Develop Reference

Python REST frameworks for App Engine?

Any pointers, advice on implementing a REST API on App Engine with Python? Using webapp for the application itself.
What I currently know is that I can:
hack up my own webapp handlers for handling REST-like URIs, but this seems to lose its elegance for larger amounts of resources. I mean, it's simple when it comes to temperature/atlanta, but not so much* for even a rather simple /users/alice/address/work (though do keep in mind that I'm not saying this after having implemented that, just after spending some time trying to design an appropriate handler, so my perception may be off).
use the REST functionality provided by one of the bigger Python web frameworks out there. I have some unexplainable sympathy towards web2py, but, since it's not used for the project, bundling it with the application just to provide some REST functionality seems.. overkill?
(Huh, looks like I don't like any of these approaches. Tough.)
So here's me asking: what advice, preferably based on experience, would you have for me here? What are my options, is my view of them correct, did I miss something?
Thanks in advance.

I had a similar issue. Wanting to quickly get my DataStore exposed via REST to WebApps.
Found: AppEngine REST Server.
I have only used it lightly so far, but it certainly appears to be very useful with a small amount of work. And it does use webapp as you suggested.

ProtoRPC is bundled with the SDK, and it is robust and actively developed (however experimental). Although I think the source code itself is a little convoluted, the feature-set is pretty complete and it was made by someone with experience in creating this kind of library. It supports transmiting using JSON, ProtocolBuffer and URL-encoded formats.
Also, you can create APIs that work on the server side and client side -- it defines a 'message' protocol with implementations in Python and JavaScript. I used other "RESTful" Python libraries, but no other provided this consistency out of the box.
Here is the project page and here is the mailing list.
Edit: maybe their documentation is lacking some keywords, but just to be clear: one or the purposes of ProtoRPC is to provide a solid foundation to create REST services.

Creating a python web server to recieve XML HTTP Requests

I am currently working on a project to create simple file uploader site that will update the user of the progress of an upload.
I've been attempting this in pure python (with CGI) on the server side but to get the progress of the file I obviously need send requests to the server continually. I was looking to use AJAX to do this but I was wondering how hard it would be to, instead of changing to some other framerwork (web.py for instance), just write my own web server for receiving the XML HTTP Requests?
My main problem is that sending the request is done from HTML and Javascript so it all seems like magic trickery at the moment.
Can anyone advise me as to the best way to go about receiving these requests on the server?
EDIT: It seems that a framework would be the way to go. Would web.py be a good route to take?

I would recommend to use a microframework like Sinatra for Ruby. There seem to be some equivalents for Python. What python equivalent of Sinatra would you recommend?
Such a framework allows you to simply map a single method to a route.

Writing a very basic HTTP server won't be very hard (see http://docs.python.org/library/simplehttpserver.html for an example), but you will be missing many features that are provided by real servers and web frameworks.
For your project, I suggest you pick one of the many Python web frameworks and run your application behind Apache/mod_wsgi.

There's absolutely no need to write your own web server. Plenty of options exist, including lightweight ones like nginx.
You should use one of those, and either your own custom WSGI code to receive the request, or (better) one of the microframeworks like Flask or Bottle.

Reading request parameters in Python

I am very new to python and having to get into this stuff for a simple program to integrate with an ASP.NET application that I am building. The pseudo code is as follows.
Get two parameters from request. (A ASP.NET will be calling this url by POST and sending two parameters)
Internally execute some business logic and build some response.
Write the response back so that the ASP.NET app can proceed.
Step 2 and 3 are already in place and working too but not able to find a solution for Step 1 (I know it should be very simple and know how to do it in Java/.NET/PHP and RoR but not in Python and the online docs/tutorials are not helping my cause). I am running python on apache using mod_python.
Any help here is greatly appreciated. Thanks in advance
Vijay

Here is a good beginner's tutorial for mod_python.
As far as I understand your question you have a mod_python-based script and you want to read a POST parameter. Therefore you only have to use the form object which is automatically provided by mod_python:
myparameter = form.getfirst("name_of_the_post_parameter")
You can find the documentation over here.
Note that this solution is when your server is configured with PythonHandler mod_python.psp which will allow you to use "Python Server Pages" (special <% %> tags, automatically created variables like form, ...). If you're writing a normal mod_python handler, then it would look something like that:
from mod_python import util
def handler(req):
form = util.FieldStorage(req, keep_blank_values=1)
myparameter = form.getfirst("name_of_the_post_parameter")
...other stuff...

"I know it should be very simple and know how to do it in Java/.NET/PHP and RoR but not in Python"
Well, it's not simple in Python -- the language.
It is simple in many Python web frameworks.
Don't make the mistake of comparing Python (the language) with PHP (the web framework) or RoR (the web framework).
Python, like Java or VB or Ruby, is a programming language. Not a web framework.
To get stuff from Apache into Python you have three choices.
A CGI script. A dreadful choice.
mod_python. Not a great choice.
mod_wsgi. A much better choice.
If you're stuck with mod_python -- because this is homework, for instance -- you'll need to read a mod_python tutorial in addition to a python tutorial.
This, for example, seems to be what you're doing. http://www.modpython.org/live/current/doc-html/tut-pub.html

Writing a website in Python

I'm pretty proficient in PHP, but want to try something new.
I'm also know a bit of Python, enough to do the basics of the basics, but haven't used in a web design type situation.
I've just written this, which works:
#!/usr/bin/python
def main():
print "Content-type: text/html"
print
print "<html><head>"
print "<title>Hello World from Python</title>"
print "</head><body>"
print "Hello World!"
print "</body></html>"
if __name__ == "__main__":
main()
Thing is, that this seems pretty cumbersome. Without using something huge like django, what's the best way to write scripts that can process get and post?

