Master PHP’s fsockopen(): Open Network Connections & Fetch Remote Content

Function Overview

The fsockopen() function in PHP opens a network connection using the TCP/IP protocol, allowing communication with remote servers to send requests and receive responses.

Syntax

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

Parameters

$hostname

: Target host address (IP or domain name). $port: Optional port number; default -1 uses the service’s default port. &$errno: Variable that receives an error code on failure. &$errstr: Variable that receives an error message on failure. $timeout: Optional timeout in seconds; defaults to the value of ini_get("default_socket_timeout").

Return Value

On success, returns a resource handle containing connection information, which can be used by other functions. On failure, returns false.

Usage Example

The following script demonstrates how to use fsockopen() to connect to a remote web server, send a simple HTTP GET request, and output the response.

<?php
// Define target server and port
$hostname = 'www.example.com';
$port = 80;

// Open a network connection
$fp = fsockopen($hostname, $port, $errno, $errstr, 10);

if (!$fp) {
    echo "Connection failed: $errno - $errstr";
    exit;
}

// Build HTTP request headers
$request = "GET / HTTP/1.1
";
$request .= "Host: $hostname
";
$request .= "Connection: close

";

// Send request
fwrite($fp, $request);

// Read and output response
while (!feof($fp)) {
    echo fgets($fp, 128);
}

// Close connection
fclose($fp);
?>

This code creates a connection to www.example.com on port 80, sends an HTTP GET request, and continuously reads the server’s response until the connection closes.

SSL Connections

To open an SSL‑encrypted connection, prefix the hostname with ssl:// and use the appropriate port (typically 443).