Rapid Web Applications with TurboGears: Using Python to Create Ajax-Powered Sites

Chapter 17.6.1. Validation Errors

Every method decorated by validate() requires a corresponding error handler. The most straightforward way to do so is to declare a function an error handler for a given method via the error_handler() decorator:

@validate(form=my_form)
@error_handler(my_eh)
def register(self, name=None, age=None, email=None):

The function declared as an error handler can have an arbitrary signature, but you might want to declare a parameter tg_errors wherein a mapping of argument names to errors will be passed. If the same error handler is used for multiple methods, an argument tg_source mapped to the method that triggered the error can prove useful.

Other parameters of interest are any named the same as arguments being validated, ...