Empty Thoughts

This Week in Django is a weekly podcast about all things Django.

This week we talk about quite a few source commits (kicking-ass), some cool projects from the community, the Tip of the Week, and a question from the IRC.

Let us know if downloads are better for those of you in Europe.

Please see the Show Notes below for all the pertinent information and links

Downloads

AAC Enhanced Podcast (50.3 MB, 1:01:06, AAC)

MP3 Edition (42 MB, 1:01:06, MP3)

OGG Edition (32.9 MB, 1:01:06, Vorbis)

The Enhanced Podcast version contains screenshots and easy access links to all of the items we discuss throughout the podcast.

Feeds Available

iTunes Feeds are available. By subscribing using the iTunes feeds the podcasts will automatically be downloaded for you when we release them.

iTunes Feeds

This Week in Django – AAC Edition

This Week in Django – MP3 Edition

Regular RSS Feeds

This Week in Django – AAC Edition

This Week in Django – MP3 Edition

This Week in Django – OGG Edition

Give Us Feedback

Want to give us some feedback on the show? We’re always looking for ideas or suggestions that will help improve each episode. Please contact us at feedback __at__ thisweekindjango.com.

Show Notes

Big News

Malcolm Tredinnick is back!!!

Tracking Trunk (1:08)

• QuerySet Refactor Cleanup – Several tickets related to QuerySet Refactor merge and unrelated but just database stuff in general:
  • Corrected DateQuerySet to handle nullable fields (7739) – Previously if the date field was nullable no results were returned.
  • Corrected values and values_list across nullable joins (7740) – Previously, if we were querying across a nullable join and then a non-nullable one, the second join would not be a LEFT OUTER join, which would exclude certain valid results from the result set.
  • (7741), (7773), and (7760) through (7766) – Lots of miscellaneous QuerySet changes
  • Delete multi-table objects correctly. (7784) – When model inheritance is used, the parent objects should be deleted as part of the delete() call on the child.
  • Changed the way extra() bits are handled when QuerySets? are merged. (7791)

• django.contrib.auth no longer requires Sites framework (7748)

• Allow cache tag timeout value to be a variable (7754)

• Removed an unused OrderingField (7794)

• Normalize file paths for get_FIELD_filename (7795)

• exact lookups in MySQL are now case-sensitive (7798)

• Enforce the required attribute on BooleanField (7799)

• Allow empty content in flatpages. (7807)

• Removed default ordering on the User class (7806)

Community Catchup (19:28)

• Django newforms-admin upgrade – Luke Plant discusses his experiences with upgrading to the Django NewForms-Admin branch. Great post if you’re considering making the jump.

• Kss in Django – KSS is a javascript framework that aims to allow Ajax development without javascript. It uses stylesheets with CSS-compliant syntax to setup behaviours in the client and a set of well-defined commands that are marshalled back from the server to manipulate the DOM.

• Oh Django Song – Creative Mac OS X snippet.

• Python and Django Setup for Mac OS X Leopard – Exhaustive walkthrough by David A Krauth on setting up Django on Mac OS X.

• Edit Inline Support for Generic Relations – Patrick Altman delivers an article discussing how he implemented edit-inline support for generic relations.

• Django code_swarm – A kick ass-swarm visualizer by Brian Rosner for the Django source code from initial release to today.
  • code_swarm – An experiment in organic software visualization.
  • SQLAlchemy Code Swarm

• The basics of creating a tumblelog with Django – Interesting post by Ryan Berg. Similar projects are Jelly-Roll and SyncR and Django Lifestream.
  • jellyroll
  • django-syncr
  • django-lifestream

• An Interview with Adrian Holovaty – Creator of Django – Another excellent interview by Shabda Raaj.

Tip of the Week (43:49)

Ever need to reorder the fields on your Model Form?

• CookBookNewFormsFieldOrdering – Post by Simon Willison.
• Django Wiki CookBook

class TranslationForm(BookForm):
    translator = forms.CharField(max_length=40)

    def __init__(self, *args, **kwargs):
        super(TranslationForm, self).__init__(*args, **kwargs)
        self.fields.keyOrder = ['title', 'author', 'translator', 'publisher', 'copyright']

IRC Ad Nauseam (47:10)

Django IRC FAQ

Backwards Incompatible Changes Information

Charlie O’Keefe say, “I’ve gotten into designing restful URL schemes, basically organizing a web app around resources. Learning Django I was frustrated to find that nothing seems to be done this way. Is there any tool that can help with that?”

• django-rest-interface – Google Summer of Code project by Andreas Stuhlmüller.

