483 lines
16 KiB
Python
483 lines
16 KiB
Python
# Feedformatter
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# Copyright (c) 2008, Luke Maurits <luke@maurits.id.au>
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# Copyright (c) 2020, Laszlo Zeke
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are met:
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#
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# * Redistributions of source code must retain the above copyright notice,
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# this list of conditions and the following disclaimer.
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# * Redistributions in binary form must reproduce the above copyright notice,
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# this list of conditions and the following disclaimer in the documentation
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# and/or other materials provided with the distribution.
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# * The name of the author may not be used to endorse or promote products
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# derived from this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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__version__ = "0.4"
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from io import StringIO
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# This "staircase" of import attempts is ugly. If there's a nicer way to do
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# this, please let me know!
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try:
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import xml.etree.cElementTree as ET
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except ImportError:
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try:
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import xml.etree.ElementTree as ET
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except ImportError:
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try:
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import cElementTree as ET
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except ImportError:
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try:
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from elementtree import ElementTree as ET
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except ImportError:
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raise ImportError("Could not import any form of element tree!")
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try:
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from xml.dom.ext import PrettyPrint
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from xml.dom.ext.reader.Sax import FromXml
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feedformatterCanPrettyPrint = True
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except ImportError:
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feedformatterCanPrettyPrint = False
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from time import time, strftime, localtime, mktime, struct_time, timezone
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# RSS 1.0 Functions ----------
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_rss1_channel_mappings = (
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(("title",), "title"),
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(("link", "url"), "link"),
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(("description", "desc", "summary"), "description")
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)
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_rss1_item_mappings = (
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(("title",), "title"),
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(("link", "url"), "link"),
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(("description", "desc", "summary"), "description")
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)
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# RSS 2.0 Functions ----------
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_rss2_channel_mappings = (
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(("title",), "title"),
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(("link", "url"), "link"),
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(("description", "desc", "summary"), "description"),
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(("pubDate", "pubdate", "date", "published", "updated"), "pubDate", lambda x: _format_datetime("rss2",x)),
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(("category",), "category"),
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(("language",), "language"),
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(("copyright",), "copyright"),
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(("webMaster",), "webmaster"),
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(("image",), "image"),
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(("skipHours",), "skipHours"),
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(("skipDays",), "skipDays"),
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(("ttl",), "ttl")
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)
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_rss2_item_mappings = (
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(("title",), "title"),
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(("link", "url"), "link"),
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(("description", "desc", "summary"), "description"),
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(("guid", "id"), "guid"),
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(("pubDate", "pubdate", "date", "published", "updated"), "pubDate", lambda x: _format_datetime("rss2",x)),
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(("category",), "category"),
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(("author",), "author", lambda x: _rssify_author(x))
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)
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# Atom 1.0 ----------
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_atom_feed_mappings = (
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(("title",), "title"),
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(("link", "url"), "id"),
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(("description", "desc", "summary"), "subtitle"),
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(("pubDate", "pubdate", "date", "published", "updated"), "pubDate", lambda x: _format_datetime("atom",x)),
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(("category",), "category"),
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(("author",), "author", lambda x: _atomise_author(x))
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)
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_atom_item_mappings = (
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(("title",), "title"),
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(("link", "url"), "id"),
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(("link", "url"), "link", lambda x: _atomise_link(x)),
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(("description", "desc", "summary"), "summary"),
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(("pubDate", "pubdate", "date", "published", "updated"), "pubDate", lambda x: _format_datetime("atom",x)),
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(("category",), "category"),
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(("author",), "author", lambda x: _atomise_author(x))
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)
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def _get_tz_offset():
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"""
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Return the current timezone's offset from GMT as a string
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in the format +/-HH:MM, as required by RFC3339.
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"""
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seconds = -1*timezone # Python gets the offset backward! >:(
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minutes = seconds/60
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hours = minutes/60
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minutes = minutes - hours*60
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if seconds < 0:
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return "-%02d:%d" % (hours, minutes)
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else:
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return "+%02d:%d" % (hours, minutes)
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def _convert_datetime(time):
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"""
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Convert time, which may be one of a whole lot of things, into a
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standard 9 part time tuple.
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"""
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if (type(time) is tuple and len(time) ==9) or type(time) is struct_time:
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# Already done!
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return time
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elif type(time) is int or type(time) is float:
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# Assume this is a seconds-since-epoch time
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return localtime(time)
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elif type(time) is str:
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if time.isalnum():
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# String is alphanumeric - a time stamp?
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try:
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return strptime(time, "%a, %d %b %Y %H:%M:%S %Z")
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except ValueError:
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raise Exception("Unrecongised time format!")
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else:
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# Maybe this is a string of an epoch time?
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try:
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return localtime(float(time))
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except ValueError:
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# Guess not.
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raise Exception("Unrecongised time format!")
