With Django, you can setup unit test data with fixtures. YAML fixtures are nicer than JSON or XML. But, honestly, setting up an object graph by looking at a flattened out text file is not fun. And using the application to setup test data, then exporting to fixtures is distracting. Examples coming soon.

So many displays available these days are short and wide. yet pep 8 instructs us to write code that is tall and thin (<80's chars wide)

Next monitor I get will be one that pivots or just be more squarish. This wide format is a mismatch for development. I have to scroll too much, and half of my screen is displaying nothing.

I know what you'll say, just resize your window to show 80 chars wide, and then stick something else like documentation or log windows in the extra space. My answer to that is, yes, I do that now. But, sometimes I just want to see as much code as I can. And I put the docs and logs in a second display.

Wing4.0 is a Django release. Here are the details. You should be able to find out what you need there. So I think I'll just put up some pictures.

Normal view method with a quick test class T to put in the context

Awesome!!! Breakpoints in a template.

While parked on that breakpoint, use the Debug Probe (pictured) and Call Stack (not pictured)

Note the test_func actually was called

Overview

The graph_models command of Django-Extensions will draw you a nice DB schema for your defined models.py. It's simple to use this to rapidly model your DB.

Steps

1. In a Django application, make some changes to models.py
2. Run this in an application directory (change 'yourapp') in your Django project to generate and display a graph
   python manage.py graph_models -o yourapp_models.png yourapp
3. Now you can view the graph with a png viewer - firefox will work
   firefox myapp_models.png
4. make changes to models.py, and repeat

You can group lines 2 and 3 like this. But, beware that if there is an error in the models, you might be looking at the old png There is one nice side affect. The models are validated when you create the graph. So, when the graph looks right , you can be assured that the models will be clean and ready for a migration. (You migrate, right? If not, try South) Comments welcome!!

Overview

When customizing the Django Admin, for example a change_list.html template, you might want to add some JavaScript of your own. If you just chuck in your jQuery code, using the $ alias, to the {% block extrahead %} you'll probably see $ is not a function in your browser's Error Console.

If you just intend to use the jQuery that the admin is loading, you'll find it is loaded in the {{block.super}} line below. But, Django also clears the $ alias to jQuery when loading and sets up the only jQuery alias to django.jQuery.

Reclaiming the $ alias

Consider this block of code

This will result in $ is not a function on a page reload. Add the line
var $ = django.jQuery to bring it back.

Final thoughts

This works for me, but I can imagine there might be a case when you don't want to redfine $ like this. Afterall, Django is clearing it for a reason. This is alternative solution.

Description

When you are coding these days, you might be using Mercurial or git for source control. Since these are distributed systems, there is no central repo. So you can't cheat and use it as your release procedure, like you could with cvs, and svn. I prefer to use Mercurial. When I'm ready to push code to a server, I put something like this my .bashrc file.

Brief Explanation

1. This sends the Django project test (and all files subdirectories) in the virtualenv directory 'test' to the server as an update (only altered files)
2. Any file that has been deleted locally, is deleted on the server.
3. Exclude the setting.py, so you don't stomp on the production one which is probably different.
4. Exclude .pyc files and anything that starts with .

Notes

• Fabric is a cool product, and I might start using that too to restart servers.
• Of course, if you are collaborating with a team, you probably have a git or hg hub. If so, you can still use this copy files from a testing area to a release area. So, you don't need a working directory on production.
• Of you have more than one server, you could certainly add more lines to that function.

If you want to use the python method locale.currency() to format numbers, you need to make sure you aren't set to the 'C' locale.

You can use the following and serve the code up with Django runserver with no problem. The Python documentation says that this call '...sets the locale...user’s default setting (typically specified in the LANG environment variable).'

If you use Apache, and WSGI to serve up your Django App, you need to include the locale value explicitly. Otherwise you may find the error: Currency formatting is not possible using the 'C' locale.

Incidentally, for my code to be internationalized, I will need to set the locale based on a User preference anyway, so relying on the server environment's setting would not be correct even if it worked.

Stop, There are some flaws in this. I'll fix it up soon and repost. If you understand South and Django, you can probably find the flaws. Beware.

Overview

A programmer using South is able to make rapid changes to the DB schema of a project over a short period of time. When it's time to check-in work, as a programmer, you may want to collapse the migrations you have created into one

Checking in all your migrations isn't a problem, but if you find you prefer to have a clean migration history you can have your programmers follow this procedure.

