CiviCRM Community Forums (archive)

I'm working on an extension that provides the ability to apply taxes to specific contribution types.

We hacked civiCRM 3.4.x core to achieve this ability and our code works well but I'd like to make it modular and maintainable.   

Using the civix tool, I've sort of got the front end done so the admin can add/apply taxes to specific contribution types. It then adds tax related statements to applicable contribution pages but now I have to roll up my sleeves to do some real work; namely overloading the public function preProcess() that can be found in civicrm/CRM/Contribute/Form/Contribution/Confirm.php and civicrm/CRM/Event/Form/Registration/Confirm.php.

I'd like my extension code to use hook_civicrm_buildForm($formName, $form) test the contribution type and if it's applicable, query my tax tables to see which taxes are applicable, calculate the tax, stuff the values in a civi_tax_invoicing database table that I'll add to the detailed report.

The first thing I need some direction on is how can I overload the preProcess() function.

Once I've got that working, I'll be back looking for direction on overloading the reporting functions. When we hacked core to make this work on 3.x we found that the lions share of the work was involved in the reporting side so I am prepared for some late nights and frustration getting this completed 

Thanks,
Andrew

Hey Lobo,

Thanks for the direction.

I was thinking that I could add my code in the buildform hook but I'm not sure how. With the hack we performed we added the code smack dab in the middle of the preProcess function. Can I declare the function in my extension so that it will take precidence over the OEM function. If so is there some documentation about how the naming convention is handled?

Thanks,
Andrew