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Completely refactored legacy RSS framework to the new django.contrib.syndication package. Also added Atom support, changed the way feeds are registered and added documentation for the whole lot. This is backwards-incompatible, but the RSS framework had not yet been documented, so this should only affect tinkerers and WorldOnline. Fixes #329, #498, #502 and #554. Thanks for various patches/ideas to alastair, ismael, hugo, eric moritz and garthk 

git-svn-id: http://code.djangoproject.com/svn/django/trunk@1194 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Adrian Holovaty 2005-11-12 03:44:53 +00:00
parent e8ae356739
commit 944de9e9e6
8 changed files with 822 additions and 303 deletions
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6
django/conf/urls/rss.py
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@ -1,6 +0,0 @@
from django.conf.urls.defaults import *
urlpatterns = patterns('django.views',
(r'^(?P<slug>[^/]+)/$', 'rss.rss.feed'),
(r'^(?P<slug>[^/]+)/(?P<param>.+)/$', 'rss.rss.feed'),
)

0
django/contrib/syndication/__init__.py Normal file
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89
django/contrib/syndication/feeds.py Normal file
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@ -0,0 +1,89 @@
from django.core.exceptions import ImproperlyConfigured, ObjectDoesNotExist
from django.core.template import Context, loader, Template, TemplateDoesNotExist
from django.models.core import sites
from django.utils import feedgenerator
from django.conf.settings import LANGUAGE_CODE, SETTINGS_MODULE
def add_domain(domain, url):
if not url.startswith('http://'):
url = u'http://%s%s' % (domain, url)
return url
class FeedDoesNotExist(ObjectDoesNotExist):
pass
class Feed:
item_pubdate = None
item_enclosure_url = None
feed_type = feedgenerator.DefaultFeed
def __init__(self, slug):
self.slug = slug
def item_link(self, item):
try:
return item.get_absolute_url()
except AttributeError:
raise ImproperlyConfigured, "Give your %s class a get_absolute_url() method, or define an item_link() method in your Feed class." % item.__class__.__name__
def __get_dynamic_attr(self, attname, obj):
attr = getattr(self, attname)
if callable(attr):
try:
return attr(obj)
except TypeError:
return attr()
return attr
def get_feed(self, url=None):
"""
Returns a feedgenerator.DefaultFeed object, fully populated, for
this feed. Raises FeedDoesNotExist for invalid parameters.
"""
if url:
try:
obj = self.get_object(url.split('/'))
except (AttributeError, ObjectDoesNotExist):
raise FeedDoesNotExist
else:
obj = None
current_site = sites.get_current()
link = self.__get_dynamic_attr('link', obj)
link = add_domain(current_site.domain, link)
feed = self.feed_type(
title = self.__get_dynamic_attr('title', obj),
link = link,
description = self.__get_dynamic_attr('description', obj),
language = LANGUAGE_CODE.decode()
)
try:
title_template = loader.get_template('feeds/%s_title' % self.slug)
except TemplateDoesNotExist:
title_template = Template('{{ obj }}')
try:
description_template = loader.get_template('feeds/%s_description' % self.slug)
except TemplateDoesNotExist:
description_template = Template('{{ obj }}')
for item in self.__get_dynamic_attr('items', obj):
link = add_domain(current_site.domain, self.__get_dynamic_attr('item_link', item))
enc = None
enc_url = self.__get_dynamic_attr('item_enclosure_url', item)
if enc_url:
enc = feedgenerator.Enclosure(
url = enc_url.decode('utf-8'),
length = str(self.__get_dynamic_attr('item_enclosure_length', item)).decode('utf-8'),
mime_type = self.__get_dynamic_attr('item_enclosure_mime_type', item).decode('utf-8'),
)
feed.add_item(
title = title_template.render(Context({'obj': item, 'site': current_site})).decode('utf-8'),
link = link,
description = description_template.render(Context({'obj': item, 'site': current_site})).decode('utf-8'),
unique_id = link,
enclosure = enc,
pubdate = self.__get_dynamic_attr('item_pubdate', item),
)
return feed

26
django/contrib/syndication/views.py Normal file
View File

@ -0,0 +1,26 @@
from django.contrib.syndication import feeds
from django.core.exceptions import Http404
from django.utils.httpwrappers import HttpResponse
def feed(request, url, feed_dict=None):
if not feed_dict:
raise Http404, "No feeds are registered."
try:
slug, param = url.split('/', 1)
except ValueError:
slug, param = url, ''
try:
f = feed_dict[slug]
except KeyError:
raise Http404, "Slug %r isn't registered." % slug
try:
feedgen = f(slug).get_feed(param)
except feeds.FeedDoesNotExist:
raise Http404, "Invalid feed parameters. Slug %r is valid, but other parameters, or lack thereof, are not." % slug
response = HttpResponse(mimetype='application/xml')
feedgen.write(response, 'utf-8')
return response

223
django/core/rss.py
View File

@ -1,223 +0,0 @@
from django.core.exceptions import ImproperlyConfigured, ObjectDoesNotExist
from django.core.template import Context, loader, Template, TemplateDoesNotExist
from django.models.core import sites
from django.utils import feedgenerator
from django.conf.settings import LANGUAGE_CODE, SETTINGS_MODULE
def add_domain(domain, url):
if not url.startswith('http://'):
url = u'http://%s%s' % (domain, url)
return url
class FeedDoesNotExist(ObjectDoesNotExist):
pass
class Feed:
item_pubdate = None
item_enclosure_url = None
def item_link(self, item):
try:
return item.get_absolute_url()
except AttributeError:
raise ImproperlyConfigured, "Give your %s class a get_absolute_url() method, or define an item_link() method in your RSS class." % item.__class__.__name__
def __get_dynamic_attr(self, attname, obj):
attr = getattr(self, attname)
if callable(attr):
try:
return attr(obj)
except TypeError:
return attr()
return attr
def get_feed(self, url=None):
"""
Returns a feedgenerator.DefaultRssFeed object, fully populated, for
this feed. Raises FeedDoesNotExist for invalid parameters.
