What are the limitations and considerations when using fopen or fsockopen to read content from external websites in PHP?

When using fopen or fsockopen to read content from external websites in PHP, there are limitations and considerations such as potential security risks, network latency, and error handling. It is important to validate and sanitize user input to prevent security vulnerabilities. Additionally, handling timeouts and errors gracefully is crucial to ensure the reliability of the script.

$url = "https://www.example.com";

// Open a connection to the external website using fopen
$handle = fopen($url, "r");

if ($handle) {
    // Read content from the external website
    while (!feof($handle)) {
        echo fgets($handle, 4096);
    }
    
    // Close the connection
    fclose($handle);
} else {
    // Handle connection errors
    echo "Error opening the connection to the external website.";
}