fsockopen

(PHP 4, PHP 5, PHP 7)

Open Internet or Unix domain socket connection

resource fsockopen ( string $hostname [, int $port = -1 [, int &$errno [, string &$errstr [, float $timeout = ini_get("default_socket_timeout") ]]]] )

Initiates a socket connection to the resource specified by hostname.

PHP supports targets in the Internet and Unix domains as described in List of Supported Socket Transports. A list of supported transports can also be retrieved using stream_get_transports().

The socket will by default be opened in blocking mode. You can switch it to non-blocking mode by using stream_set_blocking().

The function stream_socket_client() is similar but provides a richer set of options, including non-blocking connection and the ability to provide a stream context.

Parameters:

hostname

If OpenSSL support is installed, you may prefix the hostname with either ssl:// or tls:// to use an SSL or TLS client connection over TCP/IP to connect to the remote host.

port

The port number. This can be omitted and skipped with -1 for transports that do not use ports, such as unix://.

errno

If provided, holds the system level error number that occurred in the system-level connect() call.

If the value returned in errno is 0 and the function returned FALSE, it is an indication that the error occurred before the connect() call. This is most likely due to a problem initializing the socket.

errstr

The error message as a string.

timeout

The connection timeout, in seconds.

Note:

If you need to set a timeout for reading/writing data over the socket, use stream_set_timeout(), as the timeout parameter to fsockopen() only applies while connecting the socket.

Returns:

fsockopen() returns a file pointer which may be used together with the other file functions (such as fgets(), fgetss(), fwrite(), fclose(), and feof()). If the call fails, it will return FALSE

Exception:

Throws E_WARNING if hostname is not a valid domain.

Notes:

Depending on the environment, the Unix domain or the optional connect timeout may not be available.

When specifying a numerical IPv6 address (e.g. fe80::1), you must enclose the IP in square brackets—for example, tcp://[fe80::1]:80.

Examples:

fsockopen() Example

<?php
$fp = fsockopen("www.example.com", 80, $errno, $errstr, 30);
if (!$fp) {
    echo "$errstr ($errno)<br />\n";
} else {
    $out = "GET / HTTP/1.1\r\n";
    $out .= "Host: www.example.com\r\n";
    $out .= "Connection: Close\r\n\r\n";
    fwrite($fp, $out);
    while (!feof($fp)) {
        echo fgets($fp, 128);
    }
    fclose($fp);
}
?>

Using UDP connection

The example below shows how to retrieve the day and time from the UDP service "daytime" (port 13) in your own machine.

<?php
$fp = fsockopen("udp://127.0.0.1", 13, $errno, $errstr);
if (!$fp) {
    echo "ERROR: $errno - $errstr<br />\n";
} else {
    fwrite($fp, "\n");
    echo fread($fp, 26);
    fclose($fp);
}
?>