Develop Reference

Is there a way to automatically generate a whole system for different users [duplicate]

I have developed Multi-tenant SAAS apps in PHP/Laravel but recently I had a challenge to develop one in Django/Python. I am still learning Django though and I really like Django rest framework (DRF). But I have difficulties to figure out the highlighted areas below, If someone shows some light, I will be good to go:
How to handle subdomains/domains and selecting the right tenant db
How to manage and dynamically handle different database in django
Can multi-tenant apps backend still be managed from Django admin interface
I will be using queues and other apps scalling techniques, need tips and tricks if any
Any example out there
Any challenge experience when developing SAAS through Django

Well...
django-subdomains
There are people who asked in SO questions about dynamic databases in django (including, ahem... me). I'm not entirely sure I understood what you mean by "dynamically handle different database" so I guess just go to the links I just mentioned and pick out the best one for your project. (also - perhaps this is more relevant?)
Check out django-multitenant-schemas and this answer too.
There was a video of the guys behind Disqus (one of the largest django app in the world) explaining how they handle scaling. Here another interesting article on the subject. Also, the legendary SO question Does Django Scale.
(and 6.) Check out this answer
I hope that's detailed enough. I know this might be a disappointing only-links answer, but this is the reality of it - Django is a newer framework, and web development with python is still less common than php. With that in mind, understand that for all the awesomness of django (and it is awesome), with more complex needs there's more you'll have to do yourself.
In this case, you'll have to figure out how to do each part of the way seperatly and then combine it all. You can easily find a way to create a REST django app for example, but then you'll need to figure out how to combine it with another package (such as the above subdomains).
You can find a million examples out there of people doing freaky things with django. It's really powerful (when I learned about dynamic models I was blown away). But the more complex your app, the more you'll need to do yourself.
Pick it up, one step at a time, and come back to SO with specific issues you're having (or the django users google group). Good luck!

Can Rails & Django (now) query more than one database at a time?

EDIT: Since you are asking for specifics, consider a photo-sharing site (like Flickr or picasa - - I know that one uses PHP, while the other uses Python) for instance. If it proves to be successful, it needs to scale enormously. I hope this is specific enough.
It's been sometime since I heard any discussion on this, and since I am in the decision making process of choosing between Ruby and Python for a web project, here come the questions:
[1] Can current versions of Rails (Ruby) and Django (Python) query more than one database at a time?
[2] I also read on SO that "If your focus is building web-sites or web-applications go Ruby" (because it has fully featured, web-focused Rails). But that was about 2 years ago. What's the state of Python web framework Django today? Is it head-to-head with Rails now?
EDIT: [3] Don't know if I can ask this here, it's really surprising how quickly the Stack Exchange sites load. Do SE sites still use the same technology mentioned here? If not, does anyone have an update?

There's nothing in either of the languages that would prevent you from connecting to more than one database at a time. The real question is why would you want to?
The reason the StackOverflow sites are so fast is not so much the choice of technology but they way it's applied. Database optimization techniques are largely independent of the platform involved, just based on common-sense principles and proven methods of scaling.
Ruby on Rails offers a number of methods for connecting to multiple databases, though you might mean connecting to a system that's divided into shards, into multi-tenant partitions, or where different forms of data are stored on different databases. All of these approaches are supported, but they are quite different in implementation.
You should post a new question with an outline of the problem you're trying to solve if you want a specific answer.

Multi-database support exists in Django. In our Django project we have models pulling data from Postgres, MySQL, Oracle, and MS SQL Server (there are various issues depending on the database, but it all generally works). From what I've read, RoR supports multiple databases as well. Each framework comes with its own set of strengths and weaknesses which you have to evaluate against your particular needs and requirements. I don't think anyone can give you a (valid/useful) general answer without knowing the specifics of your situation.

Do I need to use a web framework for a simple website?

The site won't be that complicated and will resemble a modern blog (users, messages, news and other similar features).
Do I need to use a framework for this, and if so, which is best?
Pyramid, Django?

You certainly don't need a webframework to create a simple website. Given that you're new to python and interested in building a python website, I imagine this implies: you're interested in learning python. If you're exclusively interested in learning django-python, there's no reason you can't jump in to django, as Ronak said, of course. He's right. It has a lot of documentation. But it will make for somewhat of an odd intro to python.
If I were in your shoes, I'd either start making some offline programs first, or consider an ultra-lightweight framework. Many would advocate web2py or pyramid for ultralightweight. I might consider going even lighter. Something like Bottle, where you're more or less just pairing functions with urls. This way you can at least do a bit of hacking/trial-and-error, instead of launching right into django.
It's not that django doesn't use python-- it will tell you many times that it is in fact 'just python.' But it's adapted at its core to be used in a large business setting (the chicago something or other online, i think). So it enforces various rules that are helpful in managing many different employees working on a project together. You may or may not wish for this kind of 'help.' It also means the scale of projects is assumed to be large and the time-horizon, limitless. If you want to see how a python dictionary works, you may not want to spend a long time configuring settings and creating the pseudo-static-typing you need for your database, and so on, just to execute your project and see a result.
I realize I will automatically get downvoted for this, but I believe it to be sound advice.

