JS+Django: streaming multi-part ajax responses (MXHR)

Ajax is great eh? What did it stand for again…? Asynchronuous Javascript And XML?

Anyone actually sending back XML in their Ajax app these days?

I find, if I have the choice, I’m using JSON for sending the data back. Then, for those times where you don’t want to duplicate all of the templating logic from the server in your Javascript code just to ‘Ajax’ a form or something, I find I will often render a bit of HTML and send that back, even if it feels a bit dirty. It’s easy and there’s a certain DRYness that’s undeniable.

So it’s only a matter of time before you start thinking, as I did, “Sure, I could make half a dozen separate XHR requests, but what I really need to do here is send back a package of identifiable HTML and JSON chunks.”

Some kind of multi-part response basically. Hang on, I’ve heard of that before… something to do with email, or file uploads?

Django: export CSV admin action

Just a quickie…

If you’ve ever needed this:

Then here’s some handy code to do that.

You can customise and use this action (actually a sort of action factory function) with any of your models which need it.

Django: optiongroups for your ModelChoice Field

With a normal Django ChoiceField you can specify choices either as a simple tuple of tuples (value, label pairs) or with an extra level structure to organise the choices into named groups. The Django Select widget will then happily render the choices into html optiongroups.

With a ModelChoiceField you don’t specify the choices directly, you give a queryset of results from the db, which just has a flat structure.

I’ve made a ‘GroupedModelChoiceField’ that allows to output optiongroups based on a field from the model in your queryset. Code is here on djangosnippets… simple as that!

More django-mptt goodness: FilteredSelectMultiple m2m widget

If you are using django-mptt to manage content (eg heirarchical categories) then it needs a bit of help to make a nice admin interface. For many-to-many fields, Django provides the quite nice FilteredSelectMultiple widget (a two-pane selection list with search box) but it only renders ‘flat’ lists… if you have a big category tree it’s going to be confusing to know what belongs to what. Also, list items are sorted alphabetically by the js, which won’t be what you want.

In this post I’ll be extending FilteredSelectMultiple to show the tree structure in the list:

Making admin bulk delete action work with django-mptt

For the past month and a half I have been learning Django (and therefore Python…) at my new job.

I’m very impressed how quick it has been to learn, and particularly with how complete and well thought-through the Django framework is. Python is nice too, I’m not missing all the $ signs, semi-colons and curly braces at all 🙂

For the project I’ve been working on we used django-mptt to manage a ‘Modified Pre-Order Tree Traversal‘ scheme for a heirarchical Category model.

django-mptt works great but to properly manage an mptt model in the django admin you have to do a bit of hacking: