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creating a new instance of todolist in every URL [duplicate]

I've googled around for this, but I still have trouble relating to what Django defines as "apps".
Should I create a new app for each piece of functionality in a site, even though it uses models from the main project?
Do you guys have good rule of thumb of when to split off a new app, and when to keep functionality together with the "main project" or other apps?

James Bennett has a wonderful set of slides on how to organize reusable apps in Django.

I prefer to think of Django applications as reusable modules or components than as "applications".
This helps me encapsulate and decouple certain features from one another, improving re-usability should I decide to share a particular "app" with the community at large, and maintainability.
My general approach is to bucket up specific features or feature sets into "apps" as though I were going to release them publicly. The hard part here is figuring out how big each bucket is.
A good trick I use is to imagine how my apps would be used if they were released publicly. This often encourages me to shrink the buckets and more clearly define its "purpose".

Here is the updated presentation on 6 September 2008.
DjangoCon 2008: Reusable Apps #7:53
Slide: Reusable_apps.pdf
Taken from the slide
Should this be its own application?
Is it completely unrelated to the app’s focus?
Is it orthogonal to whatever else I’m doing?
Will I need similar functionality on other sites?
If any of them is "Yes"? Then best to break it into a
separate application.

I tend to create new applications for each logically separate set of models. e.g.:
User Profiles
Forum Posts
Blog posts

The two best answers to this question I've found around the web are:
The Reusable Apps Talk (slides)(video) also mentioned in other answers. Bennett, the author and Django contributor, regularly publishes apps for others to use and has a strong viewpoint towards many small apps.
Doordash's Tips for Django at Scale which gives the opposite advice and says in their case they migrated to one single app after starting with many separate apps. They ran into problems with the migration dependency graph between apps.
Both sources agree that you should create a separate app in the following situations:
If you plan to reuse your app in another Django project (especially if you plan to publish it for others to reuse).
If the app has few or no dependencies between it and another app. Here you might be able to imagine an app running as its own microservice in the future.

The rule I follow is it should be a new app if I want to reuse the functionality in a different project.
If it needs deep understanding of the models in your project, it's probably more cohesive to stick it with the models.

The best answer to this question is given by Andrew Godwin (Django core developer):
The main purpose of apps is, in my eyes, to provide logical separation of reusable components - specifically, a first-class namespace for models/admin/etc. - and to provide an easy way to turn things “on” or “off”.
In some ways, it’s a relic of the time when Django was created - when Python packaging and modules were much less developed and you basically had to have your own solution to the problem. That said, it’s still a core part of Django’s mental model, and I think INSTALLED_APPS is still a cleaner, easier solution than Python’s replacement offering of entrypoints (which makes it quite hard to disable a package that is installed in an environment but which you don’t want to use).
Is there anything specifically you think could be decoupled from the app concept today? Models and admin need it for autodiscovery and a unique namespace prefix, so that’s hard to undo, and I’m struggling to think of other features you need it for (in fact, if all you want is just a library, you can make it a normal Python one - no need for the app wrapping unless you’re shipping models, templates or admin code IIRC)

An 'app' could be many different things, it all really comes down to taste. For example, let's say you are building a blog. Your app could be the entire blog, or you could have an 'admin' app, a 'site' app for all of the public views, an 'rss' app, a 'services' app so developers can interface with the blog in their own ways, etc.
I personally would make the blog itself the app, and break out the functionality within it. The blog could then be reused rather easily in other websites.
The nice thing about Django is that it will recognize any models.py file within any level of your directory tree as a file containing Django models. So breaking your functionality out into smaller 'sub apps' within an 'app' itself won't make anything more difficult.