It depends on what kind of website you are planning to come up with. If the website is going to be just a set of static HTML files, then you don't really need a framework. But if your website will have lots of dynamic content that will get updated on regular basis, you should go with some framework. That will make your life maintaining the website much more simpler.
Django is the most popular framework written in Python. It has very good documentation and a strong community base too.

Go with Django - 10,000 Elvis fans can't be wrong.
Or roll your own from scratch. You'll learn a lot, know everything about how you site works, and better appreciate what a framework does for you.

As RonakG first pointed, it all depends on the kind of website you intend to have up and running. Actually, your question is too general for a single, definitive answer. There are more aspects to consider other than just being in python. For example, deadlines. This means considering the learning curve to achieve your results. If you don't have much time, a steep learning curve (time to learn it in order to develop it) is certainly something you will want to avoid. Perhaps you already develop in other languages, and need integration and/or migration support, need scalability, reusability, etc, etc, etc.
Another thing that is not so clear in your question is what you mean by "The site won't be that complicated and will resemble a modern blog (users, messages, news and other similar features)". If it really resembles just a modern blog, with users, messages and news, you could google for CMS (Content Management Systems). There are many options available, that could make you have your site up and running in almost no-time. All you'll have to learn is how to customize whatever it has to as to comply to your needs.
That said, if you prefer python, there are some good CMSs available which you can develop your site fast, like Plone. And if you prefer Django, there's Django CMS and there's the excellent Pinax project, which takes the django code reusability to deliver you sample fully customizable, complete websites.

What's the best way to start learning django? [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
We don’t allow questions seeking recommendations for books, tools, software libraries, and more. You can edit the question so it can be answered with facts and citations.
Closed 7 years ago.
Locked. This question and its answers are locked because the question is off-topic but has historical significance. It is not currently accepting new answers or interactions.
I really want to build a web application; something simple, maybe a database of Pokémon cards for instance?
I've heard excellent things about Django. Where would be the best place to start?

