django -- application subdirectory site/app1/app2/app3

Question

Hello,

If you were to write an app for a site, but wanted to make the app plug&play so you can just drop it in any Django project, set the main URL and there you go, how would you do that if you wanted to keep all the other required utility apps included in your portable app.

Example:

site/
site/site-app1
site/templates/site-app1
site/util-app1
site/util-app2
site/util-app3

Note: that the site-app1 makes the use of all three util-apps. It works great in this manner. But now, you decide to send the app to someone, but just that app with all its dependencies.

If we could package and send the apps like this?:

site/site-app1
site/site-app1/template
site/site-app1/util-app1
site/site-app1/util-app2
site/site-app1/util-app3

Then you just send site-app1 and everything goes with it.

Is there a way to make portable with utility apps as subdirctories?

Note: the idea is that we don't want to send the whole project, but one site-app within the project only.

Answer 1

There have been a few presentations about reusable django apps, so search around. These should get you going:

• Developing reusable apps. pdf and video
• Django Templates: The Power of Inheritance

Answer 2

The presentations @Gerry links to are good sources of general info. To answer your question more directly, there isn't a way to package one app inside of another one (EDIT sorry, this is just plain wrong. You can put one app inside of another one's namespace, and it works just fine. It's an odd thing to do though: you're implying that the one app is a part of the other one; if that's true they'd be easier to use as a single app. So I'd still recommend one of the below options). AFAICT your options are:

1. If possible, make those external dependencies optional (i.e. enhanced functionality if util_app1 is available, fallback behavior if it isn't). This is how many apps behave with respect to, say, django-tagging or django-mailer.

2. Roll all the functionality into a single app. Depending how much code you actually depend on from the utility apps, if the dependencies are absolutely necessary for your app to function, this might be the best option to make things easy on your users.

3. Package and distribute all the apps separately and note the dependencies both in the documentation and in the setup.py install_requires. If all the apps are independently useful, this approach may be best. If they aren't all independently useful, why are they all separate apps?

Answer 3

Django applications can be made portable by adhering to certain practices. Ofcourse, these are not mandated

Application Location

The convention is to add applications in an apps/ directory, and to modify the manage.py (and eventually the apache config) to include

import sys
from os.path import abspath, dirname, join
PROJECT_ROOT = abspath(dirname(__file__))
sys.path.insert(0, join(PROJECT_ROOT, "apps"))

Your directory structure will look something like

site
site/apps/
site/apps/app1/
site/apps/app2/

Templates

Templates are located in the templates directory in the application. The convention is not to force the user to copy them in any other location. Eventually the user can have global templates to override the ones in the application.

Settings

Keep all default settings in a local file within the app directory. The settings would be overridden by the global settings. The local settings file will have the following structure..

from django.conf import settings

def get(key, default):
    return getattr(settings, key, default)

SETTING_1 = get('SETTTING_1', 10)

These conventions should cover most major issues.