Your question was about basic CGI scripting, looking at your example, but it seems like everyone has chosen to answer it with "use my favorite framework". Let's try a different approach.
If you're looking for a direct replacement for what you wrote above (ie. CGI scripting), then you're probably looking for the cgi module. It's a part of the Python standard library. Complimentary functionality is available in urllib and urllib2. You might also be interested in BaseHTTPServer and SimpleHTTPServer, also part of the standard library.
Getting into more interesting territory, wsgiref gives you the basics of a WSGI interface, at which point you probably want to start thinking about more "frameworky" (is that a word?) things like web.py, Django, Pylons, CherryPy, etc, as others have mentioned.

As far as full frameworks go I believe Django is relatively small.
If you really want lightweight, though, check out web.py, CherryPy, Pylons and web2py.
I think the crowd favorite from the above is Pylons, but I am a Django man so I can't say much else.
For more on lightweight Python frameworks, check out this question.

There are a couple of web frameworks available in python, that will relieve you from most of the work
Django
Pylons (and the new TurboGears, based on it).
Web2py
CherryPy (and the old TurboGears, based on it)
I do not feel Django as "big" as you say; however, I think that Pylons and CherryPy may be a better answer to your question. CherryPy seems simpler,. but seems also a bit "passé", while Pylons is under active development.
For Pylons, there is also an interesting Pylons book, available online.

In Python, the way to produce a website is to use a framework. Most of the popular (and actively maintained/supported) frameworks have already been mentioned.
In general, I do not view Djano or Turbogears as "huge", I view them as "complete." Each will let you build a database backed, dynamic website. The preference for one over the other is more about style than it is about features.
Zope on the other hand, does feel "big". Zope is also "enterprise" class in terms of the features that are included out of the box. One very nice thing is that you can use the ZODB (Zope Object Database) without using the rest of Zope.
It would certainly help if we knew what kinds of websites you were interested in developing, as that might help to narrow the suggestions.

In web2py the previous code would be
in controller default.py:
def main():
return dict(message="Hello World")
in view default/main.html:
<html><head>
<title>Hello World from Python</title>
</head><body>
{{=message}}
</body></html>
nothing else, no installation, no configuration, you can edit the two files above directly on the web via the admin interface. web2py is based on wsgi but works also with cgi, mod_python, mod_proxy and fastcgi if mod_wsgi is not available.

I really love django and it doesn't seem to me that is huge. It is very powerful but not huge.
If you want to start playing with http and python, the simplest thing is the BaseHttpServer provided in the standard library. see http://docs.python.org/library/basehttpserver.html for details

I agree with Paolo - Django is pretty small and the way to go - but if you are not down with that I would add to TurboGears to the list

If you are looking for a framework take a look at this list: Python Web Frameworks
If you need small script(-s) or one time job script, might be plain CGI module is going to be enough - CGI Scripts and cgi module itself.
I would recommend you to stick to some framework if you want to create something more then static pages and simple forms. Django is I believe most popular and most supported.

What is "huge" is a matter of taste, but Django is a "full stack" framework, that includes everything from an ORM, to templates to well, loads of things. So it's not small (although smaller than Grok and Zope3, other full-stack python web frameworks).
But there are also plenty of really small and minimalistic web frameworks, that do nothing than provide a framework for the web part. Many have been mentioned above. To the list I must add BFG and Bobo. Both utterly minimal, but still useful and flexible.
http://bfg.repoze.org/
http://bobo.digicool.com/

Python web server?

I want to develop a tool for my project using python. The requirements are:
Embed a web server to let the user get some static files, but the traffic is not very high.
User can configure the tool using http, I don't want a GUI page, I just need a RPC interface, like XML-RPC? or others?
Besides the web server, the tool need some background job to do, so these jobs need to be done with the web server.
So, Which python web server is best choice? I am looking at CherryPy, If you have other recommendation, please write it here.

what about the internal python webserver ?
just type "python web server" in google, and host the 1st result...

Well, I used web frameworks like TurboGears, my current projects are based on Pylons. The last ist fairly easy to learn and both come with CherryPy.
To do some background job you could implement that in pylons too.
Just go to your config/environment.py and see that example:
(I implemented a queue here)
from faxserver.lib.myQueue import start_queue
...
def load_environment(global_conf, app_conf):
...
start_queue()
It depends on your need if you simply use CherryPy or start to use something more complete like Pylons.

Use the WSGI Reference Implementation wsgiref already provided with Python
Use REST protocols with JSON (not XML-RPC). It's simpler and faster than XML.
Background jobs are started with subprocess.

Why dont you use open source build tools (continuous integration tools) like Cruise. Most of them come with a web server/xml interface and sometimes with fancy reports as well.

This sounds like a fun project. So, why don't write your own HTTP server? Its not so complicated after all, HTTP is a well-known and easy to implement protocol and you'll gain a lot of new knowledge!
Check documentation or manual pages (whatever you prefer) of socket(), bind(), listen(), accept() and so on.