What are best practices for handling file uploads and form submissions in PHP to ensure data integrity and security?

When handling file uploads and form submissions in PHP, it is essential to validate and sanitize user input to prevent security vulnerabilities such as SQL injection and cross-site scripting attacks. Additionally, it is crucial to set appropriate file upload limits and restrict file types to prevent malicious uploads. 

// Validate and sanitize user input
$username = filter_var($_POST['username'], FILTER_SANITIZE_STRING);
$email = filter_var($_POST['email'], FILTER_VALIDATE_EMAIL);

// Set file upload limits and restrict file types
$allowed_file_types = array('jpg', 'jpeg', 'png');
$max_file_size = 2 * 1024 * 1024; // 2MB

if ($_FILES['file']['size'] > $max_file_size || !in_array(pathinfo($_FILES['file']['name'], PATHINFO_EXTENSION), $allowed_file_types)) {
    // Handle error
} else {
    // Process file upload
}

Keywords

file uploads form submissions data integrity security PHP functions

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