Thank You! (50:58)

• MacVim
  • Using TextMate with Django – Great TextMate bundle by Paul Bissex.
  • E Text Editor – Cool TextMate clone for Windows. Utilizes TextMate bundles.
  • Using Vim with Django

• BosnoWsgi – Brian Rosner’s Tool for managing WSGI processes
  • Monit – Great Unix System management
  • CherryPy – a pythonic, object-oriented HTTP framework.
  • Hosting a Django Site with Pure Python – Great post by Eric Florenzano.
  • Serving Django via CherryPy

• Bill Gates Retires
  • Bill Gates Unhinged – amazing email from Bill Gates about his frustrations with using Microsoft software.
  • TWiT Podcast
  • Story by Todd Bishop

• Brian Rosner
  • Brian Rosner Blog
  • Brian on Twitter
  • TWiD Live

• Michael on Twitter

I think I’m hanging out in the wrong channels:

Thanks Alex Gaynor, that was very creative.

I love stuff like this. It’s always nice to see the human side of someone like Bill Gates. With the volume of antitrust suits against the company, I imagine we’ll be seeing this kind of material for a long time to come.

“Someone decided to trash the one part of Windows that was usable? The file system is no longer usable. The registry is not usable. This program listing was one sane place but now it is all crapped up.”

and continues…

“The lack of attention to usability represented by these experiences blows my mind. I thought we had reached a low with Windows Network places or the messages I get when I try to use 802.11. (don’t you just love that root certificate message?)”

Hard to believe this was from 2003. Five years ago and nothing has changed…

If you have a few spare moments, you have to check this out. I’m pretty convinced this guy works for me. Thank you Jezdez for the cool links.

Someone please stop Brian Rosner. He’s out of control. Although I must say, no surprises on this one.

You have to word your invitations carefully. Depending on which way this goes, I might just cozy up to a nice glass of wine.

In the closing remarks of This Week in Django 26 Brian Rosner pointed out a code swarm visualization created for Python as well as a couple of other open source projects. Well, in typical Brian fashion, he couldn’t leave well enough alone, so he created a wicked cool Django Code-Swarm Visualization. Definitely check this out. Thanks Brian.

This Week in Django is a weekly podcast about all things Django.

This week we talk about the Django Software Foundation, some source commits, some cool projects from the community, a Tip of the Week. and a couple IRC items. It’s a packed show.

Please see the Show Notes below for all the pertinent information and links

Downloads

AAC Enhanced Podcast (55.8 MB, 1:08:08, AAC)

MP3 Edition (46.8 MB, 1:08:08, MP3)

OGG Edition (38.5 MB, 1:08:08, Vorbis)

The Enhanced Podcast version contains screenshots and easy access links to all of the items we discuss throughout the podcast.

Feeds Available

iTunes Feeds are available. By subscribing using the iTunes feeds the podcasts will automatically be downloaded for you when we release them.

iTunes Feeds

This Week in Django – AAC Edition

This Week in Django – MP3 Edition

Regular RSS Feeds

This Week in Django – AAC Edition

This Week in Django – MP3 Edition

This Week in Django – OGG Edition

Give Us Feedback

Want to give us some feedback on the show? We’re always looking for ideas or suggestions that will help improve each episode. Please contact us at feedback __at__ thisweekindjango.com.

Show Notes

SPONSOR: This Week in Django is brought you by Justin Lilly, who according to all historic accounts, once scissor kicked Angela Landsbury. Thank you Justin.

Big News (2:18)

New foundation for Django – Lawrence-Journal World announces new Django foundation and code commits change license ownership.

• Jacob Kaplan-Moss Signing Papers – History in the making.

Tracking Trunk (5:02)

• login view no longer assumes that set_test_cookie has been called. (7692)
  • This is mildly backwards-incompatible, but in the “now it works the way it should have all along” sense.

• Added a—traceback option to syncdb to provide a stack trace when custom SQL loading fails. Also added documentation for the—traceback option (7704)

• Fixed bug with Model.delete() which did not always delete objects in the right order. (7722)

Branching and Merging (9:50)

• Handle multiple e-mail addresses when checking if it was mistakenly entered. Also prevent e-mail guessing by checking password before throwing an error. (7694)

Community Catchup (15:57)

• DebugFooter Redux – Last week we talked about Andreas Marr very cool Django Snippet to add debug information into the footer of each webpage. This week he did it one better based on some suggestions from our program. Now that’s what I call Podcast Driven Development™.
  • django-loggin

• Django Tutorial – Abstract Base Classes vs Model Table Inheritance – Awesome post by Kevin Fricovsky that covers the difference between Abstract Base Classes and Multi-Table Inheritance.

• django_templatecomponents – A django application by Filip Noetzel that makes it easy organize your component source (javascript, css) right in your django templates to to make your website much faster.
  • Git Repository

• group_required Decorator – Matt Dennebaum offers a nice addition to your Django projects that adds the ability to check for authorization of a user against the specified group.

• django-ajax-validation – A reusable application by Alex Gaynor for doing ajax validation with django newforms. It requires jQuery.
  • Git repository also available
  • Ticket 2070 – Streaming file uploading by Mike Axiak.

• Fun with queryset-refactor – Another great post by James Bennett discussing some of the new features that were part of the Queryset-Refactor merge.
  • Practical Django Projects – Forthcoming book by James Bennett.

