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CXLVI. Socket Functions
The socket extension implements a low-level interface to the socket
communication functions based on the popular BSD sockets, providing the
possibility to act as a socket server as well as a client.
For a more generic client-side socket interface, see
stream_socket_client(),
stream_socket_server(),
fsockopen(), and
pfsockopen().
When using these functions, it is important to remember that while
many of them have identical names to their C counterparts, they
often have different declarations. Please be sure to read the
descriptions to avoid confusion.
Those unfamiliar with socket programming can find a lot
of useful material in the appropriate Unix man pages, and there is a great
deal of tutorial information on socket programming in C on the web, much
of which can be applied, with slight modifications, to socket programming
in PHP. The Unix Socket
FAQ might be a good start.
No external libraries are needed to build this extension.
The socket functions described here are part of an extension to
PHP which must be enabled at compile time by giving the --enable-sockets option to
configure.
Note: IPv6 Support was added with PHP 5.0.0.
This extension has no configuration directives defined in php.ini. This extension has no resource types defined.
The constants below are defined by this extension, and
will only be available when the extension has either
been compiled into PHP or dynamically loaded at runtime.
The socket extension was written to provide a usable interface to the
powerful BSD sockets. Care has been taken that the functions work equally
well on Win32 and Unix implementations. Almost all of the sockets
functions may fail under certain conditions and therefore emit an
E_WARNING message describing the error. Sometimes this
doesn't happen to the desire of the developer. For example the function
socket_read() may suddenly emit an
E_WARNING message because the connection broke
unexpectedly. It's common to suppress the warning with the
@-operator and catch the error code within the
application with the socket_last_error() function. You
may call the socket_strerror() function with this error
code to retrieve a string describing the error. See their description for
more information.
Note:
The E_WARNING messages generated by the socket
extension are in English though the retrieved error message will appear
depending on the current locale (LC_MESSAGES):
Warning - socket_bind() unable to bind address [98]: Die Adresse wird bereits verwendet |
Example 1. Socket example: Simple TCP/IP server
This example shows a simple talkback server. Change the
address and port variables
to suit your setup and execute. You may then connect to the
server with a command similar to: telnet 192.168.1.53
10000 (where the address and port match your
setup). Anything you type will then be output on the server
side, and echoed back to you. To disconnect, enter 'quit'.
#!/usr/local/bin/php -q
<?php
error_reporting(E_ALL);
/* Allow the script to hang around waiting for connections. */
set_time_limit(0);
/* Turn on implicit output flushing so we see what we're getting
* as it comes in. */
ob_implicit_flush();
$address = '192.168.1.53';
$port = 10000;
if (($sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) < 0) {
echo "socket_create() failed: reason: " . socket_strerror($sock) . "\n";
}
if (($ret = socket_bind($sock, $address, $port)) < 0) {
echo "socket_bind() failed: reason: " . socket_strerror($ret) . "\n";
}
if (($ret = socket_listen($sock, 5)) < 0) {
echo "socket_listen() failed: reason: " . socket_strerror($ret) . "\n";
}
do {
if (($msgsock = socket_accept($sock)) < 0) {
echo "socket_accept() failed: reason: " . socket_strerror($msgsock) . "\n";
break;
}
/* Send instructions. */
$msg = "\nWelcome to the PHP Test Server. \n" .
"To quit, type 'quit'. To shut down the server type 'shutdown'.\n";
socket_write($msgsock, $msg, strlen($msg));
do {
if (false === ($buf = socket_read($msgsock, 2048, PHP_NORMAL_READ))) {
echo "socket_read() failed: reason: " . socket_strerror($ret) . "\n";
break 2;
}
if (!$buf = trim($buf)) {
continue;
}
if ($buf == 'quit') {
break;
}
if ($buf == 'shutdown') {
socket_close($msgsock);
break 2;
}
$talkback = "PHP: You said '$buf'.\n";
socket_write($msgsock, $talkback, strlen($talkback));
echo "$buf\n";
} while (true);
socket_close($msgsock);
} while (true);
socket_close($sock);
?> |
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Example 2. Socket example: Simple TCP/IP client
This example shows a simple, one-shot HTTP client. It simply
connects to a page, submits a HEAD request, echoes the reply,
and exits.
<?php
error_reporting(E_ALL);
echo "<h2>TCP/IP Connection</h2>\n";
/* Get the port for the WWW service. */
$service_port = getservbyname('www', 'tcp');
/* Get the IP address for the target host. */
$address = gethostbyname('www.example.com');
/* Create a TCP/IP socket. */
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if ($socket < 0) {
echo "socket_create() failed: reason: " . socket_strerror($socket) . "\n";
} else {
echo "OK.\n";
}
echo "Attempting to connect to '$address' on port '$service_port'...";
$result = socket_connect($socket, $address, $service_port);
if ($result < 0) {
echo "socket_connect() failed.\nReason: ($result) " . socket_strerror($result) . "\n";
} else {
echo "OK.\n";
}
$in = "HEAD / HTTP/1.1\r\n";
$in .= "Host: www.example.com\r\n";
$in .= "Connection: Close\r\n\r\n";
$out = '';
echo "Sending HTTP HEAD request...";
socket_write($socket, $in, strlen($in));
echo "OK.\n";
echo "Reading response:\n\n";
while ($out = socket_read($socket, 2048)) {
echo $out;
}
echo "Closing socket...";
socket_close($socket);
echo "OK.\n\n";
?> |
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use_soap_error_handler