The steps

1. Reset your migration history for the app up to the last checked in migration.
   ./manage.py migrate appname --fake MIGRATION_NUMBER
   --fake means don't touch the application's DB. Just remove all migration rows from south_migrationhistory up to that migration number.
2. Remove all migration files up to that number
   rm appname/migrations/ALL_MIGRATIONS_OLDER_THAN MIGRATION_NUMBER
3. Recreate the "next" migration to match your current DB state.
   ./manage.py schemamigration appname --auto
4. Apply the migration to create the DB objects
   ./manage.py migrate appname

Alternatively, you might want to completely rebuild your DB. In this case, do the following

• In Step 1. Make MIGRATION_NUMBER the string 'zero'
  ./manage.py migrate appname zero
  This removes all migration history, and the DB. If this fails. You can use --fake, and then remove the DB manually.
• In Step 2, remove all the migrations
  rm appname/migrations/*
• In Step 3, do the following instead
  ./manage.py schemamigration appname --initial
  This creates the 0001 migration based on your models.
• Apply the migration to create the initial DB objects
  ./manage.py migrate appname

I just returned from a weeks holiday in Cairns with the family.

In the middle of the Cairns Night Market, along the Promenade, you will find Peter Nicholson with his pet Pythons. For a donation you can handle the snakes, and ask all sorts of questions.

If you are in Cairns, I highly recommend a visit. You can take as many photo's as you like.

One of the powerful features of WingIDE is that you can debug python code, even web applications and Django, with an interactive debugger that is fast and very feature full.

In this article I discuss how I use it with Django. Suppose you have a unit test that hits a relational DB. With Django you can run python manage.py test, to run these tests. When you test this way, Django will do the following

1. Create a test database, syncdb your tables, and load any data fixtures
2. Run the tests
3. Drop the test database

WingIDE has a Unit Testing interface, but it only allows you to run the tests. In other words, it only runs Step 2 above. I have found no easy way to have Wing do Step 1, then run your selected tests within Wing's Testing system, then do Step 3. I'm working on a way to do this, and will blog about it someday. For now, I run the Django Test system through Wing Debug system, and not through the testing system. Like this.

1. In your Django project, in Wing, Choose to edit the file properties for manage.py.
2. In the 'Debug' tab of this dialog, and the 'Run Arguments' box type test (and optionally the app name to run tests just for that app).
3. Now choose to Debug manage.py by right clicking on that file and choosing Debug Selected

This will cause WingIDE to run the Django test framework. Output will go into the Debug I/O panel. Wing will even stop at breakpoints and enter the debugger.

The advantages of this method

The tests can be run either on the commandline or within WingIDE without any changes or hacks to the source and it is simple to set up.

The disadvantages of this method

You don't get to use the rich Wing interface for running tests which would allow you to run individual tests on demand. Beware too that you might be using manage.py to run the Django runserver within WingIDE. That is also configured in the manage.py Debug dialog. You can only configure one argument to manage.py at a time.

Overview

Do you have a Django application that uses the Admin Site and you would like to add custom fields to the User object? Below I discuss a object oriented way of implementing this.

Explanation

Subclass User in models.py.

This allows us a place to add custom fields. For example, I've added a bio TextField and a relationship to a Club model object (not shown) to record the clubs to which the user belongs. For More information consider this explanation from scottbarnham.com

Subclass UserAdmin in your admin.py file.

This subclass allows us a way to add our fields to the standard fieldsets in UserAdmin. After coding this, and updating your database, load up your Django Admin, and have a look. Because MyUser does everything that User does, and more, we can register MyUser and unregister User.

If you want to build PDF's with a python program, then ReportLab software is what you need. Go get it. Set aside some time to read the manual: Reportlab Userguide.

If you have read up on ReportLabs and specifically Playpus, you'll probably think it's hugely powerful, but slightly confusing. The manual does a pretty good job, but I think it leaves out one important point.

When you are laying out your frames, they go across the page, and wrap if necessary. It is not natural to control their exactly placement, and it is not clear how to force a break in the layout. Here's an example

When building these elements, they will be next to each other, assuming the styles are not too wide. If you want them to be on their own lines, you need a line break. It is done like this That is it. It took me a bit of searching and I don't want to forget it, so I'm adding it here.

References

• http://stochasticgeometry.wordpress.com/2009/01/06/reportlab/
• http://two.pairlist.net/pipermail/reportlab-users/2004-November/003564.html

My name is Gene. I'm an entrepreneur and a programmer. This means I like to work with startup companies with new and interesting ideas. I also like coming up with my own ideas.

A blog is not my idea, but I did build this one myself. As I get time I will add features. It is a Python Django application with some jQuery tricks.

The purpose of this blog is to give me a place to log things I don't want to forget, and to share these things with others. My father used to talk about something called his "File of Miscellaneous Trivia." In a sense, this blog is my version of my dad's file.

I also hope to use this to show off the power of the various tools I use. Over time I hope to have a blog that is unique both in content and in features. Stay tuned. In fact, I hope to have rss going very soon.

Please leave comments.