"""
if url:
try:
obj = self.get_object(url.split('/'))
except (AttributeError, ObjectDoesNotExist):
raise FeedDoesNotExist
else:
obj = None
current_site = sites.get_current()
link = self.__get_dynamic_attr('link', obj)
link = add_domain(current_site.domain, link)
feed = feedgenerator.DefaultRssFeed(
title = self.__get_dynamic_attr('title', obj),
link = link,
description = self.__get_dynamic_attr('description', obj),
language = LANGUAGE_CODE.decode()
)
try:
title_template = loader.get_template('rss/%s_title' % self.slug)
except TemplateDoesNotExist:
title_template = Template('{{ obj }}')
try:
description_template = loader.get_template('rss/%s_description' % self.slug)
except TemplateDoesNotExist:
description_template = Template('{{ obj }}')
for item in self.__get_dynamic_attr('items', obj):
link = add_domain(current_site.domain, self.__get_dynamic_attr('item_link', item))
enc = None
enc_url = self.__get_dynamic_attr('item_enclosure_url', item)
if enc_url:
enc = feedgenerator.Enclosure(
url = enc_url.decode('utf-8'),
length = str(self.__get_dynamic_attr('item_enclosure_length', item)).decode('utf-8'),
mime_type = self.__get_dynamic_attr('item_enclosure_mime_type', item).decode('utf-8'),
)
feed.add_item(
title = title_template.render(Context({'obj': item, 'site': current_site})).decode('utf-8'),
link = link,
description = description_template.render(Context({'obj': item, 'site': current_site})).decode('utf-8'),
unique_id = link,
enclosure = enc,
pubdate = self.__get_dynamic_attr('item_pubdate', item),
)
return feed
# DEPRECATED
class FeedConfiguration:
def __init__(self, slug, title_cb, link_cb, description_cb, get_list_func_cb, get_list_kwargs,
param_func=None, param_kwargs_cb=None, get_list_kwargs_cb=None, get_pubdate_cb=None,
enc_url=None, enc_length=None, enc_mime_type=None):
"""
slug -- Normal Python string. Used to register the feed.
title_cb, link_cb, description_cb -- Functions that take the param
(if applicable) and return a normal Python string.
get_list_func_cb -- Function that takes the param and returns a
function to use in retrieving items.
get_list_kwargs -- Dictionary of kwargs to pass to the function
returned by get_list_func_cb.
param_func -- Function to use in retrieving the param (if applicable).
param_kwargs_cb -- Function that takes the slug and returns a
dictionary of kwargs to use in param_func.
get_list_kwargs_cb -- Function that takes the param and returns a
dictionary to use in addition to get_list_kwargs (if applicable).
get_pubdate_cb -- Function that takes the object and returns a datetime
to use as the publication date in the feed.
The three enc_* parameters are strings representing methods or
attributes to call on a particular item to get its enclosure
information. Each of those methods/attributes should return a normal
Python string.
"""
self.slug = slug
self.title_cb, self.link_cb = title_cb, link_cb
self.description_cb = description_cb
self.get_list_func_cb = get_list_func_cb
self.get_list_kwargs = get_list_kwargs
self.param_func, self.param_kwargs_cb = param_func, param_kwargs_cb
self.get_list_kwargs_cb = get_list_kwargs_cb
self.get_pubdate_cb = get_pubdate_cb
assert (None == enc_url == enc_length == enc_mime_type) or (enc_url is not None and enc_length is not None and enc_mime_type is not None)
self.enc_url = enc_url
self.enc_length = enc_length
self.enc_mime_type = enc_mime_type
def get_feed(self, param_slug=None):
"""
Returns a utils.feedgenerator.DefaultRssFeed object, fully populated,
representing this FeedConfiguration.