This is from a post I made on my blog, answering almost exactly same question. It contains many of the answers already given here, as well as some extra advice, and some of it is my personal opinion, and others may differ from me. Hopefully someone finds it useful:
Build Something
The best advice I can give is to start by building something. A typical "Hello world" for Django is a blog website, and I would also recommend starting with that. The Django framework tries to make common tasks extremely easy and simple, and a website with simple blogging functionality is a typical example. A fluent Djangonaut can code up a simple blog website in less than an hour by using all the libraries available, and therefore it's a good place to start and get a feel for how Django does things.
The Django Book
Of course, before you can just jump in and start coding, you need to get your system up and running with Django, and learn the basics. A great resource for that is the Django Book. The authors haven't worked on it in a while or kept it quite up to date (due to its young nature, Django changes quite frequently), but It's freely available online and highly recommended. Read the first few chapters on how to set up your system, how all the parts of Django fit together into the MVC model, and be amazed by how Django does things so simply that other frameworks made unnecisarily tiresome.
The Django Tutorials and Documentation
There are so many great tutorials on the Django website, that you'll almost need nothing else once you have the basics of Django down. The documentation is also fantastic, go take a look for yourself.
Pick a Django Version
For a beginner, it will be a good idea to pick a Django version, and stick with it. At the time of this writing, there are two main versions being used by most, Django 1.2 and Django 1.3, as well as the development version (the version that the Django developers work on and test changes in before it gets released as a major version). Don't use the development version when you're starting out - you're bound to run into trouble.
The big thing is that Django has existed for around four or five years now, and much of the tutorials you'll find scattered over Google will be aimed at Django 1.0 and 1.1. That's fine, and mostly not a problem, but Django's added quite a lot of functionality since then that makes most of those tutorials and code snippets obsolete. Try to stick to tutorials that are aimed at your version, where possible.
Once you've picked a version, make sure you always read the correct version of the Django documentation. You'll see on the right-hand side sidebar and in the url of the page you are on that you can change the version you're looking at. Django's documentaion is truly excellent and far beyond anything else out there, and the authors take great care to specifically state which functions are new to that version, and which are deprecated in later versions. Just make sure you're aware of that, so that you don't waste countless hours trying to make something work that's not available in your version.
Know what DRY means, and practice it
DRY: "Don't Repeat Yourself" is one of the core principles behind Django. If you find yourself copy-pasting anything in Django, there's almost certainly a better way to do it. Most programmers will know from experience why repitition like that is bad, but in short, if something in your code needs to change later on or if you made a mistake somewhere, you only need to change it in one place. That's useful, because if there is more than one place needing change, and you forget about that instance, you'll be introducing errors and bugs into your code.
Stay away from Class-based views
A new addition to Django 1.3 is a whole array of Class-based Generic Views. If you don't know what that means, don't worry. The vast majority of tutorials and books about Django won't make any mention of it, mainly because it is so new. It's a feature that is meant to lessen the repitition in creating views, thereby following the DRY principle. While it does do that to some extent, it also introduces a lot of black magic and the need to frequently go scratch around in the Django source code to see what's going on. For the beginner, that is less than ideal. In addition, the error messages as they are now provided for Class-based views often point you in the completely wrong direction. Stay away from them, and rather use functional views in the beginning, as most tutorials will tell you to. When you're a bit more used to Django and you find the repitition of functional views frustrating, look into Class-based Generic Views.
Don't start out hosting on Google App Engine
While GAE is free and great for scalable Django apps, it also introduces a lot of restrictions on your login process, and the documentation on that is extremely scarce. As a beginner, don't start out with that route, since lots of the normal Django documentation will suddenly not apply, and you won't know what to do. Rather, start with a service like epio, gondor.io, or many others . Epio's still in beta, but have a free hosting option as well (up to a certain amount of monthly usage). Developed by two of the Django core developers, I strongly recommend using them - it's comparable to Heroku for Ruby on Rails. Ep.io is closing down, but Heroku also recently added a Python hosting option.
Use StackOverflow, Ask questions
My final piece of advice is to make use of StackOverflow any time you get stuck. First off, they already have the answer to just about any question you can dream of. If you can't find it on the site, a good way to find the answer to your question is to append "stackoverflow" as part of your google search terms. Otherwise, post a question and let the Django community help you out. It's proven to be my greatest resource in learning the darker sides of Django over the last few years, apart from physically reading the Django code (which you should also do!). Good luck, and enjoy!

Build your first Django web application by reading Django tutorial.

Read through the Django book.

Build something. Anything. Keep it relatively simple and short, but start building it and make sure you finish building it. The project you have in mind right there might be perfect.
Reading documentation and books is extremely helpful, of course, but like any programming the only way to really learn Django is to practice with it. Building something tangible is pretty much the only way to get that practice.

If you don't know Python, start your learning with that. People tend to get very frustrated when they try to learn a framework without knowing at least something about its programming language.

After obtaining basic knowledge of Django/Python, start reading Django by Examples, great articles.

The following screencast/tutorial is a nice way to jump in and create a Wiki from scratch:
Learn Django: Create a Wiki in 20 minutes
After that, you might work through the tutorials and documentation available at the excellent django documentation site.

You can try "Learn Django in 4 hours - a fast track tutorial"
For a kickstart into Django, please see:
http://slash4.de/blog/learn-django-in-4-hours
It is designed to get you started with Django as fast as possible (no installation routines, etc.). It shows all the most important parts of Django - of course it is not possible to cover all aspects of Django in 4 hours, but this is not the intention of this course.

Django, Turbo Gears, Web2Py, which is better for what?

I got a project in mind that makes it worth to finally take the plunge into programming.
After reading a lot of stuff, here and elsewhere, I'm set on making Python the one I learn for now, over C# or java. What convinced me the most was actually Paul Graham's excursions on programming languages and Lisp, though Arc is in the experimental stage, which wouldn't help me do this web app right now.
As for web app fast, I've checked out Django, Turbo Gears and Py2Web. In spite of spending a lot of time reading, I still have no clue which one I should use.
1) Django certainly has the nicest online presence, and a nicely done onsite tutorial, they sure know how to show off their thing.
2) Web2Py attracted me with its no-install-needed and the claim of making Django look complicated. But when you dig around on their website, you quickly find content that hasn't been updated in years with broken external links... There's ghosts on that website that make someone not intimately familiar with the project worry if it might be flatlining.
3) Turbo Gears ...I guess its modular too. People who wrote about it loved it... I couldn't find anything specific that might make it special over Django.
I haven't decided on an IDE yet, though I read all the answers to the Intellisense code completion post here. Showing extra code snippets would be cool too for noobs like me, but I suppose I should choose my web frame work first and then pick an editor that will work well with it.
Since probably no framework is hands down the best at everything, I will give some specifics on the app I want to build:
It will use MySQL, it needs register/sign-in, and there will be a load of simple math operations on data from input and SQL queries. I've completed a functional prototype in Excel, so I know exactly what I want to build, which I hope will help me overcome my noobness. I'll be a small app, nothing big.
And I don't want to see any HTML while building it ;-)
PS: thanks to the people running Stackoverflow, found this place just at the right moment too!

