What's the next steps for moving from appengine to full django?_问答_开发者

I'm super new to programming and I've been using appengine to help me learn python and general coding. I'm getting better quickly and I'm loving it all the way :)

Appengine was awesome for allowing me to just dive into writing my app and getting something live that works (see http://www.7bks.com/). But I'm realising that the longer I continue to learn on appengine the more I'm constraining myself and locking myself into a single system.

I'd like to move to developing on full django (since django looks super cool!). What are my next steps? To give you a feel for my level of knowledge:

I'm not a unix user
I'm not familiar with command line controls (I still use appengine/python completely via the appengine SDK)
I've never programmed in anything other than python, anywhere other than appengine
I know the word SQL, but don't know what MySQL is really or how to use it.

So, specifically:

What are the skills I need to learn to get up and running with full django/python?
If I'm going to host somewhere else I suppose I'll need to learn some sysadmin type skills (maybe even unix?). Is there anywhere that offers easy hosting (like appengine) but that supports django?
I hear such great things about heroku I'm considering switching to RoR and going there

I appreciate that I'm likely not quite ready to move away from appengine just yet but I'm a fiercely passionate learner (http://www.7bks.com/blog/179001) and would love it if I knew all the steps I 开发者_如何学Pythonneeded to learn so I could set about learning them. At the moment, I don't even know what the steps are I need to learn!

Thank you very much. Sorry this isn't a specific programming question but I've looked around and haven't found a good how-to for someone of my level of experience and I think others would appreciate a good roadmap for the things we need to learn to get up and running.

Thanks,

Tom

PS - if anyone is in London and fancies showing me the ropes in person that would be super awesome :)

First up, you can benefit by doing some RoR work by learning a new language. However, I don't know if that'll be entirely beneficial to you right now since you still are learning. I'd stick with Python and Django (or AppEngine) for the moment, until you can grasp some of the more advance concepts. Then, by all means, learning new languages will be fantastic.

As for moving to Django from AppEngine. There isn't a whole lot that's different. The way you define models is similar, but has different types for the definition. As you mentioned, hosting is another consideration.

There should be plenty of hosting options (mod_wsgi is what you're after) based on Apache. Django in particular has seen quite a bit of popularity, and hosting usually springs up for popular frameworks.

I don't think you'll need to know too much sysadmin stuff. This will all depend on the kind of hosting you can find. Same goes for the database. Hosting providers usually offer databases preconfigured so you shouldn't need to worry about that too much.

Django, along with many other frameworks, provide an ORM (Object Relational Mapper) which abstracts away having to write SQL, by calling methods on objects and accessing their properties. I'd advise learning a little bit of SQL to understand it at a bare minimum though.

The Django tutorial is excellent! If you decide to go the Django route, I'd highly recommend working through the entire thing. A development server comes bundled, so you can try out your work instantly without worrying about a provider. Once you have something you want to share with the world, you can worry about hosting then.

I started off using Windows for Django development and it was quite easy. The amount of command line work you need to do is minimal. Really. Not something you need to worry about, as the tutorial covers all 4 or so commands you need to know.

Django hosting provides links to hosting providers, though I'm not sure how up to date that list is.

Getting started in Django is pretty simple. Once you want to host it, there's a bit more work involved - but that can come later. The friction is minimal. Follow the tutorial, it will take you through running the server, setting up the database (a free one comes bundled), and coding your first app.

What makes you think you're being locked into a single platform? Did you know that Google's App Engine SDK is open source? Also, there are universities and other organizations who are working on building platforms that will use the App Engine SDK outside of the context of Google? Amazon EC2 is also capable of running App Engine's SDK in a limited capacity. I'd say lock-in is perhaps not the right word to use.

Additionally, I believe AppEngine is going to continue to improve as time goes on. Google is the leader of the Internet; they've done great things and will continue to do so. I believe that anyone who sticks with their platform as a service will experience these great benefits in the years to come.

If your reasoning for moving is purely academic, I'd suggest starting a new project. Moving off of AppEngine's SDK is similar to switching from one framework to another on an already-built application. Like with any framework or platform, there are dependencies that must be dealt with in order to successfully migrate the app from platform A to platform B.

django-nonrel makes it possible to run Django on Google AppEngine: http://www.allbuttonspressed.com/projects/django-nonrel

Beside that there exists a couple of cloud offers like djangy https://www.djangy.com/

With both options you can focus on Django and Python programming and don't have to care about the sysadmin stuff.