"""
if param_slug:
try:
param = self.param_func(**self.param_kwargs_cb(param_slug))
except ObjectDoesNotExist:
raise FeedIsNotRegistered
else:
param = None
current_site = sites.get_current()
f = self._get_feed_generator_object(param)
title_template = loader.get_template('rss/%s_title' % self.slug)
description_template = loader.get_template('rss/%s_description' % self.slug)
kwargs = self.get_list_kwargs.copy()
if param and self.get_list_kwargs_cb:
kwargs.update(self.get_list_kwargs_cb(param))
get_list_func = self.get_list_func_cb(param)
for obj in get_list_func(**kwargs):
link = obj.get_absolute_url()
if not link.startswith('http://'):
link = u'http://%s%s' % (current_site.domain, link)
enc = None
if self.enc_url:
enc_url = getattr(obj, self.enc_url)
enc_length = getattr(obj, self.enc_length)
enc_mime_type = getattr(obj, self.enc_mime_type)
try:
enc_url = enc_url()
except TypeError:
pass
try:
enc_length = enc_length()
except TypeError:
pass
try:
enc_mime_type = enc_mime_type()
except TypeError:
pass
enc = feedgenerator.Enclosure(enc_url.decode('utf-8'),
(enc_length and str(enc_length).decode('utf-8') or ''), enc_mime_type.decode('utf-8'))
f.add_item(
title = title_template.render(Context({'obj': obj, 'site': current_site})).decode('utf-8'),
link = link,
description = description_template.render(Context({'obj': obj, 'site': current_site})).decode('utf-8'),
unique_id=link,
enclosure=enc,
pubdate = self.get_pubdate_cb and self.get_pubdate_cb(obj) or None,
)
return f
def _get_feed_generator_object(self, param):
current_site = sites.get_current()
link = self.link_cb(param).decode()
if not link.startswith('http://'):
link = u'http://%s%s' % (current_site.domain, link)
return feedgenerator.DefaultRssFeed(
title = self.title_cb(param).decode(),
link = link,
description = self.description_cb(param).decode(),
language = LANGUAGE_CODE.decode(),
)
# global dict used by register_feed and get_registered_feed
_registered_feeds = {}
# DEPRECATED
class FeedIsNotRegistered(Exception):
pass
# DEPRECATED
def register_feed(feed):
_registered_feeds[feed.slug] = feed
def register_feeds(*feeds):
for f in feeds:
_registered_feeds[f.slug] = f
def get_registered_feed(slug):
# try to load a RSS settings module so that feeds can be registered
try:
__import__(SETTINGS_MODULE + '_rss', '', '', [''])
except (KeyError, ImportError, ValueError):
pass
try:
return _registered_feeds[slug]
except KeyError:
raise FeedIsNotRegistered

221
django/utils/feedgenerator.py
View File

@ -19,21 +19,42 @@ http://diveintomark.org/archives/2004/02/04/incompatible-rss
""" """
from django.utils.xmlutils import SimplerXMLGenerator from django.utils.xmlutils import SimplerXMLGenerator
import datetime, re, time
import email.Utils
from xml.dom import minidom
from xml.parsers.expat import ExpatError
def rfc2822_date(date):
return email.Utils.formatdate(time.mktime(date.timetuple()))
def get_tag_uri(url, date):
"Creates a TagURI. See http://diveintomark.org/archives/2004/05/28/howto-atom-id"
tag = re.sub('^http://', '', url)
if date is not None:
tag = re.sub('/', ',%s:/' % date.strftime('%Y-%m-%d'), tag, 1)
tag = re.sub('#', '/', tag)
return 'tag:' + tag
class SyndicationFeed: class SyndicationFeed:
"Base class for all syndication feeds. Subclasses should provide write()" "Base class for all syndication feeds. Subclasses should provide write()"
def __init__(self, title, link, description, language=None): def __init__(self, title, link, description, language=None, author_email=None,
self.feed_info = { author_name=None, author_link=None, subtitle=None, categories=None):
self.feed = {
'title': title, 'title': title,
'link': link, 'link': link,
'description': description, 'description': description,
'language': language, 'language': language,
'author_email': author_email,
'author_name': author_name,
'author_link': author_link,
'subtitle': subtitle,
'categories': categories or (),
} }
self.items = [] self.items = []
def add_item(self, title, link, description, author_email=None, def add_item(self, title, link, description, author_email=None,
author_name=None, pubdate=None, comments=None, unique_id=None, author_name=None, pubdate=None, comments=None,
enclosure=None, categories=None): unique_id=None, enclosure=None, categories=()):
""" """
Adds an item to the feed. All args are expected to be Python Unicode Adds an item to the feed. All args are expected to be Python Unicode
objects except pubdate, which is a datetime.datetime object, and objects except pubdate, which is a datetime.datetime object, and
@ -49,7 +70,7 @@ class SyndicationFeed:
'comments': comments, 'comments': comments,
'unique_id': unique_id, 'unique_id': unique_id,
'enclosure': enclosure, 'enclosure': enclosure,
'categories': categories or [], 'categories': categories or (),
}) })
def num_items(self): def num_items(self):
@ -71,6 +92,18 @@ class SyndicationFeed:
self.write(s, encoding) self.write(s, encoding)
return s.getvalue() return s.getvalue()
def latest_post_date(self):
"""
Returns the latest item's pubdate. If none of them have a pubdate,
this returns the current date/time.
