392 lines
15 KiB
Python
392 lines
15 KiB
Python
"""
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Syndication feed generation library -- used for generating RSS, etc.
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Sample usage:
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>>> from django.utils import feedgenerator
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>>> feed = feedgenerator.Rss201rev2Feed(
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... title="Poynter E-Media Tidbits",
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... link="http://www.poynter.org/column.asp?id=31",
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... description="A group blog by the sharpest minds in online media/journalism/publishing.",
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... language="en",
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... )
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>>> feed.add_item(
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... title="Hello",
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... link="http://www.holovaty.com/test/",
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... description="Testing."
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... )
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>>> with open('test.rss', 'w') as fp:
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... feed.write(fp, 'utf-8')
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For definitions of the different versions of RSS, see:
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https://web.archive.org/web/20110718035220/http://diveintomark.org/archives/2004/02/04/incompatible-rss
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"""
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import datetime
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import email
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from io import StringIO
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from urllib.parse import urlparse
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from django.utils.encoding import iri_to_uri
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from django.utils.timezone import utc
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from django.utils.xmlutils import SimplerXMLGenerator
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def rfc2822_date(date):
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if not isinstance(date, datetime.datetime):
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date = datetime.datetime.combine(date, datetime.time())
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return email.utils.format_datetime(date)
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def rfc3339_date(date):
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if not isinstance(date, datetime.datetime):
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date = datetime.datetime.combine(date, datetime.time())
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return date.isoformat() + ('Z' if date.utcoffset() is None else '')
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def get_tag_uri(url, date):
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"""
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Create a TagURI.
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See https://web.archive.org/web/20110514113830/http://diveintomark.org/archives/2004/05/28/howto-atom-id
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"""
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bits = urlparse(url)
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d = ''
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if date is not None:
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d = ',%s' % date.strftime('%Y-%m-%d')
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return 'tag:%s%s:%s/%s' % (bits.hostname, d, bits.path, bits.fragment)
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class SyndicationFeed:
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"Base class for all syndication feeds. Subclasses should provide write()"
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def __init__(self, title, link, description, language=None, author_email=None,
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author_name=None, author_link=None, subtitle=None, categories=None,
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feed_url=None, feed_copyright=None, feed_guid=None, ttl=None, **kwargs):
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def to_str(s):
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return str(s) if s is not None else s
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categories = categories and [str(c) for c in categories]
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self.feed = {
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'title': to_str(title),
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'link': iri_to_uri(link),
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'description': to_str(description),
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'language': to_str(language),
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'author_email': to_str(author_email),
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'author_name': to_str(author_name),
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'author_link': iri_to_uri(author_link),
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'subtitle': to_str(subtitle),
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'categories': categories or (),
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'feed_url': iri_to_uri(feed_url),
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'feed_copyright': to_str(feed_copyright),
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'id': feed_guid or link,
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'ttl': to_str(ttl),
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**kwargs,
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}
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self.items = []
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def add_item(self, title, link, description, author_email=None,
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author_name=None, author_link=None, pubdate=None, comments=None,
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unique_id=None, unique_id_is_permalink=None, categories=(),
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item_copyright=None, ttl=None, updateddate=None, enclosures=None, **kwargs):
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"""
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Add an item to the feed. All args are expected to be strings except
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pubdate and updateddate, which are datetime.datetime objects, and
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enclosures, which is an iterable of instances of the Enclosure class.
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"""
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def to_str(s):
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return str(s) if s is not None else s
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categories = categories and [to_str(c) for c in categories]
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self.items.append({
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'title': to_str(title),
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'link': iri_to_uri(link),
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'description': to_str(description),
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'author_email': to_str(author_email),
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'author_name': to_str(author_name),
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'author_link': iri_to_uri(author_link),
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'pubdate': pubdate,
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'updateddate': updateddate,
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'comments': to_str(comments),
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'unique_id': to_str(unique_id),
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'unique_id_is_permalink': unique_id_is_permalink,
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'enclosures': enclosures or (),
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'categories': categories or (),
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'item_copyright': to_str(item_copyright),
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'ttl': to_str(ttl),
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**kwargs,
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})
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def num_items(self):
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return len(self.items)
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def root_attributes(self):
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"""
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Return extra attributes to place on the root (i.e. feed/channel) element.
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Called from write().
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"""
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return {}
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def add_root_elements(self, handler):
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"""
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Add elements in the root (i.e. feed/channel) element. Called
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from write().
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"""
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pass
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def item_attributes(self, item):
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"""
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Return extra attributes to place on each item (i.e. item/entry) element.