developing a django cms

first of all i'd like to apologize if my problem seems to broad to answer but i'm really getting frustrated over this. so i'm a wordpress developer mainly (used to be a front end developer) and i'm getting into python django. but after taking many courses i can't seem to understand how to do the content management aspect of my project. so here is a rundown of my problem
in wordpress there is this concept of custom post meta where you can put fields that can change the heading of pages and fully customize the website so that the client won't need me every time he needs to change anything (CMS basically)
now i can't even begin to imagine how to go about doing something like that for django
i've tried putting a custom form on top of my list view in the admin page but that doesn't look so good and what if i need to customize a page that doesn't belong to a module with a list view
i've tried to make an app and call it page but then what about the stuff that is directly related to a module.
so my question is: how should i think about this since i don't want to go a long way in one direction just to discover that that is a poor way of doing things
also as a side note the site i'm creating is not that much bigger than a blog which i know i'd be better off doing in wordpress anyway but i thought it would be a good starting point to familiarize my self with django.
finally if you'd recommend any courses or maybe a tutorial i'd be more than grateful.

You're right, that is a very broad question. Here is a broad answer that I hope will help.
Django is a programming "framework" that can be used to develop new web-apps, including new CMS's. In my experience, the customizability of web-page titles in a new Django-app would involve using Django's html template language with template-tags and context-variables etc, as well as Python programming within the Django framework. For doing content management, you would basically have to program your own models & functions for that, along with whatever default or other database system (MySQL, PostgreSQL) you choose to install... There is a learning curve, but Python and Django are considered by some to be among the easiest language+frameworks to learn.
This tutorial playlist may help you. It helped me muddle thru Django in the beginning, and he has Python tutorials also.

Want to learn django with REST without rest frameworks

I am a php programmer, I have built some REST based solutions in php. Now I am learning python/django. I want to make a REST based solution in Django ( only for knowledge purpose ). I do not want to use any of REST frameworks/toolkits as This project is more a exploring django/python say how they work with raw REST concept.
I searched on net, But examples/tutorial filled on already built solutions. I also checkout for request method based filtering. I am thinking of two approaches.
Either urls.py have way to check request method and transfer to respective method in views.py.
Or I can add a pre load hook/class which determine request method on application initialize, And called respective method so overriding urls.py behavior (my preferred method).
If anybody can suggest a django way to do this?
Update : I found some interesting comments on SO, like https://stackoverflow.com/a/20898410/1230744 AND https://stackoverflow.com/a/1732520/1230744. Need to check if they can have the solution, I am searching.

Well I get the answer of my questions finally from following link. It is possible through using Class based Views + serialization.
Restful routes and Django
Snippet links in side above link gave pretty much example to gave quite picture of how one can create a REST Api using only Django Core. Also I used serialize https://docs.djangoproject.com/en/dev/topics/serialization/ for Json encoding
( Now if anybody prefer, he can flag duplicate the question. ;) )

You can start from learning the code of this projects:
http://tastypieapi.org/ Tastypie
http://www.django-rest-framework.org/ Django REST framework
They are snadrd de facto for REST API for Django and their code could be a good starting point.
Also, please review this questions:
Creating a REST API for a Django application
Adding REST to Django
Django and Restful APIs

