Is there a list somewhere of recommendations of different Python-based REST frameworks for use on the serverside to write your own RESTful APIs? Preferably with pros and cons.
Something to be careful about when designing a RESTful API is the conflation of GET and POST, as if they were the same thing. It’s easy to make this mistake with Django‘s function-based views and CherryPy‘s default dispatcher, although both frameworks now provide a way around this problem (class-based views and MethodDispatcher, respectively).
Some frameworks that get it right are web.py, Flask and Bottle. When combined with the mimerender library (full disclosure: I wrote it), they allow you to write nice RESTful webservices:
import web
import json
from mimerender import mimerender
render_xml = lambda message: '<message>%s</message>'%message
render_json = lambda **args: json.dumps(args)
render_html = lambda message: '<html><body>%s</body></html>'%message
render_txt = lambda message: message
urls = (
'/(.*)', 'greet'
)
app = web.application(urls, globals())
class greet:
@mimerender(
default = 'html',
html = render_html,
xml = render_xml,
json = render_json,
txt = render_txt
)
def GET(self, name):
if not name:
name = 'world'
return {'message': 'Hello, ' + name + '!'}
if __name__ == "__main__":
app.run()
The service’s logic is implemented only once, and the correct representation selection (Accept header) + dispatch to the proper render function (or template) is done in a tidy, transparent way.
Update (April 2012): added information about Django’s class-based views, CherryPy’s MethodDispatcher and Flask and Bottle frameworks. Neither existed back when the question was asked.
Note that — out of the box — Django did not have fine-grained enough authentication for our needs. We used the Django-REST interface, which helped a lot. [We’ve since rolled our own because we’d made so many extensions that it had become a maintenance nightmare.]
We have two kinds of URL’s: “html” URL’s which implement the human-oriented HTML pages, and “json” URL’s which implement the web-services oriented processing. Our view functions often look like this.
def someUsefulThing( request, object_id ):
# do some processing
return { a dictionary with results }
def htmlView( request, object_id ):
d = someUsefulThing( request, object_id )
render_to_response( 'template.html', d, ... )
def jsonView( request, object_id ):
d = someUsefulThing( request, object_id )
data = serializers.serialize( 'json', d['object'], fields=EXPOSED_FIELDS )
response = HttpResponse( data, status=200, content_type='application/json' )
response['Location']= reverse( 'some.path.to.this.view', kwargs={...} )
return response
The point being that the useful functionality is factored out of the two presentations. The JSON presentation is usually just one object that was requested. The HTML presentation often includes all kinds of navigation aids and other contextual clues that help people be productive.
The jsonView functions are all very similar, which can be a bit annoying. But it’s Python, so make them part of a callable class or write decorators if it helps.
This emphasizes what I really like about CherryPy; this is a completely working example that’s very understandable even to someone who doesn’t know the framework. If you run this code, then you can immediately see the results in your web browser; e.g. visiting http://localhost:8080/celc_to_fahr?degrees=50 will display 122.0 in your web browser.
I don’t see any reason to use Django just to expose a REST api, there are lighter and more flexible solutions. Django carries a lot of other things to the table, that are not always needed. For sure not needed if you only want to expose some code as a REST service.
My personal experience, fwiw, is that once you have a one-size-fits-all framework, you’ll start to use its ORM, its plugins, etc. just because it’s easy, and in no time you end up having a dependency that is very hard to get rid of.
Choosing a web framework is a tough decision, and I would avoid picking a full stack solution just to expose a REST api.
Now, if you really need/want to use Django, then Piston is a nice REST framework for django apps.
That being said, CherryPy looks really nice too, but seems more RPC than REST.
Looking at the samples (I never used it), probably web.py is the best and cleanest if you only need REST.
In particular it mentions a built in CherryPy dispatcher called MethodDispatcher, which invokes methods based on their HTTP-verb identifiers (GET, POST, etc…).
In 2010, the Pylons and repoze.bfg communities “joined forces” to create Pyramid, a web framework based most heavily on repoze.bfg. It retains the philosophies of its parent frameworks, and can be used for RESTful services. It’s worth a look.
Seems all kinds of python web frameworks can implement RESTful interfaces now.
For Django, besides tastypie and piston, django-rest-framework is a promising one worth to mention. I’ve already migrated one of my project on it smoothly.
Django REST framework is a lightweight REST framework for Django, that
aims to make it easy to build well-connected, self-describing RESTful
Web APIs.
Quick example:
from django.conf.urls.defaults import patterns, url
from djangorestframework.resources import ModelResource
from djangorestframework.views import ListOrCreateModelView, InstanceModelView
from myapp.models import MyModel
class MyResource(ModelResource):
model = MyModel
urlpatterns = patterns('',
url(r'^$', ListOrCreateModelView.as_view(resource=MyResource)),
url(r'^(?P<pk>[^/]+)/$', InstanceModelView.as_view(resource=MyResource)),
)
Take the example from official site, all above codes provide api, self explained document(like soap based webservice) and even sandbox to test a bit. Very convenience.
web2py includes support for easily building RESTful API’s, described here and here (video). In particular, look at parse_as_rest, which lets you define URL patterns that map request args to database queries; and smart_query, which enables you to pass arbitrary natural language queries in the URL.
I you are using Django then you can consider django-tastypie as an alternative to django-piston. It is easier to tune to non-ORM data sources than piston, and has great documentation.
