of this protocol family. Support added in PHP 5.0.0.
AF_UNIX | Local communication protocol family. High efficiency and low overhead make it a great form of IPC (Interprocess Communication).

The `type` parameter selects the type of communication to be used by the socket.

Таблица 2. Available socket types

Type | Description
--- | ---
SOCK_STREAM | Provides sequenced, reliable, full-duplex, connection-based byte streams. An out-of-band data transmission mechanism may be supported. The TCP protocol is based on this socket type.
SOCK_DGRAM | Supports datagrams (connectionless, unreliable messages of a fixed maximum length). The UDP protocol is based on this socket type.
SOCK_SEQPACKET | Provides a sequenced, reliable, two-way connection-based data transmission path for datagrams of fixed maximum length; a consumer is required to read an entire packet with each read call.
SOCK_RAW | Provides raw network protocol access. This special type of socket can be used to manually construct any type of protocol. A common use for this socket type is to perform ICMP requests (like ping, traceroute, etc).
SOCK_RDM | Provides a reliable datagram layer that does not guarantee ordering. This is most likely not implemented on your operating system.

The `protocol` parameter sets the specific protocol within the specified `domain` to be used when communicating on the returned socket. The proper value can be retrieved by name by using getprotobyname(). If the desired protocol is TCP, or UDP the corresponding constants `SOL_TCP`, and `SOL_UDP` can also be used.

Таблица 3. Common protocols

Name | Description
--- | ---
icmp | The Internet Control Message Protocol is used primarily by gateways and hosts to report errors in datagram communication. The "ping" command (present in most modern operating systems) is an example application of ICMP.
udp | The User Datagram Protocol is a connectionless, unreliable, protocol with fixed record lengths. Due to these aspects, UDP requires a minimum amount of protocol overhead.
tcp | The Transmission Control Protocol is a reliable, connection based, stream oriented, full duplex protocol. TCP guarantees that all data packets will be received in the order in which they were sent. If any packet is somehow lost during communication, TCP will automatically retransmit the packet until the destination host acknowledges that packet. For reliability and performance reasons, the TCP implementation itself decides the appropriate octet boundaries of the underlying datagram communication layer. Therefore, TCP applications must allow for the possibility of partial record transmission.

socket_create() Returns a socket resource on success, or `FALSE` on error. The actual error code can be retrieved by calling socket_last_error(). This error code may be passed to socket_strerror() to get a textual explanation of the error.

> Замечание: If an invalid `domain` or `type` is given, socket_create() defaults to `AF_INET` and `SOCK_STREAM` respectively and additionally emits an `E_WARNING` message.

See also socket_accept(), socket_bind(), socket_connect(), socket_listen(), socket_last_error(), and socket_strerror().