"""
updates = [i['pubdate'] for i in self.items if i['pubdate'] is not None]
if len(updates) > 0:
updates.sort()
return updates[-1]
else:
return datetime.datetime.now()
class Enclosure: class Enclosure:
"Represents an RSS enclosure" "Represents an RSS enclosure"
def __init__(self, url, length, mime_type): def __init__(self, url, length, mime_type):
@ -81,72 +114,136 @@ class RssFeed(SyndicationFeed):
def write(self, outfile, encoding): def write(self, outfile, encoding):
handler = SimplerXMLGenerator(outfile, encoding) handler = SimplerXMLGenerator(outfile, encoding)
handler.startDocument() handler.startDocument()
self.writeRssElement(handler) handler.startElement(u"rss", {u"version": self._version})
self.writeChannelElement(handler)
for item in self.items:
self.writeRssItem(handler, item)
self.endChannelElement(handler)
self.endRssElement(handler)
def writeRssElement(self, handler):
"Adds the <rss> element to handler, taking care of versioning, etc."
raise NotImplementedError
def endRssElement(self, handler):
"Ends the <rss> element."
handler.endElement(u"rss")
def writeChannelElement(self, handler):
handler.startElement(u"channel", {}) handler.startElement(u"channel", {})
handler.addQuickElement(u"title", self.feed_info['title'], {}) handler.addQuickElement(u"title", self.feed['title'])
handler.addQuickElement(u"link", self.feed_info['link'], {}) handler.addQuickElement(u"link", self.feed['link'])
handler.addQuickElement(u"description", self.feed_info['description'], {}) handler.addQuickElement(u"description", self.feed['description'])
if self.feed_info['language'] is not None: if self.feed['language'] is not None:
handler.addQuickElement(u"language", self.feed_info['language'], {}) handler.addQuickElement(u"language", self.feed['language'])
self.write_items(handler)
self.endChannelElement(handler)
handler.endElement(u"rss")
def endChannelElement(self, handler): def endChannelElement(self, handler):
handler.endElement(u"channel") handler.endElement(u"channel")
class RssUserland091Feed(RssFeed): class RssUserland091Feed(RssFeed):
def writeRssElement(self, handler): _version = u"0.91"
handler.startElement(u"rss", {u"version": u"0.91"}) def write_items(self, handler):
for item in self.items:
def writeRssItem(self, handler, item): handler.startElement(u"item", {})
handler.startElement(u"item", {}) handler.addQuickElement(u"title", item['title'])
handler.addQuickElement(u"title", item['title'], {}) handler.addQuickElement(u"link", item['link'])
handler.addQuickElement(u"link", item['link'], {}) if item['description'] is not None:
if item['description'] is not None: handler.addQuickElement(u"description", item['description'])
handler.addQuickElement(u"description", item['description'], {}) handler.endElement(u"item")
handler.endElement(u"item")
class Rss201rev2Feed(RssFeed): class Rss201rev2Feed(RssFeed):
# Spec: http://blogs.law.harvard.edu/tech/rss # Spec: http://blogs.law.harvard.edu/tech/rss
def writeRssElement(self, handler): _version = u"2.0"
handler.startElement(u"rss", {u"version": u"2.0"}) def write_items(self, handler):
for item in self.items:
handler.startElement(u"item", {})
handler.addQuickElement(u"title", item['title'])
handler.addQuickElement(u"link", item['link'])
if item['description'] is not None:
handler.addQuickElement(u"description", item['description'])
def writeRssItem(self, handler, item): # Author information.
handler.startElement(u"item", {}) if item['author_email'] is not None and item['author_name'] is not None:
handler.addQuickElement(u"title", item['title'], {}) handler.addQuickElement(u"author", u"%s (%s)" % \
handler.addQuickElement(u"link", item['link'], {}) (item['author_email'], item['author_name']))
if item['description'] is not None:
handler.addQuickElement(u"description", item['description'], {}) if item['pubdate'] is not None:
if item['author_email'] is not None and item['author_name'] is not None: handler.addQuickElement(u"pubDate", rfc2822_date(item['pubdate']).decode('ascii'))
handler.addQuickElement(u"author", u"%s (%s)" % \ if item['comments'] is not None:
(item['author_email'], item['author_name']), {}) handler.addQuickElement(u"comments", item['comments'])
if item['pubdate'] is not None: if item['unique_id'] is not None:
handler.addQuickElement(u"pubDate", item['pubdate'].strftime('%a, %d %b %Y %H:%M:%S %Z'), {}) handler.addQuickElement(u"guid", item['unique_id'])
if item['comments'] is not None:
handler.addQuickElement(u"comments", item['comments'], {}) # Enclosure.
if item['unique_id'] is not None: if item['enclosure'] is not None:
handler.addQuickElement(u"guid", item['unique_id'], {}) handler.addQuickElement(u"enclosure", '',
if item['enclosure'] is not None: {u"url": item['enclosure'].url, u"length": item['enclosure'].length,
handler.addQuickElement(u"enclosure", '', u"type": item['enclosure'].mime_type})
{u"url": item['enclosure'].url, u"length": item['enclosure'].length,
u"type": item['enclosure'].mime_type}) # Categories.
