Is ther any alternatives for data validation of user input

Question

Is preg_match() a reliable function to use it on its own to validate input data? just for validation(I am not talking about sanitizating and escaping).

For example: I want to allow only letters and numbers from a user input. To make sure that this happens i will use preg_match("/^[a-zA-Z0-9]*$/",$_POST["input"]) . apart from client side (js) and filter_input() (php) validation is there any other method to validate data?

thanks

EDIT: i meant very reliable method (the best ), I know that there other ways around to validate.

Answer 1

You should use filter_input or filter_var for validation. You can use range of pre-defined validation filters or specify your custom filter with filter callback .