===================================== Writing your first Django app, part 2 ===================================== By Adrian Holovaty This tutorial begins where `Tutorial 1`_ left off. We're continuing the Web-poll application and will focus on Django's automatically-generated admin site. .. _Tutorial 1: http://www.djangoproject.com/documentation/tutorial1/ .. admonition:: Philosophy Generating admin sites for your staff or clients to add, change and delete content is tedious work that doesn't require much creativity. For that reason, Django entirely automates creation of admin interfaces for models. Django was written in a newsroom environment, with a very clear separation between "content publishers" and the "public" site. Site managers use the system to add news stories, events, sports scores, etc., and that content is displayed on the public site. Django solves the problem of creating a unified interface for site administrators to edit content. The admin isn't necessarily intended to be used by site visitors; it's for site managers. Activate the admin site ======================= The Django admin site is not activated by default -- it's an opt-in thing. To activate the admin site for your installation, do these three things: * Add ``"django.contrib.admin"`` to your ``INSTALLED_APPS`` setting. * Run the command ``python manage.py install admin``. This will create an extra database table that the admin needs. * Edit your ``myproject/urls.py`` file and uncomment the line below "Uncomment this for admin:". This file is a URLconf; we'll dig into URLconfs in the next tutorial. For now, all you need to know is that it maps URL roots to applications. Create a user account ===================== Run the following command to create a superuser account for your admin site:: python manage.py createsuperuser The script will prompt you for a username, e-mail address and password (twice). Start the development server ============================ Let's start the development server and explore the admin site. Recall from Tutorial 1 that you start the development server like so:: python manage.py runserver Now, open a Web browser and go to "/admin/" on your local domain -- e.g., http://127.0.0.1:8000/admin/. You should see the admin's login screen: .. image:: http://media.djangoproject.com/img/doc/tutorial/admin01.png :alt: Django admin login screen Enter the admin site ==================== Now, try logging in. You should see the Django admin index page: .. image:: http://media.djangoproject.com/img/doc/tutorial/admin02t.png :alt: Django admin index page :target: http://media.djangoproject.com/img/doc/tutorial/admin02.png By default, you should see two types of editable content: groups and users. These are core features Django ships with by default. .. _"I can't log in" questions: http://www.djangoproject.com/documentation/faq/#the-admin-site Make the poll app modifiable in the admin ========================================= But where's our poll app? It's not displayed on the admin index page. Just one thing to do: We need to specify in the ``Poll`` model that ``Poll`` objects have an admin interface. Edit the ``myproject/polls/models/polls.py`` file and make the following change to add an inner ``META`` class with an ``admin`` attribute:: class Poll(meta.Model): # ... class META: admin = meta.Admin() The ``class META`` contains all `non-field metadata`_ about this model. Now reload the Django admin page to see your changes. Note that you don't have to restart the development server -- it auto-reloads code. .. _non-field metadata: http://www.djangoproject.com/documentation/model_api/#meta-options Explore the free admin functionality ==================================== Now that ``Poll`` has the ``admin`` attribute, Django knows that it should be displayed on the admin index page: .. image:: http://media.djangoproject.com/img/doc/tutorial/admin03t.png :alt: Django admin index page, now with polls displayed :target: http://media.djangoproject.com/img/doc/tutorial/admin03.png Click "Polls." Now you're at the "change list" page for polls. This page displays all the polls in the database and lets you choose one to change it. There's the "What's up?" poll we created in the first tutorial: .. image:: http://media.djangoproject.com/img/doc/tutorial/admin04t.png :alt: Polls change list page :target: http://media.djangoproject.com/img/doc/tutorial/admin04.png Click the "What's up?" poll to edit it: .. image:: http://media.djangoproject.com/img/doc/tutorial/admin05t.png :alt: Editing form for poll object :target: http://media.djangoproject.com/img/doc/tutorial/admin05.png Things to note here: * The form is automatically generated from the Poll model. * The different model field types (``meta.DateTimeField``, ``meta.CharField``) correspond to the appropriate HTML input widget. Each type of field knows how to display itself in the Django admin. * Each ``DateTimeField`` gets free JavaScript shortcuts. Dates get a "Today" shortcut and calendar popup, and times get a "Now" shortcut and a convenient popup that lists commonly entered times. The bottom part of the page gives you a couple of options: * Save -- Saves changes and returns to the change-list page for this type of object. * Save and continue editing -- Saves changes and reloads the admin page for this object. * Save and add another -- Saves changes and loads a new, blank form for this type of object. * Delete -- Displays a delete confirmation page. Change the "Date published" by clicking the "Today" and "Now" shortcuts. Then click "Save and continue editing." Then click "History" in the upper right. You'll see a page listing all changes made to this object via the Django admin, with the timestamp and username of the person who made the change: .. image:: http://media.djangoproject.com/img/doc/tutorial/admin06t.png :alt: History page for poll object :target: http://media.djangoproject.com/img/doc/tutorial/admin06.png Customize the admin form ======================== Take a few minutes to marvel at all the code you didn't have to write. Let's customize this a bit. We can reorder the fields by explicitly adding a ``fields`` parameter to ``meta.Admin``:: admin = meta.Admin( fields = ( (None, {'fields': ('pub_date', 'question')}), ), ) That made the "Publication date" show up first instead of second: .. image:: http://media.djangoproject.com/img/doc/tutorial/admin07.png :alt: Fields have been reordered This isn't impressive with only two fields, but for admin forms with dozens of fields, choosing an intuitive order is an important usability detail. And speaking of forms with dozens of fields, you might want to split the form up into fieldsets:: admin = meta.Admin( fields = ( (None, {'fields': ('question',)}), ('Date information', {'fields': ('pub_date',)}), ), ) The first element of each tuple in ``fields`` is the title of the fieldset. Here's what our form looks like now: .. image:: http://media.djangoproject.com/img/doc/tutorial/admin08t.png :alt: Form has fieldsets now :target: http://media.djangoproject.com/img/doc/tutorial/admin08.png You can assign arbitrary HTML classes to each fieldset. Django provides a ``"collapse"`` class that displays a particular fieldset initially collapsed. This is useful when you have a long form that contains a number of fields that aren't commonly used:: admin = meta.Admin( fields = ( (None, {'fields': ('question',)}), ('Date information', {'fields': ('pub_date',), 'classes': 'collapse'}), ), ) .. image:: http://media.djangoproject.com/img/doc/tutorial/admin09.png :alt: Fieldset is initially collapsed Adding related objects ====================== OK, we have our Poll admin page. But a ``Poll`` has multiple ``Choices``, and the admin page doesn't display choices. Yet. There are two ways to solve this problem. The first is to give the ``Choice`` model its own ``admin`` attribute, just as we did with ``Poll``. Here's what that would look like:: class Choice(meta.Model): # ... class META: admin = meta.Admin() Now "Choices" is an available option in the Django admin. The "Add choice" form looks like this: .. image:: http://media.djangoproject.com/img/doc/tutorial/admin10.png :alt: Choice admin page In that form, the "Poll" field is a select box containing every poll in the database. Django knows that a ``ForeignKey`` should be represented in the admin as a ``