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"""
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return {}
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def add_item_elements(self, handler, item):
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"""
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Add elements on each item (i.e. item/entry) element.
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"""
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pass
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def write(self, outfile, encoding):
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"""
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Output the feed in the given encoding to outfile, which is a file-like
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object. Subclasses should override this.
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"""
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raise NotImplementedError('subclasses of SyndicationFeed must provide a write() method')
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def writeString(self, encoding):
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"""
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Return the feed in the given encoding as a string.
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"""
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s = StringIO()
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self.write(s, encoding)
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return s.getvalue()
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def latest_post_date(self):
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"""
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Return the latest item's pubdate or updateddate. If no items
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have either of these attributes this return the current UTC date/time.
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"""
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latest_date = None
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date_keys = ('updateddate', 'pubdate')
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for item in self.items:
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for date_key in date_keys:
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item_date = item.get(date_key)
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if item_date:
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if latest_date is None or item_date > latest_date:
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latest_date = item_date
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return latest_date or datetime.datetime.now(tz=utc)
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class Enclosure:
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"""An RSS enclosure"""
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def __init__(self, url, length, mime_type):
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"All args are expected to be strings"
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self.length, self.mime_type = length, mime_type
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self.url = iri_to_uri(url)
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class RssFeed(SyndicationFeed):
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content_type = 'application/rss+xml; charset=utf-8'
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def write(self, outfile, encoding):
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handler = SimplerXMLGenerator(outfile, encoding, short_empty_elements=True)
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handler.startDocument()
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handler.startElement("rss", self.rss_attributes())
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handler.startElement("channel", self.root_attributes())
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self.add_root_elements(handler)
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self.write_items(handler)
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self.endChannelElement(handler)
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handler.endElement("rss")
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def rss_attributes(self):
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return {
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'version': self._version,
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'xmlns:atom': 'http://www.w3.org/2005/Atom',
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}
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def write_items(self, handler):
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for item in self.items:
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handler.startElement('item', self.item_attributes(item))
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self.add_item_elements(handler, item)
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handler.endElement("item")
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def add_root_elements(self, handler):
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handler.addQuickElement("title", self.feed['title'])
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handler.addQuickElement("link", self.feed['link'])
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handler.addQuickElement("description", self.feed['description'])
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if self.feed['feed_url'] is not None:
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handler.addQuickElement("atom:link", None, {"rel": "self", "href": self.feed['feed_url']})
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if self.feed['language'] is not None:
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handler.addQuickElement("language", self.feed['language'])
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for cat in self.feed['categories']:
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handler.addQuickElement("category", cat)
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if self.feed['feed_copyright'] is not None:
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handler.addQuickElement("copyright", self.feed['feed_copyright'])
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handler.addQuickElement("lastBuildDate", rfc2822_date(self.latest_post_date()))
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if self.feed['ttl'] is not None:
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handler.addQuickElement("ttl", self.feed['ttl'])
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def endChannelElement(self, handler):
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handler.endElement("channel")
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class RssUserland091Feed(RssFeed):
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_version = "0.91"
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def add_item_elements(self, handler, item):
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handler.addQuickElement("title", item['title'])
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handler.addQuickElement("link", item['link'])
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if item['description'] is not None:
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handler.addQuickElement("description", item['description'])
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class Rss201rev2Feed(RssFeed):
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# Spec: https://cyber.harvard.edu/rss/rss.html
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_version = "2.0"
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def add_item_elements(self, handler, item):
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handler.addQuickElement("title", item['title'])
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handler.addQuickElement("link", item['link'])
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if item['description'] is not None:
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handler.addQuickElement("description", item['description'])
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# Author information.
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if item["author_name"] and item["author_email"]:
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handler.addQuickElement("author", "%s (%s)" % (item['author_email'], item['author_name']))
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elif item["author_email"]:
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handler.addQuickElement("author", item["author_email"])
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elif item["author_name"]:
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handler.addQuickElement(
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"dc:creator", item["author_name"], {"xmlns:dc": "http://purl.org/dc/elements/1.1/"}
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)
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if item['pubdate'] is not None:
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handler.addQuickElement("pubDate", rfc2822_date(item['pubdate']))
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if item['comments'] is not None:
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handler.addQuickElement("comments", item['comments'])
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if item['unique_id'] is not None:
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guid_attrs = {}
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if isinstance(item.get('unique_id_is_permalink'), bool):
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guid_attrs['isPermaLink'] = str(item['unique_id_is_permalink']).lower()
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handler.addQuickElement("guid", item['unique_id'], guid_attrs)
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if item['ttl'] is not None:
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handler.addQuickElement("ttl", item['ttl'])
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# Enclosure.
