socket_recv

    (PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

    socket_recv — Receives data from a connected socket

    Description

    socket_recv(
        Socket$socket,
        ?string&$data,
        int$length,
        int$flags
    ): int|false

    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 to null.

    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
    FlagDescription
    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

    VersionDescription
    8.0.0socket 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";


    $service_port = getservbyname('www', 'tcp');


    $address = gethostbyname('www.example.com');


    $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.
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