What are the best practices for handling external URLs and including them in PHP scripts for automatic page loading?

When including external URLs in PHP scripts for automatic page loading, it is important to ensure the URLs are sanitized to prevent security vulnerabilities such as cross-site scripting (XSS) attacks. One way to do this is by using the filter_var() function with the FILTER_VALIDATE_URL filter to validate the URL before including it in the script. Additionally, it is recommended to set up proper error handling to gracefully handle any exceptions that may occur when loading external content.

// Example of handling external URLs in PHP scripts

// Define the external URL
$external_url = "https://www.example.com";

// Validate the URL using filter_var
if (filter_var($external_url, FILTER_VALIDATE_URL)) {
    // Load the external content
    $external_content = file_get_contents($external_url);
    
    // Output the content
    echo $external_content;
} else {
    // Handle invalid URL
    echo "Invalid URL provided";
}