How do I validate and sanitize user input in PHP?

Validating and sanitizing user input in PHP is crucial for maintaining security and data integrity in your applications. Here’s how you can effectively validate and sanitize user input.

Validation

Validation ensures that the data is correct and appropriate. For example, checking if an email address is in the correct format.

Sanitization

Sanitization is the process of cleaning the input by removing unwanted characters or scripts. For instance, stripping out HTML tags from user input.

Example Code

<?php // Example of validating an email $email = $_POST['email']; if (filter_var($email, FILTER_VALIDATE_EMAIL)) { echo "Valid email address."; } else { echo "Invalid email address."; } // Example of sanitizing a string $user_input = $_POST['user_input']; $sanitized_input = strip_tags($user_input); echo "Sanitized input: " . $sanitized_input; ?>

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