What best practices should be followed when working with file uploads and email attachments in PHP?

When working with file uploads and email attachments in PHP, it is important to validate the file type, size, and content before processing or sending it. This helps prevent security vulnerabilities such as malicious file uploads or attachments. Additionally, always sanitize user input to prevent code injection attacks. 

// Validate file type, size, and content before processing
if ($_FILES['file']['type'] != 'image/jpeg' || $_FILES['file']['size'] > 5000000) {
    // Handle error or reject file
}

// Sanitize user input before using it
$email = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL);

// Process file upload or email attachment
// Code to handle file upload or email attachment

Keywords

file uploads email attachments PHP security MIME types

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