---
title: "Form handling with class-based views"
version: 3.0
locale: es
source: https://docs.djangoproject.com/es/3.0/topics/class-based-views/generic-editing/
canonical: https://djangodocs.dev/es/3.0/topics/class-based-views/generic-editing/
---
# Form handling with class-based views

Form processing generally has 3 paths:

- Initial GET (blank or prepopulated form)
- POST with invalid data (typically redisplay form with errors)
- POST with valid data (process the data and typically redirect)

Implementing this yourself often results in a lot of repeated boilerplate code
(see [Using a form in a view](/es/3.0/topics/forms/#using-a-form-in-a-view)). To help avoid
this, Django provides a collection of generic class-based views for form
processing.

## Basic forms

Given a contact form:

*forms.py*

```python
from django import forms

class ContactForm(forms.Form):
    name = forms.CharField()
    message = forms.CharField(widget=forms.Textarea)

    def send_email(self):
        # send email using the self.cleaned_data dictionary
        pass
```

The view can be constructed using a `FormView`:

*views.py*

```python
from myapp.forms import ContactForm
from django.views.generic.edit import FormView

class ContactView(FormView):
    template_name = 'contact.html'
    form_class = ContactForm
    success_url = '/thanks/'

    def form_valid(self, form):
        # This method is called when valid form data has been POSTed.
        # It should return an HttpResponse.
        form.send_email()
        return super().form_valid(form)
```

Notes:

- FormView inherits
  [`TemplateResponseMixin`](/es/3.0/ref/class-based-views/mixins-simple/#django.views.generic.base.TemplateResponseMixin) so
  [`template_name`](/es/3.0/ref/class-based-views/mixins-simple/#django.views.generic.base.TemplateResponseMixin.template_name)
  can be used here.
- The default implementation for
  [`form_valid()`](/es/3.0/ref/class-based-views/mixins-editing/#django.views.generic.edit.FormMixin.form_valid) simply
  redirects to the [`success_url`](/es/3.0/ref/class-based-views/mixins-editing/#django.views.generic.edit.FormMixin.success_url).

## Model forms

Generic views really shine when working with models.  These generic
views will automatically create a [`ModelForm`](/es/3.0/topics/forms/modelforms/#django.forms.ModelForm), so long as
they can work out which model class to use:

- If the [`model`](/es/3.0/ref/class-based-views/mixins-editing/#django.views.generic.edit.ModelFormMixin.model) attribute is
  given, that model class will be used.
- If [`get_object()`](/es/3.0/ref/class-based-views/mixins-single-object/#django.views.generic.detail.SingleObjectMixin.get_object)
  returns an object, the class of that object will be used.
- If a [`queryset`](/es/3.0/ref/class-based-views/mixins-single-object/#django.views.generic.detail.SingleObjectMixin.queryset) is
  given, the model for that queryset will be used.

Model form views provide a
[`form_valid()`](/es/3.0/ref/class-based-views/mixins-editing/#django.views.generic.edit.ModelFormMixin.form_valid) implementation
that saves the model automatically.  You can override this if you have any
special requirements; see below for examples.

You don’t even need to provide a `success_url` for
[`CreateView`](/es/3.0/ref/class-based-views/generic-editing/#django.views.generic.edit.CreateView) or
[`UpdateView`](/es/3.0/ref/class-based-views/generic-editing/#django.views.generic.edit.UpdateView) \- they will use
[`get_absolute_url()`](/es/3.0/ref/models/instances/#django.db.models.Model.get_absolute_url) on the model object if available.

If you want to use a custom [`ModelForm`](/es/3.0/topics/forms/modelforms/#django.forms.ModelForm) (for instance to
add extra validation), set
[`form_class`](/es/3.0/ref/class-based-views/mixins-editing/#django.views.generic.edit.FormMixin.form_class) on your view.

> **Note**
>
> When specifying a custom form class, you must still specify the model,
> even though the [`form_class`](/es/3.0/ref/class-based-views/mixins-editing/#django.views.generic.edit.FormMixin.form_class) may
> be a [`ModelForm`](/es/3.0/topics/forms/modelforms/#django.forms.ModelForm).

First we need to add [`get_absolute_url()`](/es/3.0/ref/models/instances/#django.db.models.Model.get_absolute_url) to our
`Author` class:

*models.py*

```python
from django.db import models
from django.urls import reverse

class Author(models.Model):
    name = models.CharField(max_length=200)

    def get_absolute_url(self):
        return reverse('author-detail', kwargs={'pk': self.pk})
```

Then we can use [`CreateView`](/es/3.0/ref/class-based-views/flattened-index/#CreateView) and friends to do the actual
work. Notice how we’re just configuring the generic class-based views
here; we don’t have to write any logic ourselves:

*views.py*

```python
from django.urls import reverse_lazy
from django.views.generic.edit import CreateView, DeleteView, UpdateView
from myapp.models import Author

class AuthorCreate(CreateView):
    model = Author
    fields = ['name']

class AuthorUpdate(UpdateView):
    model = Author
    fields = ['name']

class AuthorDelete(DeleteView):
    model = Author
    success_url = reverse_lazy('author-list')
```

> **Note**
>
> We have to use [`reverse_lazy()`](/es/3.0/ref/urlresolvers/#django.urls.reverse_lazy) instead of
> `reverse()`, as the urls are not loaded when the file is imported.

