socket_recv
(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)
socket_recv — Receives data from a connected socket
Description
The socket_recv() function receives
length
bytes of data in data
from
socket
. socket_recv() can
be used to gather data from connected sockets. Additionally, one or
more flags can be specified to modify the behaviour of the
function.
data
is passed by reference, so it must be
specified as a variable in the argument list. Data read from
socket
by socket_recv()
will be returned in data
.
Parameters
-
socket
-
The
socket
must be a Socket instance previously created by socket_create(). -
data
-
The data received will be fetched to the variable specified with
data
. If an error occurs, if the connection is reset, or if no data is available,data
will be set tonull
. -
length
-
Up to
length
bytes will be fetched from remote host. -
flags
-
The value of
flags
can be any combination of the following flags, joined with the binary OR (|
) operator.Possible values for flags
Flag Description MSG_OOB
Process out-of-band data. MSG_PEEK
Receive data from the beginning of the receive queue without removing it from the queue. MSG_WAITALL
Block until at least length
are received. However, if a signal is caught or the remote host disconnects, the function may return less data.MSG_DONTWAIT
With this flag set, the function returns even if it would normally have blocked.
Return Values
socket_recv() returns the number of bytes received,
or false
if there was an 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.
Changelog
Version | Description |
---|---|
8.0.0 |
socket is a Socket instance now;
previously, it was a resource.
|
Examples
Example #1 socket_recv() example
This example is a simple rewrite of the first example from Examples to use socket_recv().
<?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 === false) {
echo "socket_create() failed: reason: " . socket_strerror(socket_last_error()) . "\n";
} else {
echo "OK.\n";
}
echo "Attempting to connect to '$address' on port '$service_port'...";
$result = socket_connect($socket, $address, $service_port);
if ($result === false) {
echo "socket_connect() failed.\nReason: ($result) " . socket_strerror(socket_last_error($socket)) . "\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";
$buf = 'This is my buffer.';
if (false !== ($bytes = socket_recv($socket, $buf, 2048, MSG_WAITALL))) {
echo "Read $bytes bytes from socket_recv(). Closing socket...";
} else {
echo "socket_recv() failed; reason: " . socket_strerror(socket_last_error($socket)) . "\n";
}
socket_close($socket);
echo $buf . "\n";
echo "OK.\n\n";
?>
The above example will produce something like:
<h2>TCP/IP Connection</h2> OK. Attempting to connect to '208.77.188.166' on port '80'...OK. Sending HTTP HEAD request...OK. Reading response: Read 123 bytes from socket_recv(). Closing socket...HTTP/1.1 200 OK Date: Mon, 14 Sep 2009 08:56:36 GMT Server: Apache/2.2.3 (Red Hat) Last-Modified: Tue, 15 Nov 2005 13:24:10 GMT ETag: "b80f4-1b6-80bfd280" Accept-Ranges: bytes Content-Length: 438 Connection: close Content-Type: text/html; charset=UTF-8 OK.