for cat in item['categories']: for cat in item['categories']:
handler.addQuickElement(u"category", cat, {}) handler.addQuickElement(u"category", cat)
handler.endElement(u"item")
handler.endElement(u"item")
class Atom1Feed(SyndicationFeed):
# Spec: http://atompub.org/2005/07/11/draft-ietf-atompub-format-10.html
ns = u"http://www.w3.org/2005/Atom"
def write(self, outfile, encoding):
handler = SimplerXMLGenerator(outfile, encoding)
handler.startDocument()
if self.feed['language'] is not None:
handler.startElement(u"feed", {u"xmlns": self.ns, u"xml:lang": self.feed['language']})
else:
handler.startElement(u"feed", {u"xmlns": self.ns})
handler.addQuickElement(u"title", self.feed['title'])
handler.addQuickElement(u"link", "", {u"href": self.feed['link']})
handler.addQuickElement(u"id", self.feed['link'])
handler.addQuickElement(u"updated", rfc2822_date(self.latest_post_date()).decode('ascii'))
if self.feed['author_name'] is not None:
handler.startElement(u"author", {})
handler.addQuickElement(u"name", self.feed['author_name'])
if self.feed['author_email'] is not None:
handler.addQuickElement(u"email", self.feed['author_email'])
if self.feed['author_link'] is not None:
handler.addQuickElement(u"uri", self.feed['author_link'])
handler.endElement(u"author")
if self.feed['subtitle'] is not None:
handler.addQuickElement(u"subtitle", self.feed['subtitle'])
for cat in self.feed['categories']:
handler.addQuickElement(u"category", "", {u"term": cat})
self.write_items(handler)
handler.endElement(u"feed")
def write_items(self, handler):
for item in self.items:
handler.startElement(u"entry", {})
handler.addQuickElement(u"title", item['title'])
handler.addQuickElement(u"link", item['link'])
if item['pubdate'] is not None:
handler.addQuickElement(u"updated", rfc2822_date(item['pubdate']).decode('ascii'))
# Author information.
if item['author_name'] is not None:
handler.startElement(u"author", {})
handler.addQuickElement(u"name", item['author_name'])
if item['author_email'] is not None:
handler.addQuickElement(u"email", item['author_email'])
handler.endElement(u"author")
# Unique ID.
if item['unique_id'] is not None:
unique_id = item['unique_id']
else:
unique_id = get_tag_uri(item['link'], item['pubdate'])
handler.addQuickElement(u"id", unique_id)
# Summary.
if item['description'] is not None:
handler.addQuickElement(u"summary", item['description'], {u"type": u"html"})
# Enclosure.
if item['enclosure'] is not None:
handler.addQuickElement(u"link", '',
{u"rel": u"enclosure",
u"href": item['enclosure'].url,
u"length": item['enclosure'].length,
u"type": item['enclosure'].mime_type})
# Categories:
for cat in item['categories']:
handler.addQuickElement(u"category", u"", {u"term": cat})
handler.endElement(u"entry")
# This isolates the decision of what the system default is, so calling code can # This isolates the decision of what the system default is, so calling code can
# do "feedgenerator.DefaultRssFeed" instead of "feedgenerator.Rss201rev2Feed". # do "feedgenerator.DefaultFeed" instead of "feedgenerator.Rss201rev2Feed".
DefaultRssFeed = Rss201rev2Feed DefaultFeed = Rss201rev2Feed

12
django/views/rss/rss.py
View File

@ -1,12 +0,0 @@
from django.core import rss
from django.core.exceptions import Http404
from django.utils.httpwrappers import HttpResponse
def feed(request, slug, param=None):
try:
f = rss.get_registered_feed(slug).get_feed(param)
except (rss.FeedIsNotRegistered, rss.FeedDoesNotExist):
raise Http404
response = HttpResponse(mimetype='application/xml')
f.write(response, 'utf-8')
return response

548
docs/syndication_feeds.txt Normal file
View File

@ -0,0 +1,548 @@
==============================
The syndication feed framework
==============================
Django comes with a high-level syndication-feed-generating framework that makes
creating RSS_ and Atom_ feeds easy.
To create any syndication feed, all you have to do is write a short Python
class. You can create as many feeds as you want.
Django also comes with a lower-level feed-generating API. Use this if you want
to generate feeds outside of a Web context, or in some other lower-level way.
.. _RSS: http://www.whatisrss.com/
.. _Atom: http://www.atomenabled.org/
The high-level framework
========================
Overview
--------
The high-level feed-generating framework is a view that's hooked to ``/feeds/``
by default. Django uses the remainder of the URL (everything after ``/feeds/``)
to determine which feed to output.
To create a feed, just write a ``Feed`` class and point to it in your URLconf_.
.. _URLconf: http://www.djangoproject.com/documentation/url_dispatch/
Initialization
--------------
To activate syndication feeds on your Django site, add this line to your
URLconf_::
(r'^feeds/(?P<url>.*)/$', 'django.contrib.syndication.views.feed', {'feed_dict': feeds}),
This tells Django to use the RSS framework to handle all URLs starting with
``"feeds/"``. (You can change that ``"feeds/"`` prefix to fit your own needs.)
This URLconf line has an extra argument: ``{'feed_dict': feeds}``. Use this
extra argument to pass the syndication framework the feeds that should be
published under that URL.
Specifically, ``feed_dict`` should be a dictionary that maps a feed's slug
(short URL label) to its ``Feed`` class.
You can define the ``feed_dict`` in the URLconf itself. Here's a full example
URLconf::
from django.conf.urls.defaults import *
from myproject.feeds import LatestEntries, LatestEntriesByCategory
feeds = {
'latest': LatestEntries,
'categories': LatestEntriesByCategory,
}
urlpatterns = patterns('',
# ...
(r'^feeds/(?P<url>.*)/$', 'django.contrib.syndication.views.feed',
{'feed_dict': feeds}),
# ...
)
The above example registers two feeds:
* The feed represented by ``LatestEntries`` will live at ``feeds/latest/``.
