Issues in commit 146 (twisted)

Had put these as comments in the merge request, but as it's already been merged, opening a bug...

There's a missing call to request.finish() in render_GET in ImageResource

        request.write(json.dumps([i.metadata for i in images]))
+ request.finish()
        return server.NOT_DONE_YET

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There's what looks like a typo bug in line 537:
images = [i for i in image.Image.all() if i.is_authorized(self.context)]

Should probably be...
images = [i for i in image.Image.all() if i.is_authorized(request.context)]

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Some issues inherited from the old code, but this is probably the time to clean it up:

1) If the Authorization header is not set, this throws a 500 error, where it should raise exception.NotAuthorized (401?)
Presumably the except clause needs to be broader than "except exception.Error, ex:"

2) Should we be using the 'modern' exception syntax "exception exception.Error as ex"?
http://www.python.org/dev/peps/pep-3110/

3) There's a pretty big FIXME in there "# FIXME: check signature here!" - should we should open a separate bug for that?