You should look at the web2py online documentation (http://web2py.com/book). It comes with a Role Based Access Control (the most general access control mechanism) and it is very granular, you can grant access for specific operation on specific records. It comes with a web based IDE but you can use WingIDE, Eclipse and PyCharm too. It comes with helper system that allows you to generate HTML without using HTML. Here is an example of a complete app that requires users to register/login/post messages:
db.define_table('message',Field('body'),Field('author',db.auth_user))
#auth.requires_login()
def index():
db.message.author.default=auth.user.id
db.message.author.writable=False
return dict(form=crud.create(db.message),
messages=db(db.message.id>0).select())
The web2py project is very active as you can see from the list of changes http://code.google.com/p/web2py/source/list
If you have web2py related questions I strongly suggest you join the web2py mailing list:
http://groups.google.com/group/web2py/topics
We are very active and your questions will be answered very quickly.

I have to say as not particularly skilled developer, the speed at which I have been able to create using web2py has blown my mind. In large part due to the amazing community and the core value Massimo has of making the framework accessible.
When I started I had written 0 lines of code in Python
Never heard of web2py
I've been at it seriously for about a month and have progressed (in my usual fashion) from asking questions that no one could answer (because they didn't make any sense) to coding for hours at a time without picking up a book or asking a question.
I'm really impressed.

I've had positive experiences with Django.
Built-In Authentication and easy to use extensions for registration
Very good documentation
You probable write your HTML templates mostly in base.html, then just use template inheritance (Note: You'll need to write at least a little bit of HTML)
In contrast to Turbogears, Django is more 'out-of-the-box'
I don't have any experience with web2py, but from my impression, it tries to do a little to much 'out-of-the-box'

If you decide to go with Django, make sure that you use its Generic Views. They will save you from writing lots of code, both Python and HTML.
Also, unless there is a very specific reason for you to use MySQL, I advise you to switch to PostgreSQL. Django is much more oriented towards PostgreSQL and it's a much better database anyway.
The online Django documentation is great, this is what put it apart from all the other frameworks. I also recommend the book Practical Django Projects by James Bennett

Django: Heard it has the best administrative
interface. But uses it's own ORM, i.e. doesn't use SQL-Alchemy.
Web2py: Didn't research this.
Turbogears2:
Uses SQL-Alchemy by default, uses Catwalk for admin
interface, but documentation isn't as
great.
I chose Turbogears2 because it uses popular components, so I didn't have to learn anything new...

I've used both web2py and RoR extensively, and while RoR has gotten a lot of popularity and support in the past few years, web2py is simpler, cleaner, less "magical", and yet also offers more (useful) out-of-the-box functionality. I'd say that web2py has more potential than RoR, but it is a relatively new framework and does yet not have the maturity of RoR. (Despite that, though, I'd choose web2py over RoR any day...)

If you "don't want to see any HTML while building it" then you can forget Django. It is not focused on "point-click-done," it is focused on pros going from concept to production in the shortest time possible. The hierarchical nature of the templating language can lead to some very clean overall site layouts. I use Django for all of my larger sites and I love it.
Although it's written in PHP, not Python, you might take a look at the major new version of WordPress that came out about 2 or 3 months ago. In 3.0 they have come a long way from being a "blogs only" environment and there are tons of ready-made templates for it. Of course if you want to tweak a template, well, there's that nasty old HTML again. I am considering using it for my smaller clients that can't deal with the admin of a dedicated server, etc., that tends to come with a Django site.
Update:
Ah, I missed the semi-joke -- I was up too early and that tends to make me tone deaf to humor. As far as using templates from existing sites, I have done this quite successfully with a couple of sites, both those that were static and those originally driven by well-written PHP scripts. I recommend a careful reading of the {% extends %} and {% include %} docs. Both take either a string literal or a variable. I have used the later method and it can be quite useful for a site that has strong hierarchy distinguished by style changes across branches.
It is also worth the time to understand the search order for templates -- it can be used to good effect, but it can be puzzling if you don't grok it. See the template-related items in the settings.py file for this and other useful goodies.