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else:
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# No idea what this is. Give up!
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raise Exception("Unrecongised time format!")
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def _format_datetime(feed_type, time):
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"""
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Convert some representation of a date and time into a string which can be
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used in a validly formatted feed of type feed_type. Raise an
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Exception if this cannot be done.
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"""
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# First, convert time into a time structure
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time = _convert_datetime(time)
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# Then, convert that to the appropriate string
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if feed_type == "rss2":
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return strftime("%a, %d %b %Y %H:%M:%S UT", time)
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elif feed_type == "atom":
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return strftime("%Y-%m-%dT%H:%M:%S", time) + _get_tz_offset();
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def _atomise_link(link):
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if type(link) is dict:
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return dict
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else:
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return {"href" : link}
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def _atomise_author(author):
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"""
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Convert author from whatever it is to a dictionary representing an
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atom:Person construct.
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"""
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if type(author) is dict:
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return author
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else:
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if author.startswith("http://") or author.startswith("www"):
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# This is clearly a URI
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return {"uri" : author}
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elif "@" in author and "." in author:
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# This is most probably an email address
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return {"email" : author}
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else:
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# Must be a name
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return {"name" : author}
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def _rssify_author(author):
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"""
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Convert author from whatever it is to a plain old email string for
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use in an RSS 2.0 feed.
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"""
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if type(author) is dict:
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try:
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return author["email"]
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except KeyError:
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return None
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else:
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if "@" in author and "." in author:
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# Probably an email address
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return author
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else:
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return None
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def _add_subelems(root_element, mappings, dictionary):
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"""
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Add one subelement to root_element for each key in dictionary
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which is supported by a mapping in mappings
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"""
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for mapping in mappings:
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for key in mapping[0]:
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if key in dictionary:
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if len(mapping) == 2:
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value = dictionary[key]
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elif len(mapping) == 3:
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value = mapping[2](dictionary[key])
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_add_subelem(root_element, mapping[1], value)
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break
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def _add_subelem(root_element, name, value):
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if value is None:
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return
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if type(value) is dict:
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### HORRIBLE HACK!
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if name=="link":
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ET.SubElement(root_element, name, href=value["href"])
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else:
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subElem = ET.SubElement(root_element, name)
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for key in value:
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_add_subelem(subElem, key, value[key])
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else:
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if name == "guid" and not value.startswith("http"):
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el = ET.SubElement(root_element, name)
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el.text = value
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el.attrib["isPermaLink"] = "false"
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else:
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ET.SubElement(root_element, name).text = value
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def _stringify(tree, pretty):
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"""
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Turn an ElementTree into a string, optionally with line breaks and indentation.
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"""
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if pretty and feedformatterCanPrettyPrint:
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string = StringIO()
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doc = FromXml(ET.tostring(tree))
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PrettyPrint(doc,string,indent=" ")
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return string.getvalue()
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else:
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return ET.tostring(tree)
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class Feed:
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### INTERNAL METHODS ------------------------------
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def __init__(self, feed=None, items=None):
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if feed:
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self.feed = feed
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else:
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self.feed = {}
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if items:
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self.items = items
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else:
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self.items = []
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self.entries = self.items
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### RSS 1.0 STUFF ------------------------------
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def validate_rss1(self):
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"""Raise an InvalidFeedException if the feed cannot be validly
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formatted as RSS 1.0."""
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# <channel> must contain "title"
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if "title" not in self.feed:
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raise InvalidFeedException("The channel element of an "
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"RSS 1.0 feed must contain a title subelement")
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# <channel> must contain "link"
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if "link" not in self.feed:
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raise InvalidFeedException("The channel element of an "
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" RSS 1.0 feeds must contain a link subelement")
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# <channel> must contain "description"
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if "description" not in self.feed:
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raise InvalidFeedException("The channel element of an "
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"RSS 1.0 feeds must contain a description subelement")
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# Each <item> must contain "title" and "link"
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for item in self.items:
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if "title" not in item:
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raise InvalidFeedException("Each item element in an RSS 1.0 "
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"feed must contain a title subelement")
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if "link" not in item:
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raise InvalidFeedException("Each item element in an RSS 1.0 "
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"feed must contain a link subelement")
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def format_rss1_string(self, validate=True, pretty=False):
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"""Format the feed as RSS 1.0 and return the result as a string."""
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if validate:
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self.validate_rss1()
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RSS1root = ET.Element( 'rdf:RDF',
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{"xmlns:rdf" : "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
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"xmlns" : "http://purl.org/rss/1.0/"} )
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RSS1channel = ET.SubElement(RSS1root, 'channel',
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{"rdf:about" : self.feed["link"]})
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_add_subelems(RSS1channel, _rss1_channel_mappings, self.feed)
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RSS1contents = ET.SubElement(RSS1channel, 'items')
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RSS1contents_seq = ET.SubElement (RSS1contents, 'rdf:Seq')
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for item in self.items:
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ET.SubElement(RSS1contents_seq, 'rdf:li', resource=item["link"])
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for item in self.items:
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RSS1item = ET.SubElement (RSS1root, 'item',
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{"rdf:about" : item["link"]})
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_add_subelems(RSS1item, _rss1_item_mappings, item)
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return _stringify(RSS1root, pretty=pretty)
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def format_rss1_file(self, filename, validate=True, pretty=False):
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"""Format the feed as RSS 1.0 and save the result to a file."""
