Chaining $_POST filters
Proper filtering and validation is a common problem when processing data submitted by users from an online form. It is arguably also the number one security vulnerability for a website. Furthermore, it can be quite awkward to have the filters and validators scattered all over the application. A chaining mechanism would resolve these issues neatly, and would also allow you to exert control over the order in which the filters and validators are processed.
How to do it...
There is a little-known PHP function,
filter_input_array(), that, at first glance, seems well suited for this task. Looking more deeply into its functionality, however, it soon becomes apparent that this function was designed in the early days, and is not up to modern requirements for protection against attack and flexibility. Accordingly, we will instead present a much more flexible mechanism based on an array of callbacks performing filtering and validation.Note
The difference between filtering and validation...