Django Forum App Project Structure

EDIT: I'm new to this site but if you are going to down vote me, could you perhaps explain why? I've searched Google, this site and others but have not found anything that makes any sense and I thought this was a site to ask questions and get some help.
I've got a Custom PHP Forum that I am trying to convert to Python/Django as a learning experience and I'm having some problems. I've been reading up on Django and it is encouraged that our application is split into multiple apps. I went through the 6 part tutorial and many other parts of the documentation but I'm left with some questions.
Let's assume that I have about 30 tables.
Tables such as:
posts_index, posts, users, user_groups, user_activity, user_sessions, forums, payment_gateways, payment_logs, etc for a basic forum
I'm having issues structuring my models. With PHP all I needed was index.php, /admin/index.php, view_forum.php, view_thread.php and a few others, everything could pull directly from the database and I had no issues but now I have to deal with apps/modules.
I'm thinking I'd need to structure my apps in a manner similar to this:
/admin/ app
/forums/ app
/view_forum/ app
/view_thread/ app
/forums/view_forum/ app (instead of just /view_forum/, could be a sub app)
/forums/view_thread/ app (instead of /view_thread/, could be a sub app)
My problem and only question here is dealing with global state. For example Users/Group/Session/Logging/Permission information is going to need to be shared across multiple apps through importing in the other apps models file. To do this I need to reference their model information, what is the correct way to handle this?
Would either of these be acceptable?
Create a ton of different apps such as /users/ which would model my users_groups, users, user_sessions, another app for /posts/ that would include models for posts_index, forums, and so forth with these models existing but not actually being used publicly, they would be used in other apps only. They would be imported in areas such as the /view_forum/ app since when viewing a forum I might need to determine if the user is logged in, is a member of a particular group, etc and because of that would need access to a number of the hidden apps and hence would be imported from the hidden app.
What if I just had one single app, instead of it being an app it would just be my entire project. This sounds like the best solution to me but it seems to be suggested if we cannot summarize the entire application into a sentence it needs to be broken up. If I went with one single app being used as my entire project, my models file will have 30+ different models, is this acceptable? I assume not but figured I'd ask.
Do either of the above make any sense? If not what would you do fix it? I'll admit I'm lost so any feedback would mean a lot.
I'm new to Python/Django and am trying to figure things out. I hope I am clear on what I am trying to do. I'm more than welcome to any advice. I've been trying to play around with things but I figure it would be better to ask for advice from more experienced developers. I'm not a professional programmer and am still learning so please be nice :).

I have voted this up... I had similar questions when I first moved to Django (also coming from PHP)
Try not to think of apps in terms of db tables (or url paths), you want to create apps for independent pieces of functionality.
I would say most of your code will be in a single forum app with Forum and Post models in it and all your forum-related urls like /view_forum/ and /view_thread/. Note there's not really such thing as a sub-app in Django... these are different views which all belong to one related set of functionality in a single app.
The 'users' stuff... you normally want to hook in to the Django auth system (https://docs.djangoproject.com/en/dev/topics/auth/default/#user-objects) though if you are trying to keep the legacy database structure this may be harder... you may end up needing your own users app.
The payment gateways stuff sounds like another app again.
For the admin, you get this (almost) for free with Django:
https://docs.djangoproject.com/en/1.5/ref/contrib/admin/
You need an admin.py inside each app, where you register the models that you want to expose to the admin site.
You might find it's best to follow a tutorial and build a simple blog (or try and build a very simple minimal forum from scratch) to get a feel for Django before tackling your re-write. Because trying to exactly recreate the old functionality with legacy db tables will be a bit harder and may lead you into patterns which are not 'good Django'.
You might also find it useful to look at the source code of an existing Django forum app, such as this one:
https://bitbucket.org/slav0nic/djangobb/src/
They have just a single djangobb_forum app that does everything. I think this is entirely justified as a forum is a single complicated piece of functionality.
Note how their Profile model effectively extends the built-in Django auth.User model via a OneToOneField. It makes it easier to integrate with the built-in login and authentication system that way.

Start by integrating your legacy database and then build the Admin site. You'll see how the model information is available to the Admin app and every other app you write. The key is to import models in your apps.

How to customize admin filter in Django 1.4

I am a newbie in Python and Django Development, I learned a lot from the easy read examples provided by the community. But recently I want to implement a customized admin filter for the admin console shipped with Django. I searched a lot and only found some out-of-date approaches to get it done. Such as:
Custom Filter in Django Admin on Django 1.3 or below
I tried to read the source code for the filters module in 'django.contrib.admin' app, but unfortunately I can hardly understand the rationale behind the codes. So I wonder whether some kind people could supply some examples or references to this issue --- How to customize admin filter in Django 1.4 ?
Thanks in advance！

There is new django.contrib.admin.SimpleListFilter introduced in v1.4 meet your need, and official document provide sample code and easy to read.
search SimpleListFilter in this section.