PHP Network

Key Network Functions

file_get_contents($url);

fsockopen($host, $port);

mail($to, $subject, $message);

gethostbyname($hostname);

🔹 Fetching URL Content

Use file_get_contents() to retrieve data from remote URLs. This is the simplest way to make HTTP GET requests and fetch web content or API responses.

<?php
// Fetch content from a URL
$url = "https://jsonplaceholder.typicode.com/posts/1";
$response = file_get_contents($url);

if ($response !== FALSE) {
    $data = json_decode($response, true);
    echo "Title: " . $data['title'];
} else {
    echo "Failed to fetch data";
}
?>

🔹 Using cURL for Advanced Requests

cURL provides more control over HTTP requests with support for headers, POST data, authentication, and various protocols. It's ideal for complex API interactions.

<?php
// Initialize cURL session
$ch = curl_init();

// Set cURL options
curl_setopt($ch, CURLOPT_URL, "https://api.example.com/data");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json'));

// Execute request
$response = curl_exec($ch);
$httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

// Close cURL session
curl_close($ch);

echo "HTTP Code: " . $httpCode;
?>

🔹 POST Request with cURL

Send data to remote servers using POST requests. This is commonly used for submitting forms, uploading data, or interacting with RESTful APIs.

<?php
$ch = curl_init();
$data = array('name' => 'John', 'email' => '[email protected]');

curl_setopt($ch, CURLOPT_URL, "https://api.example.com/users");
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json'));

$response = curl_exec($ch);
curl_close($ch);

echo "User created successfully";
?>

🔹 Socket Connection

Create low-level network connections using sockets. Sockets allow direct communication with servers using TCP/IP protocols for custom network applications.

<?php
// Open socket connection
$socket = fsockopen("www.example.com", 80, $errno, $errstr, 30);

if (!$socket) {
    echo "Error: $errstr ($errno)";
} else {
    // Send HTTP request
    fwrite($socket, "GET / HTTP/1.1\r\nHost: www.example.com\r\n\r\n");
    
    // Read response (first line)
    $response = fgets($socket);
    echo "Response: " . $response;
    
    fclose($socket);
}
?>

🔹 DNS Lookup

Resolve domain names to IP addresses using DNS functions. This helps you find the server address behind a domain name or verify DNS configuration.

<?php
// Get IP address from hostname
$hostname = "www.google.com";
$ip = gethostbyname($hostname);

echo "Hostname: " . $hostname . "<br>";
echo "IP Address: " . $ip;

// Get hostname from IP
$host = gethostbyaddr($ip);
echo "<br>Reverse lookup: " . $host;
?>

🔹 Checking URL Headers

Retrieve HTTP headers from a URL without downloading the entire content. This is useful for checking if a resource exists or getting metadata.

<?php
$url = "https://www.example.com";
$headers = get_headers($url, 1);

echo "Status: " . $headers[0] . "<br>";
echo "Content-Type: " . $headers['Content-Type'] . "<br>";
echo "Server: " . $headers['Server'];
?>