I'm new to Django and Mongodb seems really cool and I have a few
questions ! I'm using Django nonrel with Django Mongodb Engine.
I hope I'll not make too many mistakes :)
1 ) Are the Django user authentication system and the Django Session
system working fine ? Because I see on allbuttonspressed.com that
there is a problem with authentication and admin interface and the
part with the 3rd party written authentication backend makes me think
that the django authentication system doesn't work with mongodb :
You can only edit users in the admin interface if you add
"djangotoolbox" to your INSTALLED_APPS. Otherwise you'll get an
exception about an unsupported query which requires JOINs.
Florian Hahn has also written an authentication backend which provides
permission support on non-relational backends. You should use that
backend if you want to use Django's permission system.
2) If the authentication system works fine, how can I add fields to
the user model ? I saw on the Django docs that to achieve that the way
to go is to define a model with a OnetoOnefield to the user model
( "user = models.OneToOneField(User)" ) and define the other fields we
want in that model. I get it that must be the right way with SQL
databases. But with NoSQL like mongodb that just seem wrong to me, if
I'm not mistaken it creates a new collection and puts in each document
an user field used to link the document to the document in the User
collection ( exactly like a foreign key ). That doesn't seem to be a
NoSQL way at all ( Well It's just my feeling but since I'm just a
beginner I may be wrong, don't hesitate to correct me ). Is there a
recommended way to add fields directly to the User model ?
3) When the Model is used in Django, it puts all the fields in the
document even if they are empty right ? Isn't that a waste of space to
write down a lot of fields names in documents if they are empty ?
4) This question is more about Mongodb itself than the engine but I'll
ask it anyway, you may have the answer : How much extra space does it
take to index a field in a collection ?
Didn't think I would have written so much, I hope some of you had the
courage to read me !
Thanks in advance,
Nolhian
Only a partial answer as I don't use MongoDB.
I'm using django-nonrel in a Google AppEngine project. I'm using those other custom apps like "djangotoolbox", and some backends for GAE. Admin panel and standard Django authentication are working very well. I suspect it's the same for MongoDB (like mentioned in the quotation you have provided)
You're right. The standard approach is definitely good for relational databases, but might not work or work inefficiently for NoSQL databases. The typical scenario is to duplicate the data to another table, so you don't have to do JOINs. I think you can simply subclass the User model and add your fields to your custom model (docs).
Related
I have written one Django cloud based app. This app will have multiple user and for them multiple database, so that their data should be separate and they can save only to same database.
1) How can we implement it
2) How to automatically one user from login page to assign the database to write on it.
I don't have a complete answer, since you do not give a lot of detail. But here are a couple ots that f hinDjango supports custom database router implementations. A database router is a class that helps django decide which database to use for a particular model. Unfortunately I don't think this mechanism is granular enough for your needs. You can also specify the database to use in your code by using using(name) queryset method and save(using=name) form of save() method for instances. Of course this also means that some features of Django are going to be unvailable to you, since you cannot always expect to have a user. Look at the docs here for more info
https://docs.djangoproject.com/en/dev/topics/db/multi-db/
I'm learning Django on Ubuntu 13.04, Python 2.7, Django 1.5, Postgres 9.2,
Bootstrap 3.0. I'd like to achieve a combination of the tutorial example Polls app with django-authentication.
As my first effort I got the Polls app working from the Django 1.5 tutorial. I then installed django-registration 1.0 and these templates to make it work. I chose that package for authentication as opposed to django-allauth as a result of my question on authentication framework.
Now I want to integrate Polls and django-registration to record a set of results per user. After the poll results have been collected the admininstrator uses Django Admin interface to run a script to analyse the results (e.g. compute some statistics) and send an email to a subset of all users.
I briefly looked at two existing projects that looked like could get me there out of the box.
Light Bird's Questionnaire App was too complicated using a custom library of modular class based views. I'd like to keep it as simple as possible, using as much of out-of-the-box Django 1.5 functionality as possible for ease of maintenance and initial design.
Pinax web framework on top of Django, although a great idea, seems to be stuck in dark ages of 2011 with latest code supporting only Django 1.4 and Bootstrap 2.x. Starter projects don't look that useful and documentation isn't flash either.
Based on the above it looks like I'll have to do the integration of Polls and registration manually. At first pass I was thinking roughly the following:
The poll & choice could be simplified down to just a numeric answer to a question.
At database level we would need a separate table.
The primary key would be the userid.
Each column would store one answer per.
I'm guessing this would need a class PollsResults in model.py that would include defining the primary key as User, which should exist via django-registration.
Exactly how to do that and what follows gets a bit hazy to me at the moment.
I'm sure the above is a simple exercise for a Django developer. Could anyone give me some starting hints or even better an existing project that does something similar?
It looks like you're slightly underestimating the power of using a framework such as django. For example, you don't really need to worry too much about tables in the database or what will be their primary keys, because django's Object Relational Mapper (ORM) takes care of a lot of that for you.
If you want to connect two models (database tables) in django you can use a foreignkey like this:
class ThingOne(models.Model):
name = models.CharField(max_length=50)
class ThingTwo(models.Model):
thing_one = models.ForeignKey('ThingOne')
The quotes around 'ThingOne' in my ForeignKey are actually unnecessary because the ThingOne model has already been defined, but I like to use quotes anyway because it means your ForeignKeys will also work for models defined below (in your code) the model linking to them.
You therefore just need to add a relationship between your Polls and User models. If one user might have many poll results you should probably use a ManyToManyField instead of a ForeignKey but the principle is the same. That should be enough to get you started.
I'm writing a web app using the django framework and I was just wondering what are the pros/cons of using the built-in django.contrib.auth.models.User model over my own user model?
