On Mar 10, 2009, at 12:43 AM, [email protected] wrote:
>
> I'm trying to build a combined feed, and not having much luck. Here's
> what I have:
>
> class CombinedFeed(Feed):
> title = site.name +" combined feed"
> link = "/"
> description = "Latest updates from all "+site.name +" feeds"
> description_template = 'feeds/combined.html'
>
> def items(self):
> combined = []
> articles = Article.objects.all().order_by('-created')[:
> 40]
> events =
> Event.objects.filter(start_date__gte=now).order_by
> ('start_date')[:50]
> news =
> News_item.objects.filter(pub_date__lte=now).order_by('-
> pub_date')[:20]
> combined = itertools.chain(news, articles, projects,
> issues,
> events)
> for item in combined:
> try:
> item.date = item.created
> except:
> try:
> item.date = item.topic_modification_date
> except:
> try:
> item.date = item.pub_date
> except:
> try:
> item.date = item.start_date
> except:
> item.date = now
> return combined
Itertools.chain returns a generator. Once you've run through the
generator a single time (as you're doing with "for item in combined")
it's exhausted: your return statement is returning an empty iterable.
Here's how I do something similar with one of my feeds:
def items(self):
el = list(Entry.objects.open()[:10])
el
.extend(list(NewsLink.objects.filter(post_date__gte=el[-1].disp_date)))
el.sort(key=lambda x: getattr(x, x._meta.ordering[0].strip('-')),
reverse=True)
return el
I've just decided that there aren't enough items to fret about calling
list() on the whole thing, and it's important to me that everything
return in proper order. If you're worried about prematurely evaluating
the querysets (though you're doing that right now!), I remember once
seeing a recipe on activestate or somewhere for a iter-style function
that took several iterables and then returned items from each iterable
in sorted order.
Also, you can avoid the whole attribute-testing chain (which would
allow you to return an un-evaluated QuerySet), by using the
_meta.ordering[0] trick to get the proper attribute name. Or specify
the proper date attribute using a python-only attribute on each model.
I do something similar to specify different templates to use for
different models when rendering the feed: each model has a non-db
'feed_template' string attribute.
Hope something in there is useful,
Eric
>
>
> Which doesn't appear to do anything. No error, but no ojb in
> combined.html, either.
> Suggestions?
> >
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