* The feed represented by ``LatestEntriesByCategory`` will live at
``feeds/categories/``.
Once that's set up, you just need to define the ``Feed`` classes themselves.
.. _URLconf: http://www.djangoproject.com/documentation/url_dispatch/
.. _settings file: http://www.djangoproject.com/documentation/settings/
Feed classes
------------
A ``Feed`` class is a simple Python class that represents a syndication feed.
A feed can be simple (e.g., a "site news" feed, or a basic feed displaying
the latest entries of a blog) or more complex (e.g., a feed displaying all the
blog entries in a particular category, where the category is variable).
``Feed`` classes must subclass ``django.contrib.syndication.feeds.Feed``. They
can live anywhere in your codebase.
A simple example
----------------
This simple example, taken from chicagocrime.org, describes a feed of the
latest five news items::
from django.contrib.syndication.feeds import Feed
from django.models.chicagocrime import newsitems
class SiteNewsFeed(Feed):
title = "Chicagocrime.org site news"
link = "/sitenews/"
description = "Updates on changes and additions to chicagocrime.org."
def items(self):
return newsitems.get_list(order_by=('-pub_date',), limit=5)
Note:
* The class subclasses ``django.contrib.syndication.feeds.Feed``.
* ``title``, ``link`` and ``description`` correspond to the standard
RSS ``<title>``, ``<link>`` and ``<description>`` elements, respectively.
* ``items()`` is, simply, a method that returns a list of objects that
should be included in the feed as ``<item>`` elements. Although this
example returns ``NewsItem`` objects using Django's
`object-relational mapper`_, ``items()`` doesn't have to return model
instances. Although you get a few bits of functionality "for free" by
using Django models, ``items()`` can return any type of object you want.
One thing's left to do. In an RSS feed, each ``<item>`` has a ``<title>``,
``<link>`` and ``<description>``. We need to tell the framework what data to
put into those elements.
* To specify the contents of ``<title>`` and ``<description>``, create
`Django templates`_ called ``feeds/sitenews_title`` and
``feeds/sitenews_description``, where ``sitenews`` is the ``slug``
specified in the URLconf for the given feed. The RSS system renders that
template for each item, passing it two template context variables:
* ``{{ obj }}`` -- The current object (one of whichever objects you
returned in ``items()``).
* ``{{ site }}`` -- A ``django.models.core.sites.Site`` object
representing the current site. This is useful for
``{{ site.domain }}`` or ``{{ site.name }}``.
If you don't create a template for either the title or description, the
framework will use the template ``{{ obj }}`` by default -- that is, the
normal string representation of the object.
* To specify the contents of ``<link>``, you have two options. For each
item in ``items()``, Django first tries executing a
``get_absolute_url()`` method on that object. If that method doesn't
exist, it tries calling a method ``item_link()`` in the ``Feed`` class,
passing it a single parameter, ``item``, which is the object itself.
Both ``get_absolute_url()`` and ``item_link()`` should return the item's
URL as a normal Python string.
.. _object-relational mapper: http://www.djangoproject.com/documentation/db_api/
.. _Django templates: http://www.djangoproject.com/documentation/templates/
A complex example
-----------------
The framework also supports more complex feeds, via parameters.
For example, chicagocrime.org offers an RSS feed of recent crimes for every
police beat in Chicago. It'd be silly to create a separate ``Feed`` class for
each police beat; that would violate the `DRY principle`_ and would couple data
to programming logic. Instead, the RSS framework lets you make generic feeds
that output items based on information in the feed's URL.
On chicagocrime.org, the police-beat feeds are accessible via URLs like this:
* ``/rss/beats/0613/`` -- Returns recent crimes for beat 0613.
* ``/rss/beats/1424/`` -- Returns recent crimes for beat 1424.
The slug here is ``beats``. The syndication framework sees the extra URL bits
after the slug -- ``0613`` and ``1424`` -- and gives you a hook to tell it what
those URL bits mean, and how they should influence which items get published in
the feed.
An example makes this clear. Here's the code for these beat-specific feeds::
class BeatFeed(Feed):
def get_object(self, bits):
# In case of "/rss/beats/0613/foo/bar/baz/", or other such clutter,
# check that bits has only one member.
if len(bits) != 1:
raise ObjectDoesNotExist
return beats.get_object(beat__exact=bits[0])
def title(self, obj):
return "Chicagocrime.org: Crimes for beat %s" % obj.beat
def link(self, obj):
return obj.get_absolute_url()
def description(self, obj):
return "Crimes recently reported in police beat %s" % obj.beat
def items(self, obj):
return crimes.get_list(beat__id__exact=obj.id, order_by=(('-crime_date'),), limit=30)
Here's the basic algorithm the RSS framework follows, given this class and a
request to the URL ``/rss/beats/0613/``:
* The framework gets the URL ``/rss/beats/0613/`` and notices there's
an extra bit of URL after the slug. It splits that remaining string by
the slash character (``"/"``) and calls the ``Feed`` class'
``get_object()`` method, passing it the bits. In this case, bits is
``['0613']``. For a request to ``/rss/beats/0613/foo/bar/``, bits would
be ``['0613', 'foo', 'bar']``.
