From c012d6ccf1b4d4b73c0e2633d14e70fe8f04d252 Mon Sep 17 00:00:00 2001 From: Adrian Holovaty Date: Sun, 17 Jul 2005 00:54:15 +0000 Subject: [PATCH] Added first part of docs/tutorial02.txt git-svn-id: http://code.djangoproject.com/svn/django/trunk@129 bcc190cf-cafb-0310-a4f2-bffc1f526a37 --- docs/tutorial02.txt | 258 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 258 insertions(+) create mode 100644 docs/tutorial02.txt diff --git a/docs/tutorial02.txt b/docs/tutorial02.txt new file mode 100644 index 0000000000..85020accc2 --- /dev/null +++ b/docs/tutorial02.txt @@ -0,0 +1,258 @@ +===================================== +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/ + +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. + +Expose the admin media files +============================ + +Django's admin is intended to be fully functional and good looking. For that +reason, Django ships with admin media files -- CSS, JavaScript and images -- +that comprise the admin's design. To set up a Django admin instance, the first +thing to do is put those media files online somewhere. + +(Note: Although Django ships with a default design for its admin site, you can +change it however you'd like. The admin uses Django's own template system and +is powered -- surprise, surprise -- by Django itself, so it is completely +customizable.) + +The files are in the ``media`` directory of the Django distribution. To +"activate" them, copy that directory under a Web document root somewhere, so +that you can access them via the Web. + +Be careful not to put your Python source code under the Web document root. Just +do the media files. + +Then, tell Django where you put them, via ``ADMIN_MEDIA_PREFIX`` in the +``myproject.settings.admin`` settings file. Examples:: + + # You can leave off the domain if they're on the same domain as your admin + # site will be. + ADMIN_MEDIA_PREFIX = '/adminmedia/' + + # Otherwise, use the fully-qualified domain. + ADMIN_MEDIA_PREFIX = 'http://www.foo.com/adminmedia/' + +Make sure to include a trailing slash. + +Hook into mod_python +==================== + +Now let's take the opportunity to hook Django into Apache/mod_python. Edit your +``httpd.conf`` file and add this:: + + + SetHandler python-program + PythonHandler django.core.handler + SetEnv DJANGO_SETTINGS_MODULE myproject.settings.admin + + +This tells Apache: "Use mod_python for any URL at or under '/admin/', using the +Django mod_python handler." It also passes the value of ``DJANGO_SETTINGS_MODULE``, +so mod_python knows which project to use. Note that we're passing the path to +the ``admin`` settings, not the ``main`` settings. That's because this is the +admin site, which has slightly different settings. + +You can also add directives such as ``PythonAutoReload Off`` for performance. +See the `mod_python documentation`_ for a full list of options. + +When you've done that, restart Apache and go to /admin/ on your domain. You +should see the admin's login screen: + +.. image:: http://media.djangoproject.com/img/doc/tutorial/admin01.png + :alt: Django admin login screen + +.. _mod_python documentation: http://modpython.org/live/current/doc-html/directives.html + +Create a user account +===================== + +We can't log in, though, because we haven't created an admin user account yet. +Drop into the Python interactive interpreter and type this:: + + # The function django.models.auth.users.create_user() creates a new user + # and returns the new auth.User object. + # Don't use 'username' and 'password'. Those are just examples. + >>> from django.models.auth import users + >>> u = users.create_user('username', 'your_email@domain.com', 'password') + + # But we're not done. We need to explicitly set is_staff and is_active to + # allow this user to access the admin. Might as well make it a superuser, + # too. + u.is_staff = True + u.is_active = True + u.is_superuser = True + + # Remember, call the save() method to save changes. + u.save() + +Enter the admin site +==================== + +Now, try logging in. If the login worked, 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 four types of editable content: groups, users, +redirects and flat files. These are core features Django ships with by default. + +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 ``polls.Poll`` model that Poll +objects have an admin interface. Edit the ``myproject/apps/polls/models/polls.py`` +file and make the following change to add an ``admin`` attribute:: + + class Poll(meta.Model): + fields = ( + # ... + ) + admin = meta.Admin( + fields = ( + (None, {'fields': ('question', 'pub_date')}), + ), + ) + +Reload the Django admin index page. Note that you might have to restart Apache, +depending on your Apache settings. Because mod_python saves code in memory for +performance, Python code changes generally aren't reflected until Apache +restarts. One way around this is to set ``MaxRequestsPerChild 1`` in your +httpd.conf to force Apache to reload everything for each request. But don't do +that on a production server, or we'll revoke your Django privileges. + +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. +* ``DateTimeField``s get 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 changelist 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 changing the +order of the field names in the ``admin`` attribute of the model:: + + 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 + +Customize the admin change list +=============================== + +There's much more to come. This document is not finished.