Forms¶

is_core.forms contains helpers for forms rutines. The most interesting class is SmartForm.

SmartForm¶

Imagine you need to dynamically change behaviour of your form fields, e.g. make a field required when some condition holds. In pure Django, you would override the __init__ method and change the field attributes there. However, that’s pretty uncomfortable as you need to explicitly call super. More importantly, the __init__ method tends to grow and become unreadable for complex forms. With SmartForm, you can define _init_fields method instead and put your field-related logic there. For example:

from is_core.forms import SmartForm

class MyForm(SmartForm):

    def _init_fields(self):

        for field in self.fields:
            if field.name == 'foo':
                # do logic for foo
            elif field.name == 'bar':
                # do logic for bar

Even more readable way is to define the _init_{field_name} method for the individual fields thus removing the clumsy for cycle and if-elif-else:

from is_core.forms import SmartForm

class MyForm(SmartForm):

    def _init_foo(self, field):
        field.required = False
        if self._my_secret_condition():
            # do logic for foo

    def _init_bar(self, field):
        # do logic for bar

Yay! It’s pretty, isn’t it?

SmartForm contains helper methods that are called when an instance is created in a following order:

_pre_init_fields
_init_{field_name} methods
_init_fields

SmartForm._pre_init_fields(self)¶

This method is called when a form is created (after super __init__ method and before _init_{field_name} methods). It makes fields from base_required_fields attribute required.

SmartForm._init_{field_name}(self, field)

This method is called when a form has foo field and it is created (after super __init__ method and after _pre_init_fields method). You can modify the field’s attributes here. There is no need to return the field as it modifies the internal state of the passed field.:

from is_core.forms import SmartForm

class MyForm(SmartForm):

    def _init_foo(field):
        # put logic here

SmartForm._init_fields(self)¶

This method is called when a form is created (after super __init__ method and after _init_{field_name} methods:

from is_core.forms import SmartForm

class MyForm(SmartForm):

    def _init_fields(self):
        # put logic here

SmartForm.changed_data¶

This attribute contains changed data as a dict. More details.

SmartFormMixin¶

In case that you have your own form you can use this mixin to get same functionality as SmartForm.

smartform_factory(request, form, readonly_fields=None, required_fields=None,
exclude=None, formreadonlyfield_callback=None, readonly=False)

A wrapper factory for SmartForm.