From f86e54e3b0520fa954e1cabbf67752ef9b99c78f Mon Sep 17 00:00:00 2001 From: Malcolm Tredinnick Date: Thu, 29 Nov 2007 17:41:35 +0000 Subject: [PATCH] Added better error handling in the basic feed class example. Refs #5855 git-svn-id: http://code.djangoproject.com/svn/django/trunk@6741 bcc190cf-cafb-0310-a4f2-bffc1f526a37 --- docs/syndication_feeds.txt | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/docs/syndication_feeds.txt b/docs/syndication_feeds.txt index 30943591b8..2eb188a737 100644 --- a/docs/syndication_feeds.txt +++ b/docs/syndication_feeds.txt @@ -201,6 +201,8 @@ the feed. An example makes this clear. Here's the code for these beat-specific feeds:: + from django.contrib.syndication import FeedDoesNotExist + class BeatFeed(Feed): def get_object(self, bits): # In case of "/rss/beats/0613/foo/bar/baz/", or other such clutter, @@ -213,6 +215,8 @@ An example makes this clear. Here's the code for these beat-specific feeds:: return "Chicagocrime.org: Crimes for beat %s" % obj.beat def link(self, obj): + if not obj: + raise FeedDoesNotExist return obj.get_absolute_url() def description(self, obj): @@ -246,11 +250,18 @@ request to the URL ``/rss/beats/0613/``: each of ``title``, ``link`` and ``description``, Django follows this algorithm: - * First, it tries to call a method, passing the ``obj`` argument, where - ``obj`` is the object returned by ``get_object()``. + * First, it tries to call a method, passing the ``obj`` argument, + where ``obj`` is the object returned by ``get_object()``. * Failing that, it tries to call a method with no arguments. * Failing that, it uses the class attribute. + Inside the ``link()`` method, we handle the possibility that ``obj`` + might be ``None``, which can occur when the URL isn't fully specified. In + some cases, you might want to do something else in this case, which would + mean you'd need to check for ``obj`` existing in other methods as well + (the ``link()`` method is called very early in the feed generation + process, so is a good place to bail out early). + * Finally, note that ``items()`` in this example also takes the ``obj`` argument. The algorithm for ``items`` is the same as described in the previous step -- first, it tries ``items(obj)``, then ``items()``, then