old web2py blog

Consider this form:

test():
    form=FORM(LABEL("Username:",INPUT(_name="user_name",
              requires=IS_NOT_EMPTY(error_message="test"))),
              INPUT(_type='submit'))

This is the general approach to form validation:

if form.accepts(request.vars,session,formname='myform'):
    #option 1
elif form.errors:
    #option 2

In option 2 you can:

a) rewrite error messages:

if form.errors.user_name: form.errors.user_name='oops!'

b) copy error messages in a dictionary

import copy
myerrors=copy.copy(form.errors)

c) clear errors so that they are not displayed:

form.errors.clear()

Moreover

form.components[0] is the LABEL object

form.components[0].components[0] is "Username:"

form.components[0].components[1] is the INPUT object

form.components[0].components[1].attributes['requires'] is the IS_NOT_EMPTY object.

Technically you can do:

form.components[0].components[1].attributes['requires'].error_message="oops!"

but this is not a good idea since it easy to get it wrong.