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if item['enclosures']:
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enclosures = list(item['enclosures'])
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if len(enclosures) > 1:
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raise ValueError(
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"RSS feed items may only have one enclosure, see "
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"http://www.rssboard.org/rss-profile#element-channel-item-enclosure"
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)
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enclosure = enclosures[0]
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handler.addQuickElement('enclosure', '', {
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'url': enclosure.url,
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'length': enclosure.length,
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'type': enclosure.mime_type,
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})
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# Categories.
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for cat in item['categories']:
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handler.addQuickElement("category", cat)
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class Atom1Feed(SyndicationFeed):
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# Spec: https://tools.ietf.org/html/rfc4287
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content_type = 'application/atom+xml; charset=utf-8'
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ns = "http://www.w3.org/2005/Atom"
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def write(self, outfile, encoding):
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handler = SimplerXMLGenerator(outfile, encoding, short_empty_elements=True)
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handler.startDocument()
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handler.startElement('feed', self.root_attributes())
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self.add_root_elements(handler)
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self.write_items(handler)
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handler.endElement("feed")
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def root_attributes(self):
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if self.feed['language'] is not None:
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return {"xmlns": self.ns, "xml:lang": self.feed['language']}
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else:
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return {"xmlns": self.ns}
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def add_root_elements(self, handler):
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handler.addQuickElement("title", self.feed['title'])
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handler.addQuickElement("link", "", {"rel": "alternate", "href": self.feed['link']})
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if self.feed['feed_url'] is not None:
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handler.addQuickElement("link", "", {"rel": "self", "href": self.feed['feed_url']})
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handler.addQuickElement("id", self.feed['id'])
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handler.addQuickElement("updated", rfc3339_date(self.latest_post_date()))
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if self.feed['author_name'] is not None:
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handler.startElement("author", {})
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handler.addQuickElement("name", self.feed['author_name'])
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if self.feed['author_email'] is not None:
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handler.addQuickElement("email", self.feed['author_email'])
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if self.feed['author_link'] is not None:
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handler.addQuickElement("uri", self.feed['author_link'])
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handler.endElement("author")
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if self.feed['subtitle'] is not None:
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handler.addQuickElement("subtitle", self.feed['subtitle'])
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for cat in self.feed['categories']:
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handler.addQuickElement("category", "", {"term": cat})
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if self.feed['feed_copyright'] is not None:
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handler.addQuickElement("rights", self.feed['feed_copyright'])
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def write_items(self, handler):
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for item in self.items:
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handler.startElement("entry", self.item_attributes(item))
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self.add_item_elements(handler, item)
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handler.endElement("entry")
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def add_item_elements(self, handler, item):
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handler.addQuickElement("title", item['title'])
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handler.addQuickElement("link", "", {"href": item['link'], "rel": "alternate"})
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if item['pubdate'] is not None:
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handler.addQuickElement('published', rfc3339_date(item['pubdate']))
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if item['updateddate'] is not None:
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handler.addQuickElement('updated', rfc3339_date(item['updateddate']))
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# Author information.
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if item['author_name'] is not None:
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handler.startElement("author", {})
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handler.addQuickElement("name", item['author_name'])
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if item['author_email'] is not None:
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handler.addQuickElement("email", item['author_email'])
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if item['author_link'] is not None:
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handler.addQuickElement("uri", item['author_link'])
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handler.endElement("author")
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# Unique ID.
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if item['unique_id'] is not None:
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unique_id = item['unique_id']
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else:
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unique_id = get_tag_uri(item['link'], item['pubdate'])
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handler.addQuickElement("id", unique_id)
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# Summary.
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if item['description'] is not None:
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handler.addQuickElement("summary", item['description'], {"type": "html"})
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# Enclosures.
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for enclosure in item['enclosures']:
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handler.addQuickElement('link', '', {
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'rel': 'enclosure',
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'href': enclosure.url,
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'length': enclosure.length,
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'type': enclosure.mime_type,
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})
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# Categories.
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for cat in item['categories']:
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handler.addQuickElement("category", "", {"term": cat})
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# Rights.
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if item['item_copyright'] is not None:
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handler.addQuickElement("rights", item['item_copyright'])
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# This isolates the decision of what the system default is, so calling code can
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# do "feedgenerator.DefaultFeed" instead of "feedgenerator.Rss201rev2Feed".
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DefaultFeed = Rss201rev2Feed
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