Archive for January, 2009

Antares

posted on January 18th, 2009 by PyromanX in Greg's Pictures on Flickr

PyromanX posted a photo:

Antares

Named after

Named after the Red Supergiant because the case is huge and has red lights.

Named after the Red Supergiant because the case is huge and has red lights.

Antares

posted on January 18th, 2009 by PyromanX in Greg's Pictures on Flickr

PyromanX posted a photo:

Antares

Named after

Named after the Red Supergiant because the case is huge and has red lights.

Named after the Red Supergiant because the case is huge and has red lights.

Antares

posted on January 18th, 2009 by PyromanX in Greg's Pictures on Flickr

PyromanX posted a photo:

Antares

Named after

Named after the Red Supergiant because the case is huge and has red lights.

Named after the Red Supergiant because the case is huge and has red lights.

Antares

posted on January 18th, 2009 by PyromanX in Greg's Pictures on Flickr

PyromanX posted a photo:

Antares

Named after

Named after the Red Supergiant because the case is huge and has red lights.

Named after the Red Supergiant because the case is huge and has red lights.

Antares

posted on January 18th, 2009 by PyromanX in Greg's Pictures on Flickr

PyromanX posted a photo:

Antares

Named after

Named after the Red Supergiant because the case is huge and has red lights.

Named after the Red Supergiant because the case is huge and has red lights.

How to Write Reusable Apps for Pinax and Django

posted on January 15th, 2009 by Greg Allard in Greg's Posts on Code Spatter

Pinax is a collection of reusable django apps that brings together features that are common to many websites. It allows developers to focus on what makes their site unique. Here is an example of adding your own functionality to Pinax. It will also be an example of writing a reusable app since every individual app currently in Pinax can be used separately. Also, I’ve bundled the
example files into a google code project.

My example will be to create a list of books and allow them to be tied to any object using
Django’s ContentType framework. The books could be recommended reading for the members of a tribe (pinax group), a class, or anything in your project and will include title, description, and tags (requires
django-tagging). In another post I’ve shown
how to create template tags to make it easy to show the list of books and a form to add a book. Obviously, there is a lot more that could be done with this app, but I will leave it out of the example to keep it simple.

Starting the App

Create a folder in the apps directory or any place that is on the python path (ex. /path/to/pinax/projects/complete_project/apps/books/) and include these files:

  • __init__.py even though it might be empty, it is required
  • forms.py
  • models.py
  • urls.py
  • views.py

models.py

I will start with creating the model for the project. Below is all of the code I am placing in the file. I’ve added a lot of comments to explain everything that is happening.

#import all of the things we will be using
from django.db                          import models
from tagging.fields                     import TagField
# to help with translation of field names
from django.utils.translation  import ugettext_lazy as _
# to have a generic foreign key for any model
from django.contrib.contenttypes        import generic
# stores model info so this can be applied to any model
from django.contrib.contenttypes.models import ContentType
 
class Book(models.Model):
    """
    The details of a Book
    """
    # fields that describe this book
    name        = models.CharField(_('name'), max_length=48)
    description = models.TextField(_('description'))
 
    # to add to any model
    content_type   = models.ForeignKey(ContentType)
    object_id      = models.PositiveIntegerField()
    content_object = generic.GenericForeignKey('content_type',
        'object_id')
 
    # for the list of tags for this book
    tags        = TagField()
 
    # misc fields
    deleted     = models.BooleanField(default=0)
    created     = models.DateTimeField(auto_now_add=True)
    # so that {{book.get_absolute_url}} outputs the whole url
    @models.permalink
    def get_absolute_url(self):
        return ("book_details", [self.pk])
    # outputs name when printing this object as a string
    def __unicode__(self):
        return self.name

forms.py

Use Django’s ModelForm to create a form for our book model.

from django import forms
from books.models import Book
 
class NewBookForm(forms.ModelForm):
    class Meta:
        model = Book
        exclude = ('deleted', 'content_type',
            'object_id', 'created')

views.py

In this file we create a view to show the details of a book and a view to create a new book for an object.

from django.shortcuts import render_to_response
from django.shortcuts import get_object_or_404
from django.http import HttpResponseRedirect
from django.template import RequestContext
from django.core.urlresolvers import reverse
from django.utils.translation import ugettext_lazy as _
from django.contrib.auth.decorators import login_required
 
from tribes.models import Tribe
from books.models import Book
from django.contrib.contenttypes.models import ContentType
 
@login_required
def new(request, content_type_id, object_id,
            template_name="books/new.html"):
    """
    creates a new book
    """
    from books.forms import NewBookForm
 
    # if a new book was posted
    if request.method == 'POST':
        book_form = NewBookForm(request.POST)
        if book_form.is_valid():
            # create it
            book = book_form.save(commit=False)
            content_type        = \
                ContentType.objects.get(id=content_type_id)
            content_object      = \
                content_type.get_object_for_this_type(
                id=object_id)
            book.content_object = content_object
            book.save()
            request.user.message_set.create(
                message=
                _("Successfully created book '%s'")
                % book.name)
            # send to object page or book page
            try:
                return HttpResponseRedirect(
                    content_object.get_absolute_url()
                )
            except:
                return HttpResponseRedirect(reverse(
                    'book_details', args=(book.id,)))
        # if invalid, it gets displayed below
    else:
        book_form = NewBookForm()
 
    return render_to_response(template_name, {
        'book_form': book_form,
    }, context_instance=RequestContext(request))
 
@login_required
def details(request, book_id,
    template_name="books/details.html"):
    """
    displays details of a book
    """
    book = get_object_or_404(Book, id=book_id)
    return render_to_response(template_name, {
        'book': book,
    }, context_instance=RequestContext(request))

urls.py

To tie our views to some urls, add this to the urls.py file.

from django.conf.urls.defaults import *
from django.conf.urls.defaults import *
 
urlpatterns = patterns('',    
    # new book for object
    url(r'^new/(?P<content_type_id>\d+)/(?P<object_id>\d+)', 
        'books.views.new', name="new_book"),
    # display details of a book
    url(r'^details/(?P<book_id>\d+)$', 'books.views.details', 
        name="book_details"),
)

More Features

The rest of the application is described in the post titled:
How to Write Django Template Tags. You can also check out all of the code from the
google project by doing the following command:

svn co http://django-books.googlecode.com/svn/trunk books

in a directory on the python path.

Related posts:

  1. How to Write Django Template Tags Template tags can be useful for making your applications more…
  2. How to Add Locations to Python Path for Reusable Django Apps In my previous post I talk about reusable apps, but…
  3. How to Display Realtime Traffic Analytics Users of Presskit’n have been asking for traffic statistics on…

Django Settings Site Domain example.com

posted on January 5th, 2009 by Greg Allard in Greg's Posts on Code Spatter

It took me a while to figure out how to change from the default, example.com. Maybe it should have been obvious, but I was looking in all the wrong places and every search I did wouldn’t come up with an answer. As I discovered, it isn’t a setting in the settings.py file. It’s something that is in the database. You can change it through the Django admin interface, phpMyAdmin, or how ever you feel comfortable. It’s in the django_site table. When setting SITE_ID in settings.py it is the ID in this table. And this is the information that Site.objects.get_current().domain uses. Which is awesome for rss feeds and e-mails that you send out or anytime you need the domain in a link.

from django.contrib.sites.models import Site
domain = Site.objects.get_current().domain

Related posts:

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  2. How to Speed up Your Django Sites with NginX, Memcached, and django-compress A lot of t
  3. How to Add Locations to Python Path for Reusable Django Apps In my
    pre