socket_read
socket_recvfrom
Socket Functions
PHP Manual

# socket_recv

Receives data from a connected socket

### Description

int socket_recv ( resource `$socket` , string `&$buf` , int `$len` , int `$flags` )

The socket_recv function receives `len` bytes of data in `buf` 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.

`buf` 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 `buf`.

### Parameters

`socket`

  The `socket` must be a socket resource previously created by socket_create().

`buf`

  The data received will be fetched to the variable specified with `buf`. If an error occurs, if the connection is reset, or if no data is available, `buf` will be set to `NULL`.

`len`

  Up to `len` 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 `len` 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.

### 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.