Please explain in terms of performance, scalability and security.
Many thanks
I always use the contrib.auth.models.User model, as many other apps also use it. Even if you want to have differences, it usually ends up being simpler to extend using a UserProfile than to try to build your own.
Unless you need to integrate with an auth backend that doesn't reasonably fit with contrib.auth, there aren't really any reasons to roll your own authentication app. auth provides its own access control models, but if they don't match your needs you don't need to use them. it provides a number of auth backends but if none of them are quite an exact match, then you can write your own backend and still use the rest of contrib.auth
Following this post (I was looking for a library allowing me to declare Django models on a ldap backend), I have decided to use ldapdb. After having played a while with this library, I figured out that it doesn't reach the level of control I need, and I am therefore looking for other solutions. What I am thinking of now is implementing a Django db backend based on python-ldap.
EDIT
I need this because I am currently implementing a user/group management system on a ldap directory (it requires to be able to manipulate not only users, but different classes of ldap objects as well). So basically, I would like to be able to use (nearly) full Django orm, but with a ldap backend.
Because I love Django (and would be rather motivated in learning the dirty low-level details of db.backends), and because there's already a lot of things implemented in this project, I would like to stick to Django (unless somebody has a very good reason why I shouldn't, and a very good alternative !).
Do some of you have a simpler solution to this problem ?
Do some of you know about an implementation of such a thing (ldap db backend) ?
Do some of you know some good reads to get started on "implementing a Django db backend"?
Are some of you interested in helping with this project ?
You make a lot of bold statements such as "lots of things broken because of the way it is implemented" and "the subclassing is very very far from being complete", would you care to elaborate on them? As the author of django-ldapdb I would welcome your suggestions as to what you would like changed/fixed, that's what the django-ldapdb mailing list is for!
FYI, I took the approach of subclassing the Model class because you will usually want to have just a couple of models using the LDAP backend, not all the models in your application, and django 1.1 did not support multiple databases. Also, LDAP is very different from existing SQL backends:
is not a relational database
it is not "flat", it is a tree-like
the true "primary key" for an entry is the Distinguished Name (DN), which is not an actual field, but a value computed from other fields
fields can be multi-valued
For all these reasons, I have serious doubts as to what can be achieved by writing a true LDAP backend. I think you will always have some LDAP-specific quirks, and subclassing Model allows just that.
Your best bet is probably to write an authentication backend for the application. Here is some documentation about it:
http://docs.djangoproject.com/en/dev/topics/auth/?from=olddocs#writing-an-authentication-backend
And here is an article that explains how to extend the User model to enable you to use this authentication backend seamlessly:
http://scottbarnham.com/blog/2008/08/21/extending-the-django-user-model-with-inheritance/
Seems like there's no really good solution. And doing everything without Django's ORM is no good solution either.
I'll make new attempt at solving that problem soon, with a django-orm-based solution.
I created a database for a site i'm doing using Django as the admin backend. However because the server where the site is hosted on, won't be able to support Python, I find myself needing to do the front end in PHP and as such i've decided to use CodeIgniter along with Datamapper to map the models/relationship.
However DataMapper requires the tables to be in a specific format for it to work, and Django maps its tables differently, using the App name as the prefix in the table. I've tried using the prefix & join_prefix vars in datamapper but still doesn't map them correctly.
Has anyone used a combination of this? and if so how have the fixed the issue of db table names being inconsistent? Is there anything out there that i can use to make them work together?
----edit: clarification on backend---
Let me clarify: i'm going to be running the admin from a subdomain pointing to a python ready server. However i can't move the main domain name from the php only webserver because of certain constraints/binding contracts the company got itself in. and don't want to use cloaking/masking because of seo purposes.
i'm using the django admin because i'm using some packages to make a pretty/functional admin, such as grappelli for the admin template, along with its editor for editing news stories, etc. also using photologue to manage photos/galleries. etc.
If your problem is simply making Django use the same tables as your other software, use the db_column and db_table parameters in the models.
http://www.djangoproject.com/documentation/models/custom_columns/
Two apparent solutions:
Instead of hacking one or both to work well with each other, emulate the Django admin in PHP/CodeIgniter code. **
Get a server that supports Django. Make the frontend in Django.
Time-wise, either one of those solutions will be less involving than trying to make two different frameworks using different programming languages mesh well together. I can't imagine the future maintenance required to ensure everlasting compatibility and interoperability.
Also, I assume by saying:
I created a database for a site i'm doing using Django as the admin backend
You really mean that you modeled your apps using Django, and that you also intend on administrating the database that has resulted from this modeling in the Django admin. (In which case you already have your Models layer complete and should just try building the rest of the site in Django)
If that's the case then in your models you are going to need to define the exact column names (db_column) that DataMapper will expect, as well as manually define the table names (db_table), including M2M tables.
You may also have to define all of your primary keys manually, if DM expects something named differently.
Also:
If the server can't support Python, where are you going to be running your backend? Different server? Locally? This plan just isn't making a lot of sense.
** I would not suggest trying this. I had been attempting to make a CI backend that actually shared much of the same ideas as Django's admin, before I knew about Django's admin. And of course once discovering Django, I dropped the CI work immediately and continued on with what I have found to be a much more amazing framework that is much faster to develop on.
So as I understand you plan on using Django just because of django-admin, and you are trying to use CI for the actual site because the server runs PHP, right?
So why don't you use framework that generates something like Django's admin but that you can run on your server?
The Symfony Framework has a really nice admin generator, in the spirit of Django's and you might be able to run it on your server. This would save you from the maintainance nightmare that might come later as #jonwd7 answered