Install libparams-callbackrequest-perl by entering the following commands in the terminal:
sudo apt update sudo apt install libparams-callbackrequest-perl
handler for functional and object-oriented callbacks in Perl
Params::CallbackRequest provides functional and object-oriented callbacks to method and function parameters. Callbacks may be either code references provided to the new() constructor, or methods defined in subclasses of Params::Callback. Callbacks are triggered either for every call to the Params::CallbackRequest request() method, or by specially named keys in the parameters to request(). . The idea behind this module is to provide a sort of plugin architecture for Perl templating systems. Callbacks are triggered by the contents of a request to the Perl templating server, before the templating system itself executes. This approach allows you to carry out logical processing of data submitted from a form, to affect the contents of the request parameters before they're passed to the templating system for processing, and even to redirect or abort the request before the templating system handles it.