The `fields` attribute works the same way as the `fields` attribute on the
inner `Meta` class on [`ModelForm`](/es/3.0/topics/forms/modelforms/#django.forms.ModelForm). Unless you define the
form class in another way, the attribute is required and the view will raise
an [`ImproperlyConfigured`](/es/3.0/ref/exceptions/#django.core.exceptions.ImproperlyConfigured) exception if it’s not.

If you specify both the [`fields`](/es/3.0/ref/class-based-views/mixins-editing/#django.views.generic.edit.ModelFormMixin.fields)
and [`form_class`](/es/3.0/ref/class-based-views/mixins-editing/#django.views.generic.edit.FormMixin.form_class) attributes, an
[`ImproperlyConfigured`](/es/3.0/ref/exceptions/#django.core.exceptions.ImproperlyConfigured) exception will be raised.

Finally, we hook these new views into the URLconf:

*urls.py*

```python
from django.urls import path
from myapp.views import AuthorCreate, AuthorDelete, AuthorUpdate

urlpatterns = [
    # ...
    path('author/add/', AuthorCreate.as_view(), name='author-add'),
    path('author/<int:pk>/', AuthorUpdate.as_view(), name='author-update'),
    path('author/<int:pk>/delete/', AuthorDelete.as_view(), name='author-delete'),
]
```

> **Note**
>
> These views inherit
> [`SingleObjectTemplateResponseMixin`](/es/3.0/ref/class-based-views/mixins-single-object/#django.views.generic.detail.SingleObjectTemplateResponseMixin)
> which uses
> [`template_name_suffix`](/es/3.0/ref/class-based-views/mixins-single-object/#django.views.generic.detail.SingleObjectTemplateResponseMixin.template_name_suffix)
> to construct the
> [`template_name`](/es/3.0/ref/class-based-views/mixins-simple/#django.views.generic.base.TemplateResponseMixin.template_name)
> based on the model.
>
> In this example:
>
> - [`CreateView`](/es/3.0/ref/class-based-views/flattened-index/#CreateView) and [`UpdateView`](/es/3.0/ref/class-based-views/flattened-index/#UpdateView) use `myapp/author_form.html`
> - [`DeleteView`](/es/3.0/ref/class-based-views/flattened-index/#DeleteView) uses `myapp/author_confirm_delete.html`
>
> If you wish to have separate templates for [`CreateView`](/es/3.0/ref/class-based-views/flattened-index/#CreateView) and
> [`UpdateView`](/es/3.0/ref/class-based-views/flattened-index/#UpdateView), you can set either
> [`template_name`](/es/3.0/ref/class-based-views/mixins-simple/#django.views.generic.base.TemplateResponseMixin.template_name) or
> [`template_name_suffix`](/es/3.0/ref/class-based-views/mixins-single-object/#django.views.generic.detail.SingleObjectTemplateResponseMixin.template_name_suffix)
> on your view class.

## Models and `request.user`

To track the user that created an object using a [`CreateView`](/es/3.0/ref/class-based-views/flattened-index/#CreateView),
you can use a custom [`ModelForm`](/es/3.0/topics/forms/modelforms/#django.forms.ModelForm) to do this. First, add
the foreign key relation to the model:

*models.py*

```python
from django.contrib.auth.models import User
from django.db import models

class Author(models.Model):
    name = models.CharField(max_length=200)
    created_by = models.ForeignKey(User, on_delete=models.CASCADE)

    # ...
```

In the view, ensure that you don’t include `created_by` in the list of fields
to edit, and override
[`form_valid()`](/es/3.0/ref/class-based-views/mixins-editing/#django.views.generic.edit.ModelFormMixin.form_valid) to add the user:

*views.py*

```python
from django.contrib.auth.mixins import LoginRequiredMixin
from django.views.generic.edit import CreateView
from myapp.models import Author

class AuthorCreate(LoginRequiredMixin, CreateView):
    model = Author
    fields = ['name']

    def form_valid(self, form):
        form.instance.created_by = self.request.user
        return super().form_valid(form)
```

[`LoginRequiredMixin`](/es/3.0/topics/auth/default/#django.contrib.auth.mixins.LoginRequiredMixin) prevents users who
aren’t logged in from accessing the form. If you omit that, you’ll need to
handle unauthorized users in [`form_valid()`](/es/3.0/ref/class-based-views/mixins-editing/#django.views.generic.edit.ModelFormMixin.form_valid).

## AJAX example

Here is an example showing how you might go about implementing a form that
works for AJAX requests as well as “normal” form POSTs:

```
from django.http import JsonResponse
from django.views.generic.edit import CreateView
from myapp.models import Author

class AjaxableResponseMixin:
    """
    Mixin to add AJAX support to a form.
    Must be used with an object-based FormView (e.g. CreateView)
    """
    def form_invalid(self, form):
        response = super().form_invalid(form)
        if self.request.is_ajax():
            return JsonResponse(form.errors, status=400)
        else:
            return response

    def form_valid(self, form):
        # We make sure to call the parent's form_valid() method because
        # it might do some processing (in the case of CreateView, it will
        # call form.save() for example).
        response = super().form_valid(form)
        if self.request.is_ajax():
            data = {
                'pk': self.object.pk,
            }
            return JsonResponse(data)
        else:
            return response

class AuthorCreate(AjaxableResponseMixin, CreateView):
    model = Author
    fields = ['name']
```