Validating and cleaning data
=============================

Processors
----------

Before validation, any processing functions are run. These allow you do simple cleaning operations (eg calling `strip` on string values) before any validation rules are checked.
Processors can be configured by setting :attr:`~morf.fields.Field.processors`:

.. code:: python

    class MyForm(Form):

        email = fields.Str(processors=[lambda s: s.lower().strip()])


Validators
----------

Morf includes various common validator functions that can be
configured by setting :attr:`~morf.fields.Field.validators`:

.. code:: python

    from morf import Form, fields, validators

    class MyForm(Form):

        email = fields.Str(validators=[validators.is_email()])
        message = fields.Str(validators=[validators.minlen(10)])


Refer to :mod:`~morf.validators` for the list of built-in validation functions.


Ad-hoc validation functions
---------------------------

:meth:`~morf.form.validates` lets you create ad-hoc validation functions:


.. code:: python

    from morf import Form
    from morf import validates

    class MyForm(Form):

        number1 = fields.Int()
        number2 = fields.Int()

        @validates(number1)
        def check_first_number_is_even(self, n1):
            if n1 % 2 != 0:
                self.fail("Even numbers only!")

        @validates(number1, number2)
        def check_second_number_is_multiple_of_first(self, n1, n2):
            if n2 % n1 != 0
                self.fail("Enter a multiple of the first number")

        @cleans(word)
        def clean_word(self, word):
            return word.lower()


:meth:`~morf.form.cleans` works in a similar way for data cleaning functions,
which are expected to return the cleaned data:

.. code:: python

    from morf import Form
    from morf import cleans

    class MyForm(Form):

        word = fields.Str()

        @cleans(word)
        def clean_word(self, word):
            return word.lower()


A validator or cleaner may also act on the whole form object:

.. code:: python


        @cleans
        def clean_everything(self):
            self.data['word'] = self.data['word'].lower()



Validators reference
---------------------


.. automodule:: morf.validators
    :members: