Merge lp:~leonardr/lazr.restful/django-helpers into lp:lazr.restful

[Leonard Richardson]

[Leonard Richardson (leonardr)]

This branch adds a tiny ZCML snippet to frameworks/django.zcml that makes Django "object not found" exceptions show up in the web service as 404 errors.

The biggest part of this code is the test, which creates a temporary fake Django module hierarchy. This is based on code Gary gave me, and the code should work whether or not Django is installed.

[Barry Warsaw (barry)]

Looks good to me. As we talked about in IRC, it would be good to register the same kind of view on zope.publisher.interfaces.NotFound so that custom hacks in handleException aren't necessary.

review: Approve (code)

[Gary Poster (gary)]

On Aug 17, 2009, at 4:45 PM, Leonard Richardson wrote:
>
> +Finally, if fake Django modules were created for this test, clean
> them
> +up.
> +
> + >>> if not django_present:
> + ... del(django)

Oops, sorry, I wasn't clear.

This doesn't do anything important.

You need to delete all the keys that you stuffed into sys.modules.
That's the more important bit (to the degree that this clean up is
important at all).

Gary

[Barry Warsaw (barry)]

>
> On Aug 17, 2009, at 4:45 PM, Leonard Richardson wrote:
> >
> > +Finally, if fake Django modules were created for this test, clean
> > them
> > +up.
> > +
> > + >>> if not django_present:
> > + ... del(django)
>
> Oops, sorry, I wasn't clear.
>
> This doesn't do anything important.
>
> You need to delete all the keys that you stuffed into sys.modules.
> That's the more important bit (to the degree that this clean up is
> important at all).

It's probably not. It can't hurt, but you're right it probably doesn't help at all either. Might as well remove that code since it's just test framework noise.

=== modified file 'src/lazr/restful/NEWS.txt'
--- src/lazr/restful/NEWS.txt	2009-08-17 16:22:22 +0000
+++ src/lazr/restful/NEWS.txt	2009-08-17 20:24:58 +0000
@@ -2,6 +2,13 @@
 NEWS for lazr.restful
 =====================
 
+Development
+===========
+
+For services that use Django, added an adapter from Django's
+ObjectDoesNotExist to lazr.restful's NotFoundView.
+
+
 0.9.4 (2009-08-17)
 ==================
 
 
=== modified file 'src/lazr/restful/docs/django.txt'
--- src/lazr/restful/docs/django.txt	2009-08-14 20:25:45 +0000
+++ src/lazr/restful/docs/django.txt	2009-08-17 20:24:58 +0000
@@ -68,12 +68,14 @@
 between IDjangoLocation and ILocation. We'll load it.
 
     >>> from zope.configuration import xmlconfig
-    >>> zcmlcontext = xmlconfig.string("""
+    >>> def load_django_config():
+    ...     xmlconfig.string("""
     ... <configure xmlns="http://namespaces.zope.org/zope">
     ...   <include package="lazr.restful" file="basic-site.zcml" />
     ...   <include package="lazr.restful.frameworks" file="django.zcml" />
     ... </configure>
     ... """)
+    >>> load_django_config()
 
 Now it's possible to adapt a Django model object to ILocation and
 check on its __name__.
@@ -92,3 +94,79 @@
     >>> request = Request("", {})
     >>> print str(getMultiAdapter((resource, request), IAbsoluteURL))
     http://dummy/myname
+
+
+ObjectNotFound
+==============
+
+The django.zcml helper file contains an adapter registration so that
+Django's ObjectDoesNotExist exceptions are treated as 404 errors.
+
+Since lazr.restful does not depend on Django, this test needs to work
+whether or not Django is installed. If Django is installed, the
+following code does nothing. If Django is not installed, this code
+creates a fake django.core.exceptions.ObjectDoesNotExist class that
+lazr.restful can use.
+
+    >>> django_present = False
+    >>> try:
+    ...     from django.core.exceptions import ObjectDoesNotExist
+    ...     django_present = True
+    ... except ImportError:
+    ...     class ObjectDoesNotExist(Exception):
+    ...         pass
+    ...
+    ...     import sys
+    ...     import types
+    ...     previous = None
+    ...     previous_names = []
+    ...
+    ...     for module_name in 'django.core.exceptions'.split('.'):
+    ...         previous_names.append(module_name)
+    ...         full_name = '.'.join(previous_names)
+    ...         module = types.ModuleType(full_name)
+    ...         if previous is not None:
+    ...             setattr(previous, module_name, module)
+    ...         previous = module
+    ...         sys.modules[module_name] = module
+    ...
+    ...     import django.core.exceptions
+    ...     django.core.exceptions.ObjectDoesNotExist = ObjectDoesNotExist
+
+Now we can act as though this portion of Django was installed.
+
+    >>> from django.core.exceptions import ObjectDoesNotExist
+    >>> exception = ObjectDoesNotExist()
+
+Reload the Zope configuration so it'll know about the new class.
+
+    >>> load_django_config()
+
+Register a simple IWebServiceConfiguration so that the error view will
+run correctly.
+
+    >>> from lazr.restful.interfaces import IWebServiceConfiguration
+    >>> class SimpleWebServiceConfiguration:
+    ...     implements(IWebServiceConfiguration)
+    ...     show_tracebacks = False
+    >>> webservice_configuration = SimpleWebServiceConfiguration()
+    >>> sm.registerUtility(webservice_configuration)
+
+That was a lot of work, but now we can instantiate an
+ObjectDoesNotExist and then get a view for it.
+
+    >>> view = getMultiAdapter((exception, request), name="index.html")
+    >>> view()
+    ''
+
+The view for the ObjectDoesNotExist exception sets the HTTP response
+code to 404.
+
+    >>> request.response.getStatus()
+    404
+
+Finally, if fake Django modules were created for this test, clean them
+up.
+
+    >>> if not django_present:
+    ...    del(django)
 
=== modified file 'src/lazr/restful/frameworks/django.zcml'
--- src/lazr/restful/frameworks/django.zcml	2009-08-14 18:33:04 +0000
+++ src/lazr/restful/frameworks/django.zcml	2009-08-17 16:51:25 +0000
@@ -20,4 +20,17 @@
       factory="zope.traversing.browser.absoluteurl.AbsoluteURL"
       />
 
-</configure>
 \ No newline at end of file
+  <!--We want a raised django.core.exceptions.ObjectDoesNotExist
+      object to result in a 404 status code. But we don't
+      control that class definition, so we can't annotate it.
+      Instead, we define an adapter from that exception class to the
+      NotFoundView.-->
+  <adapter
+      for="django.core.exceptions.ObjectDoesNotExist
+           lazr.restful.interfaces.IWebServiceClientRequest"
+      provides="zope.interface.Interface"
+      factory="lazr.restful.error.NotFoundView"
+      name="index.html"
+      />
+
+</configure>