What are the security considerations when working with external URLs in PHP scripts?

When working with external URLs in PHP scripts, it is important to validate and sanitize the input to prevent security vulnerabilities such as SQL injection, cross-site scripting (XSS), and remote code execution. It is also recommended to use secure connections (HTTPS) when communicating with external URLs to protect sensitive data. 

// Example of validating and sanitizing an external URL in PHP
$externalUrl = filter_var($_GET['url'], FILTER_VALIDATE_URL);
if ($externalUrl) {
    // Perform actions with the validated URL
} else {
    // Handle invalid URL input
}

Keywords

XSS CSRF input validation URL encoding secure coding practices

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