* ``get_object()`` is responsible for retrieving the given beat, from the
given ``bits``. In this case, it uses the Django database API to retrieve
the beat. Note that ``get_object()`` should raise
``django.core.exceptions.ObjectDoesNotExist`` if given invalid
parameters. There's no ``try``/``except`` around the
``beats.get_object()`` call, because it's not necessary; that function
raises ``BeatDoesNotExist`` on failure, and ``BeatDoesNotExist`` is a
subclass of ``ObjectDoesNotExist``. Raising ``ObjectDoesNotExist`` in
``get_object()`` tells Django to produce a 404 error for that request.
* To generate the feed's ``<title>``, ``<link>`` and ``<description>``,
Django uses the ``title``, ``link`` and ``description`` methods. In the
previous example, they were simple string class attributes, but this
example illustrates that they can be either strings *or* methods. For
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()``.
* Failing that, it tries to call a method with no arguments.
* Failing that, it uses the class attribute.
* 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
finally an ``items`` class attribute (which should be a list).
The ``ExampleFeed`` class below gives full documentation on methods and
attributes of ``Feed`` classes.
.. _DRY principle: http://c2.com/cgi/wiki?DontRepeatYourself
Specifying the type of feed
---------------------------
By default, feeds produced in this framework use RSS 2.0.
To change that, add a ``feed_type`` attribute to your ``Feed`` class, like so::
from django.utils.feedgenerator import Atom1Feed
class MyFeed(Feed):
feed_type = Atom1Feed
Note that you set ``feed_type`` to a class object, not an instance.
Currently available feed types are::
* ``django.utils.feedgenerator.Rss201rev2Feed`` (RSS 2.01. Default.)
* ``django.utils.feedgenerator.RssUserland091Feed`` (RSS 0.91.)
* ``django.utils.feedgenerator.Atom1Feed`` (Atom 1.0.)
Enclosures
----------
To specify enclosures, such as those used in creating podcast feeds, use the
``item_enclosure_url``, ``item_enclosure_length`` and
``item_enclosure_mime_type`` hooks. See the ``ExampleFeed`` class below for
usage examples.
Language
--------
Feeds created by the syndication framework automatically include the
appropriate ``<language>`` tag (RSS 2.0) or ``xml:lang`` attribute (Atom). This
comes directly from your `LANGUAGE_CODE setting`_.
.. _LANGUAGE_CODE setting: http://www.djangoproject.com/documentation/settings/#language-code
Publishing Atom and RSS feeds in tandem
---------------------------------------
Some developers like to make available both Atom *and* RSS versions of their
feeds. That's easy to do with Django: Just create a subclass of your ``feed``
class and set the ``feed_type`` to something different. Then update your
URLconf to add the extra versions.
Here's a full example::
from django.contrib.syndication.feeds import Feed
from django.models.chicagocrime import newsitems
from django.utils.feedgenerator import Atom1Feed
class RssSiteNewsFeed(Feed):
title = "Chicagocrime.org site news"
link = "/sitenews/"
description = "Updates on changes and additions to chicagocrime.org."
def items(self):
return newsitems.get_list(order_by=('-pub_date',), limit=5)
class AtomSiteNewsFeed(RssSiteNewsFeed):
feed_type = Atom1Feed
And the accompanying URLconf::
from django.conf.urls.defaults import *
from myproject.feeds import RssSiteNewsFeed, AtomSiteNewsFeed
feeds = {
'rss': RssSiteNewsFeed,
'atom': AtomSiteNewsFeed,
}
urlpatterns = patterns('',
# ...
(r'^feeds/(?P<url>.*)/$', 'django.contrib.syndication.views.feed',
{'feed_dict': feeds}),
# ...
)
Feed class reference
-------------------
This example illustrates all possible attributes and methods for a ``Feed`` class::
class ExampleFeed(rss.Feed):
# FEED TYPE -- Optional. This should be a class that subclasses
# django.utils.feedgenerator.SyndicationFeed. This designates which
# type of feed this should be: RSS 2.0, Atom 1.0, etc.
# If you don't specify feed_type, your feed will be RSS 2.0.
# This should be a class, not an instance of the class.
feed_type = feedgenerator.Rss201rev2Feed
# TITLE -- One of the following three is required. The framework looks
# for them in this order.
def title(self, obj):
"""
Takes the object returned by get_object() and returns the feed's
title as a normal Python string.
"""
def title(self):
"""
Returns the feed's title as a normal Python string.
"""
title = 'foo' # Hard-coded title.
# LINK -- One of the following three is required. The framework looks
# for them in this order.
def link(self, obj):
"""
Takes the object returned by get_object() and returns the feed's
link as a normal Python string.
"""
def link(self):
"""
Returns the feed's link as a normal Python string.
"""
link = '/foo/bar/' # Hard-coded link.
# DESCRIPTION -- One of the following three is required. The framework
# looks for them in this order.
def description(self, obj):
"""
Takes the object returned by get_object() and returns the feed's
description as a normal Python string.
"""
def description(self):
"""
Returns the feed's description as a normal Python string.
"""
description = 'Foo bar baz.' # Hard-coded description.
# ITEMS -- One of the following three is required. The framework looks
# for them in this order.
def items(self, obj):
"""
Takes the object returned by get_object() and returns a list of
items to publish in this feed.
"""
def items(self):
"""
Returns a list of items to publish in this feed.
"""
items = ('Item 1', 'Item 2') # Hard-coded items.
