Django: "projects" vs "apps"

Once you graduate from using startproject and startapp, there's nothing to stop you from combining a "project" and "app" in the same Python package. A project is really nothing more than a settings module, and an app is really nothing more than a models module—everything else is optional.

For small sites, it's entirely reasonable to have something like:

site/    models.py    settings.py    tests.py    urls.py    views.py

Try to answer question: "What does my application do?". If you cannot answer in a single sentence, then maybe you can split it into several apps with cleaner logic.

I read this thought somewhere soon after I've started to work with django and I find that I ask this question of myself quite often and it helps me.

Your apps don't have to be reusable, they can depend on each other, but they should do one thing.

What is to stop you using myproduct.myproduct? What you need to achieve that roughly consists of doing this:

django-admin.py startproject myproductcd myproductmkdir myproducttouch myproduct/__init__.pytouch myproduct/models.pytouch myproduct/views.py

and so on. Would it help if I said views.py doesn't have to be called views.py? Provided you can name, on the python path, a function (usually package.package.views.function_name) it will get handled. Simple as that. All this "project"/"app" stuff is just python packages.

Now, how are you supposed to do it? Or rather, how might I do it? Well, if you create a significant piece of reusable functionality, like say a markup editor, that's when you create a "top level app" which might contain widgets.py, fields.py, context_processors.py etc - all things you might want to import.

Similarly, if you can create something like a blog in a format that is pretty generic across installs, you can wrap it up in an app, with its own template, static content folder etc, and configure an instance of a django project to use that app's content.

There are no hard and fast rules saying you must do this, but it is one of the goals of the framework. The fact that everything, templates included, allows you to include from some common base means your blog should fit snugly into any other setup, simply by looking after its own part.

However, to address your actual concern, yes, nothing says you can't work with the top level project folder. That's what apps do and you can do it if you really want to. I tend not to, however, for several reasons:

• Django's default setup doesn't do it.
• Often, I want to create a main app, so I create one, usually called website. However, at a later date I might want to develop original functionality just for this site. With a view to making it removable (whether or not I ever do) I tend to then create a separate directory. This also means I can drop said functionality just by unlinking that package from the config and removing the folder, rather than a complex delete the right urls from a global urls.py folder.
• Very often, even when I want to make something independent, it needs somewhere to live whilst I look after it / make it independent. Basically the above case, but for stuff I do intend to make generic.
• My top level folder often contains a few other things, including but not limited to wsgi scripts, sql scripts etc.
• django's management extensions rely on subdirectories. So it makes sense to name packages appropriately.

In short, the reason there is a convention is the same as any other convention - it helps when it comes to others working with your project. If I see fields.py I immediately expect code in it to subclass django's field, whereas if I see inputtypes.py I might not be so clear on what that means without looking at it.