Validating data php
White list validation is appropriate for all input fields provided by the user.
White list validation involves defining exactly what IS authorized, and by definition, everything else is not authorized.
We will start small, and ignore the validation in the first step.
Ideally, we can initialize an object through its constructor: The constructor's responsibility is to initialize an object into a sane state.
Developing regular expressions can be complicated, and is well beyond the scope of this cheat sheet.
There are lots of resources on the internet about how to write regular expressions, including: and the OWASP Validation Regex Repository.
As the local-part of email addresses are, in fact - case sensitive, it is important to store and compare email addresses correctly.If the input field comes from a fixed set of options, like a drop down list or radio buttons, then the input needs to match exactly one of the values offered to the user in the first place.The most difficult fields to validate are so called 'free text' fields, like blog entries.These are covered in output encoding and related cheat sheets.
It is always recommended to prevent attacks as early as possible in the processing of the user’s (attacker's) request.
It is very difficult to validate rich content submitted by a user.