add a note User Contributed Notes
socket_create
gancheff at gmail dot com
05-Feb-2007 03:14
`here's a way to get the currency:
example getCurrency("BGN", "USD");
function getCurrency($from, $to, $cache = true) {
if ($cache && $_SESSION['currency'][$from][$to]['value'] &&
(time() - $_SESSION['currency'][$from][$to]['time']) < 3600)
return $_SESSION['currency'][$from][$to]['value'];
$host = "www.xe.com";
$port = "80";
$data = "Amount=1&From=" . strtoupper($from) . "&To=" . strtoupper($to);
$header =
"POST /ucc/convert.cgi HTTP/1.1\n" .
"Host: $host:$port\n" .
"Content-Type: application/x-www-form-urlencoded\n" .
"Content-Length: " . strlen($data) . "\n\n" .
$data . "\n";
$s = socket_create(AF_INET, SOCK_STREAM, 0);
$z = socket_connect($s, gethostbyname($host), $port);
socket_write ($s, $header, strlen($header));
while (true) {
$c = @socket_read($s, 1);
if ($c == "\n") {
if (preg_match("/$from = (.+) $to/i", $line, $matches) ||
preg_match("/<\/html>/i", $line)) break;
$line = "";
} else $line .= $c;
}
socket_close($s);
$_SESSION['currency'][$from][$to]['time'] = time();
$_SESSION['currency'][$from][$to]['value'] = str_pad(round($matches[1], 5), 7, "0");
return ($matches[1]) ? str_pad(round($matches[1], 5), 7, "0") : "0.00000";
}`
ionic at ionic dot de
21-Jan-2007 03:39
`To david _at* eder #do; us:
Dependent on your system, you could, at least on LINUX, use exec with "/sbin/ifconfig eth0 | awk '/inet /{ print substr($2,9) }'" (also working for non-root users), that will work a little bit faster as your PHP function.
Though, we should keep in mind that users with safe_mode enabled are more or less forced to use the socket thing. :)`
jens at surefoot dot com
08-Aug-2006 05:46
`Please be aware that RAW sockets (as used for the ping example) are restricted to root accounts on *nix systems. Since web servers hardly ever run as root, they won't work on webpages.
On Windows based servers it should work regardless.`
06-Jan-2006 02:36
`Here's a ping function that uses sockets instead of exec(). Note: I was unable to get socket_create() to work without running from CLI as root. I've already calculated the package's checksum to simplify the code (the message is 'ping' but it doesn't actually matter).
<?php
function ping($host) {
$package = "\x08\x00\x19\x2f\x00\x00\x00\x00\x70\x69\x6e\x67";
/* create the socket, the last '1' denotes ICMP */
$socket = socket_create(AF_INET, SOCK_RAW, 1);
/* set socket receive timeout to 1 second */
socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, array("sec" => 1, "usec" => 0));
/* connect to socket */
socket_connect($socket, $host, null);
/* record start time */
list($start_usec, $start_sec) = explode(" ", microtime());
$start_time = ((float) $start_usec + (float) $start_sec);
socket_send($socket, $package, strlen($package), 0);
if(@socket_read($socket, 255)) {
list($end_usec, $end_sec) = explode(" ", microtime());
$end_time = ((float) $end_usec + (float) $end_sec);
$total_time = $end_time - $start_time;
return $total_time;
} else {
return false;
}
socket_close($socket);
}
?>`
kyle gibson
28-Oct-2005 05:48
`Took me about 20 minutes to figure out the proper arguments to supply for a AF_UNIX socket. Anything else, and I would get a PHP warning about the 'type' not being supported. I hope this saves someone else time.
<?php
$socket = socket_create(AF_UNIX, SOCK_STREAM, 0);
// code
?>`
david at eder dot us
25-Jan-2005 11:42
`Sometimes when you are running CLI, you need to know your own ip address.
<?php
$addr = my_ip();
echo "my ip address is $addr\n";
function my_ip($dest='64.0.0.0', $port=80)
{
$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
socket_connect($socket, $dest, $port);
socket_getsockname($socket, $addr, $port);
socket_close($socket);
return $addr;
}
?>`
david at eder dot us
08-Jun-2004 08:07
`Seems there aren't any examples of UDP clients out there. This is a tftp client. I hope this makes someone's life easier.
<?php
function tftp_fetch($host, $filename)
{
$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
// create the request packet
$packet = chr(0) . chr(1) . $filename . chr(0) . 'octet' . chr(0);
// UDP is connectionless, so we just send on it.
socket_sendto($socket, $packet, strlen($packet), 0x100, $host, 69);
$buffer = '';
$port = '';
$ret = '';
do
{
// $buffer and $port both come back with information for the ack
// 516 = 4 bytes for the header + 512 bytes of data
socket_recvfrom($socket, $buffer, 516, 0, $host, $port);
// add the block number from the data packet to the ack packet
$packet = chr(0) . chr(4) . substr($buffer, 2, 2);
// send ack
socket_sendto($socket, $packet, strlen($packet), 0, $host, $port);
// append the data to the return variable
// for large files this function should take a file handle as an arg
$ret .= substr($buffer, 4);
}
while(strlen($buffer) == 516); // the first non-full packet is the last.
return $ret;
}
?>`
evan at coeus hyphen group dot com
14-Feb-2002 06:33
`Okay I talked with Richard a little (via e-mail). We agree that getprotobyname() and using the constants should be the same in functionality and speed, the use of one or the other is merely coding style. Personally, we both think the constants are prettier :).
The eight different protocols are the ones implemented in PHP- not the total number in existance (RFC 1340 has 98).
All we disagree on is using 0- Richard says that "accordning to the official unix/bsd sockets 0 is more than fine." I think that since 0 is a reserved number according to RFC 1320, and when used usually refers to IP, not one of it's sub-protocols (TCP, UDP, etc.)`
email at NOSPAMrichard-samar dot de
13-Feb-2002 01:10
`Actually, you don't need to use
getprotobyname("tcp") but instead can use
the constants: SOL_TCP and SOL_UDP.
Here an extract of the source from
ext/sockets which should make this clear.
if ((pe = getprotobyname("tcp"))) {
REGISTER_LONG_CONSTANT("SOL_TCP", pe->p_proto,
CONST_CS | CONST_PERSISTENT);
}
Normally the third parameter can be set to 0. In the
original BSD Socket implementation the third parameter
(there are 8 different types, here only two) should be
IPPROTO_TCP or IPPROTO_UPD (or one of the 6 others ones).
These two parameters are though not warpped in PHP as
constants and therefore not available.
Please use SOL_TCP and SOL_UDP. e.g.:
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
Please be aware of the fact that UDP
and TCP can only be used with AF_INET which is: "Adress Family Internet". With UNIX Domain sockets TCP/UDP would make no sense!
best regards
-Richard-Moh Samar`
add a note
socket_get_option socket_create_pair

Last updated: Fri, 26 Jan 2007
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