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string = self.format_rss1_string(validate, pretty)
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fp = open(filename, "w")
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fp.write(string)
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fp.close()
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### RSS 2.0 STUFF ------------------------------
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def validate_rss2(self):
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"""Raise an InvalidFeedException if the feed cannot be validly
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formatted as RSS 2.0."""
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# <channel> must contain "title"
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if "title" not in self.feed:
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raise InvalidFeedException("The channel element of an "
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"RSS 2.0 feed must contain a title subelement")
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# <channel> must contain "link"
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if "link" not in self.feed:
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raise InvalidFeedException("The channel element of an "
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" RSS 2.0 feeds must contain a link subelement")
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# <channel> must contain "description"
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if "description" not in self.feed:
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raise InvalidFeedException("The channel element of an "
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"RSS 2.0 feeds must contain a description subelement")
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# Each <item> must contain at least "title" OR "description"
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for item in self.items:
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if not ("title" in item or "description" in item):
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raise InvalidFeedException("Each item element in an RSS 2.0 "
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"feed must contain at least a title or description subelement")
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def format_rss2_string(self, validate=True, pretty=False):
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"""Format the feed as RSS 2.0 and return the result as a string."""
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if validate:
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self.validate_rss2()
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RSS2root = ET.Element( 'rss', {'version':'2.0'} )
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RSS2channel = ET.SubElement( RSS2root, 'channel' )
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_add_subelems(RSS2channel, _rss2_channel_mappings, self.feed)
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for item in self.items:
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RSS2item = ET.SubElement ( RSS2channel, 'item' )
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_add_subelems(RSS2item, _rss2_item_mappings, item)
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return _stringify(RSS2root, pretty=pretty)
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def format_rss2_file(self, filename, validate=True, pretty=False):
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"""Format the feed as RSS 2.0 and save the result to a file."""
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string = self.format_rss2_string(validate, pretty)
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fp = open(filename, "w")
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fp.write(string)
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fp.close()
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### ATOM STUFF ------------------------------
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def validate_atom(self):
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"""Raise an InvalidFeedException if the feed cannot be validly
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formatted as Atom 1.0."""
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# Must have at least one "author" element in "feed" OR at least
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# "author" element in each "entry".
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if "author" not in self.feed:
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for entry in self.entries:
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if "author" not in entry:
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raise InvalidFeedException("Atom feeds must have either at "
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"least one author element in the feed element or at least "
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" one author element in each entry element")
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def format_atom_string(self, validate=True, pretty=False):
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"""Format the feed as Atom 1.0 and return the result as a string."""
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if validate:
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self.validate_atom()
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AtomRoot = ET.Element( 'feed', {"xmlns":"http://www.w3.org/2005/Atom"} )
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_add_subelems(AtomRoot, _atom_feed_mappings, self.feed)
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for entry in self.entries:
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AtomItem = ET.SubElement ( AtomRoot, 'entry' )
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_add_subelems(AtomItem, _atom_item_mappings, entry)
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return _stringify(AtomRoot, pretty=pretty)
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def format_atom_file(self, filename, validate=True, pretty=False):
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"""Format the feed as Atom 1.0 and save the result to a file."""
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string = self.format_atom_string(validate, pretty)
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fp = open(filename, "w")
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fp.write(string)
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fp.close()
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class InvalidFeedException(Exception):
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pass
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### FACTORY FUNCTIONS ------------------------------
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def fromUFP(ufp):
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return Feed(ufp["feed"], ufp["items"])
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### MAIN ------------------------------
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def main():
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feed = Feed()
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feed.feed["title"] = "Test Feed"
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feed.feed["link"] = "http://code.google.com/p/feedformatter/"
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feed.feed["author"] = "Luke Maurits"
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feed.feed["description"] = "A simple test feed for the feedformatter project"
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item = {}
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item["title"] = "Test item"
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item["link"] = "http://www.python.org"
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item["description"] = "Python programming language"
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item["guid"] = "1234567890"
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feed.items.append(item)
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print("---- RSS 1.0 ----")
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print(feed.format_rss1_string(pretty=True))
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print("---- RSS 2.0 ----")
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print(feed.format_rss2_string(pretty=True))
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print("---- Atom 1.0 ----")
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print(feed.format_atom_string(pretty=True))
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if __name__ == "__main__":
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main()
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