On the django homepage there is a very good tutorial to get started with django development: http://docs.djangoproject.com/en/1.2/intro/tutorial01/

What are the skills I need to learn to get up and running with full django/python?

The question can't easily be answered because you haven't described the app. You have to actually write down the technology stack -- in detail -- or you'll never know what skills you need.

The skill list mostly comes from your technology choices. So write down your technology choices. (That's part of configuration management, an important skill you'll need if you move away from GAE.)

Since you've chosen to talk about yourself and not your technology choices, I can only guess what technologies you're using and what skills you'll need.

Here's a common technology stack.

Technically, the OS doesn't matter. Most hosting environments use open source GNU/Linux because the licensing is inexpensive. You, too, can do this. You can start with VMWare and download a nice Linux distro. Or, you can buy a very cheap PC and install Linux directly from a DVD image that you can download and burn.

My company demands that I use the Windows PC they give me. So I develop in Windows and test in VMWare Linux (Fedora 14, actually)

To learn Linux, start with a download and install. Then find a tutorial. Then stop using Windows and learn by doing. Flipping back and forth between Windows and Linux is difficult. I can do it because I don't know Windows very well. I treat Windows as a hyper-complex IDE with all kinds of non-standard, non-POSIX quirks that I try to ignore.
RDBMS. Python comes with SQLite. For a lot of applications, it works fine. It works because web sites tend to be heavy on queries and light on updates/inserts, so SQLite works well. MySQL is nice. It's easy to install and runs on Windows as well as other OS's.

The good thing about Django is you need to know very little SQL. Very little.

However, you do need to know a tiny bit about the "Data Control Language" (Grant, Revoke and Create User) to work with MySQL. You won't create a lot of users. But you do need to create a few to get things running. Also, as your database matures, you'll often need to know a little bit about the "Data Definition Language" (Drop Table).

You will need to know how to backup and restore your database. That's absolutely critical.

So find Database Administrator tutorials to get started.

If your application really uses a lot of sophisticated data, you'll need to buy real books on database design so you can understand how the Django models really work. You don't need to become a SQL guru, but it does help to know what's really going on inside the database.
Application Server. We use Apache with the mod_wsgi module. There are numerous choices. Hosting services vary in what they require and what they permit. Some have Apache, mod_wsgi and Django pre-configured. Some don't. Some do not permit tinkering with the Apache configuration. Some do. You probably don't need to know much about this, because you can probably find a hosting service that will handle the details.

Apache tutorials are all over the place. mod_wsgi is very simple; once you understand how Apache works, mod_wsgi is obvious.
Since you have stuff working, presumably you know about HTML and CSS. Those are important skills, but you probably already have them.
Since you have stuff working, you also might know a lot about Configuration Management and how to control change. This isn't obvious and many people do it wrong. If you don't know about CM, you should find some books or articles on configuration management and change control.
Since you have stuff working, you also might know a lot about quality assurance, unit testing and related topics. If you don't have a complete suite of unit tests, you should probably start learning about unit testing before you start any serious coding for the next release of your product.
Bug Tracking, Problem Reporting, Feature Requests and other management skills are also essential. I can't tell if you have them or don't have them. Or what tools you're using for this. If you're working by yourself, you don't need a lot of formality. However, these are critical skills even if you're a one-person developer. Sticky-Notes on your workstation can work. What's important is the skills to manage bugs and features.

Hey Tom, I suggest the reasonable evaluation you can make is carefully list the advantages and disadvantages of the choices.

The way I don't regret taking was physical rack server (2006-07), moved to virtual hosting (2008) and now moved to GAE (2009-current). Seeing the rate new features get added to GAE and the costeffectiveness are more reasons to stay. I agree more stuff django can are needed like in my case form preview and form validation with GAE are difficult or too difficult to set up.

I tried RoR and soon thought RoR requires more code to do the same GAE can with less code. Also with GAE you have absolutely no hardware that can break. If you move to a rack server or a virtual hosting where there are places you can get 5 GB hosting for free but you don't have a plan when you run out of 5 GB and may need to migrate again which you don't want.

MySQL has been around for over 10 years and is quite a different kind of system. It's possible to save blobs in MySQL but don't you think the blobstore GAE has is much better?

If you choose to migrate to a solution with MySQL you can export you data from GAE and import it to MySQL with a tool such as approcket.

Kind regards/Niklas R