REST support in Grok

P. Wilson : Began review process.

 * Can see error already with old style REST suppot via

 class AtomPubProtocol(grok.RESTProtocol):
    grok.layer(AtomPubLayer)
    grok.name('atompub') # a nicer name

whereas the Grok changelog states that:

"Similar to the layers and skins restructuring, the grok.RESTProtocol baseclass has been removed in favour of a grok.restskin(name) directive that can be used on REST layer interfaces. Introduced the IRESTLayer base interfaces for defining REST layers."

Fixing the example requires removing the above class and adding:

grok.restskin('rest')

to the AtomPubLayer defined.

Additional Thoughts
==============

* A more realistic example where headers are correctly set might be useful.

* Would be useful to show the doctest update required to test this rest interface, e.g.:

~~~~~~~~~~~~%<~~~~~~~~~~~~~
Do a functional doctest test on the app.
========================================

:Test-Layer: functional

Let's first create an instance of Grok_doc_tests at the top level:

   >>> from grok_doc_tests.app import Grok_doc_tests, MyContainer
   >>> root = getRootFolder()
   >>> root['app'] = Grok_doc_tests()
   >>> root['app']['container'] = MyContainer()

Run tests in the testbrowser
----------------------------

The zope.testbrowser.browser module exposes a Browser class that
simulates a web browser similar to Mozilla Firefox or IE. We use that
to test how our application behaves in a browser. For more
information, see http://pypi.python.org/pypi/zope.testbrowser.

Create a browser and visit the instance you just created:

   >>> from zope.testbrowser.testing import Browser
   >>> browser = Browser()
   >>> browser.open('http://localhost/++rest++rest/app/container')

Check some basic information about the page you visit:

   >>> browser.url
   'http://localhost/++rest++rest/app/container'
   >>> browser.headers.get('Status').upper()
   '200 OK'
~~~~~~~~~~~~%<~~~~~~~~~~~~~

* Can see possibility for expansion to cover applying default skins to remove ++rest++:

@grok.subscribe( ... , grok.IBeforeTraverseEvent)
def restSkin(obj, event):
   if not RestAPILayer.providedBy(event.request):
      grok.util.applySkin(event.request, RestAPILayer, grok.IRestSkinType)

14th October 2009 - JW-Kolman requests expansion to detail how applying skins automatically affects requests to all subobjects of the traversed skinned object.