Documented the always_test attribute for validator functions.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3792 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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Malcolm Tredinnick 2006-09-22 12:46:35 +00:00
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@ -481,6 +481,33 @@ the data being validated.
Also, because consistency in user interfaces is important, we strongly urge you
to put punctuation at the end of your validation messages.
When Are Validators Called?
---------------------------
After a form has been submitted, Django first checks to see that all the
required fields are present and non-empty. For each field that passes that
test *and if the form submission contained data* for that field, all the
validators for that field are called in turn. The emphasised portion in the
last sentence is important: if a form field is not submitted (because it
contains no data -- which is normal HTML behaviour), the validators are not
run against the field.
This feature is particularly important for models using
``models.BooleanField`` or custom manipulators using things like
``forms.CheckBoxField``. If the checkbox is not selected, it will not
contribute to the form submission.
If you would like your validator to *always* run, regardless of whether the
field it is attached to contains any data, set the ``always_test`` attribute
on the validator function. For example::
def my_custom_validator(field_data, all_data):
# ...
my_custom_validator.always_test = True
This validator will always be executed for any field it is attached to.
Ready-made Validators
---------------------