• Werkzeug Debugger in Django – The Werkzeug debugger has a kick ass AJAX based console option to debug traceback items in the web browser.
  • Changeset 7537
  • Ticket 3527 – Adds Werkzeug to Django directly.

• Let’s talk about documentation – Excellent post by James Bennett on how he approaches documentation for his Django projects.

Tip of the Week (43:22)

This tip comes from Alexander Solovyov in his blog post Render To Improved.

Sometimes you want to return a RequestContext from a view. One way to do that is to specify the response code using a decorator.

@render_to('mytemplate.html')
def myview(request):
  return ({'id': 1, 'name':'empty'})

# example with override
@render_to('mytemplate.html')
def myview(request):
  return ({'name':'empty'}, 'override.html')

# python 2.3 example with override
def myview(request):
  return ({'name':'empty'}, 'override.html')
myview = render_to(myview, 'mytemplate.html')

You can also return a tuple where the second item is a string that overrides the default template specified in render_to.

• Permalink Decorator – “A backwards remapper hulu-hooping dancer, thingy.”—brosner

IRC Ad Nauseam (51:11)

Django IRC FAQ

Backwards Incompatible Changes Information

What’s the difference between Abstract Base Classes and Multi-Table Inheritance?

Abstract Base Classes are where you provide a base class, like Person, and then a derived class like Employee. Django will create a single database table for the Person model that contains the combined fields from both the base and derived classes.

Multi-Table Inheritance also has the base and derived class but at the database level you end up with two tables: one for the base class and one for the derived class, with a one-to-one field added in to connect the two.

Again, we highly recommend the excellent post by Kevin Fricovsky that we mentioned in Community Catchup. Plus, as always, the excellent Django documentation.

• Abstract Base Classes – Django documentation on the subject.

• Multi-Table Inheritance – Django documentation on the subject.

Is there a way to pass the filter arguments as string to the QuerySet?

QuerySet parameters are standard Python keyword arguments, and can use standard keyword argument expansion.

Post.objects.filter(datetime__year=2008)

Post.objects.filter(**{'datetime__year': 2008})

• Dynamic Functions – Excellent post by Marty Alchin that discusses keyword arguments in a very easy to understand way.

Thank You!

• Facestat scales fast for Yahoo traffic
  • Scaling Fast by Lukas Biewald

• Eric Florenzano in Japan – Follow him in his travels. Lots of very cool pictures.

• Brian Rosner
  • Brian Rosner Blog
  • Brian on Twitter
  • TWiD Live

• Michael on Twitter

Someone is very creative. I love it!

“What the hell is going on? This is fucking incredible.” Jacob Kaplan-Moss said. Kaplan-Moss is the chief architect of Django and said nothing like this had ever happened before. “They’re all naked, and these chicks don’t shave anything!”

A new feature to come to the Django-Command-Extensions project is the implementation of a new management command called runserver_plus. For now the “plus” part means that I’ve replaced the standard Django traceback pages with the Werkzeug Debugger traceback page in it’s place.

Getting Started

This item requires that you have the Werkzeug WSGI utilities installed, in addition to the django-command-extensions app.

To get started we just use the `runserver_plus` command instead of the normal `runserver` command:

$ python manage.py runserver_plus

 * Running on http://127.0.0.1:8000/
 * Restarting with reloader...
Validating models...
0 errors found

Django version 0.97-newforms-admin-SVN-unknown, using settings 'screencasts.settings'
Development server is running at http://127.0.0.1:8000/
Using the Werkzeug debugger (http://werkzeug.pocoo.org/)
Quit the server with CONTROL-C.

Note: all normal runserver options apply. In other words, if you need to change the port number or the host information, you can do so like you would normally.

Using

Whenever we hit an exception in our code, instead of the normal Django traceback page appearing, we see the Werkzeug traceback page instead.

Along with the typical traceback information we have a couple of options. These options appear when you hover over a particular traceback line. Notice that two buttons appear to the right:

The options are:

View Source

This displays the source below the traceback:

Being able to view the source file is handy because you are able to get more context information around where the error occurred. The actual traceback areas are highlighted so they are easy to spot.

One awkward piece about this is that the page is not scrolled to the bottom. At first I thought nothing was happening because of this.

Interactive Debugging Console

When you click on this button a new pane will open up below the traceback line you’re on. This is the money shot:

An ajax based console appears in the pane and you can begin debugging away. Notice in the screenshot above I did a print environ to see what was in the environment parameter coming into the function.

Summary

I’ve only been using the Werkzeug debugger on my Django projects for a day now. But I’m loving it. I encourage you to check it out. Plus if you’re not a current Django-Command-Extensions user, you’re going to find tons of really cool additions in there.

WARNING: This should never be used in any kind of production environment. Not even for a quick check into a problem. I cannot emphasize this enough. The interactive debugger allows you to evaluate python code right against the server. You’ve been warned.