# GET_OBJECT -- This is required for feeds that publish different data
# for different URL parameters. (See "A complex example" above.)
def get_object(self, bits):
"""
Takes a list of strings gleaned from the URL and returns an object
represented by this feed. Raises
django.core.exceptions.ObjectDoesNotExist on error.
"""
# ITEM LINK -- One of these three is required. The framework looks for
# them in this order.
# First, the framework tries the get_absolute_url() method on each item
# returned by items(). Failing that, it tries these two methods:
def item_link(self, item):
"""
Takes an item, as returned by items(), and returns the item's URL.
"""
def item_link(self):
"""
Returns the URL for every item in the feed.
"""
# ITEM ENCLOSURE URL -- One of these three is required if you're
# publishing enclosures. The framework looks for them in this order.
def item_enclosure_url(self, item):
"""
Takes an item, as returned by items(), and returns the item's
enclosure URL.
"""
def item_enclosure_url(self):
"""
Returns the enclosure URL for every item in the feed.
"""
item_enclosure_url = "/foo/bar.mp3" # Hard-coded enclosure link.
# ITEM ENCLOSURE LENGTH -- One of these three is required if you're
# publishing enclosures. The framework looks for them in this order.
# In each case, the returned value should be either an integer, or a
# string representation of the integer, in bytes.
def item_enclosure_length(self, item):
"""
Takes an item, as returned by items(), and returns the item's
enclosure length.
"""
def item_enclosure_length(self):
"""
Returns the enclosure length for every item in the feed.
"""
item_enclosure_length = 32000 # Hard-coded enclosure length.
# ITEM ENCLOSURE MIME TYPE -- One of these three is required if you're
# publishing enclosures. The framework looks for them in this order.
def item_enclosure_mime_type(self, item):
"""
Takes an item, as returned by items(), and returns the item's
enclosure mime type.
"""
def item_enclosure_mime_type(self):
"""
Returns the enclosure length, in bytes, for every item in the feed.
"""
item_enclosure_mime_type = "audio/mpeg" # Hard-coded enclosure mime-type.
# ITEM PUBDATE -- It's optional to use one of these three. This is a
# hook that specifies how to get the pubdate for a given item.
# In each case, the method/attribute should return a Python
# datetime.datetime object.
def item_pubdate(self, item):
"""
Takes an item, as returned by items(), and returns the item's
pubdate.
"""
def item_pubdate(self):
"""
Returns the pubdate for every item in the feed.
"""
item_pubdate = datetime.datetime(2005, 5, 3) # Hard-coded pubdate.
The low-level framework
=======================
Behind the scenes, the high-level RSS framework uses a lower-level framework
for generating feeds' XML. This framework lives in a single module:
`django/utils/feedgenerator.py`_.
Feel free to use this framework on your own, for lower-level tasks.
The ``feedgenerator`` module contains a base class ``SyndicationFeed`` and
several subclasses:
* ``RssUserland091Feed``
* ``Rss201rev2Feed``
* ``Atom1Feed``
Each of these three classes knows how to render a certain type of feed as XML.
They share this interface::
``__init__(title, link, description, language=None, author_email=None,
author_name=None, author_link=None, subtitle=None, categories=None)``
Initializes the feed with the given metadata, which applies to the entire feed
(i.e., not just to a specific item in the feed).
All parameters, if given, should be Unicode objects, except ``categories``,
which should be a sequence of Unicode objects.
``add_item(title, link, description, author_email=None, author_name=None,
pubdate=None, comments=None, unique_id=None, enclosure=None, categories=())``
Add an item to the feed with the given parameters. All parameters, if given,
should be Unicode objects, except:
* ``pubdate`` should be a Python datetime object.
* ``enclosure`` should be an instance of ``feedgenerator.Enclosure``.
* ``categories`` should be a sequence of Unicode objects.
``write(outfile, encoding)``
Outputs the feed in the given encoding to outfile, which is a file-like object.
``writeString(encoding)``
Returns the feed as a string in the given encoding.
Example usage
-------------
This example creates an Atom 1.0 feed and prints it to standard output::
>>> from django.utils import feedgenerator
>>> f = feedgenerator.Atom1Feed(
... title=u"My Weblog",
... link=u"http://www.example.com/",
... description=u"In which I write about what I ate today.",
... language=u"en"),
>>> f.add_item(title=u"Hot dog today",
... link=u"http://www.example.com/entries/1/",
... description=u"<p>Today I had a Vienna Beef hot dog. It was pink, plump and perfect.</p>")
>>> print f.writeString('utf8')
<?xml version="1.0" encoding="utf8"?>
<feed xmlns="http://www.w3.org/2005/Atom" xml:lang="en"><title>My Weblog</title>
<link href="http://www.example.com/"></link><id>http://www.example.com/</id>
<updated>Sat, 12 Nov 2005 00:28:43 -0000</updated><entry><title>Hot dog today</title>
<link>http://www.example.com/entries/1/</link><id>tag:www.example.com/entries/1/</id>
<summary type="html">&lt;p&gt;Today I had a Vienna Beef hot dog. It was pink, plump and perfect.&lt;/p&gt;</summary>
</entry></feed>
.. _django/utils/feedgenerator.py: http://code.djangoproject.com/browser/django/trunk/django/utils/feedgenerator.py