PyRSS2Gen-1.0

       A Python library for generating RSS 2.0 feeds.

Requires Python 2.3.  (Uses the datetime module for timestamps.)

To install:

  % python setup.py install

This uses the standard Python installer.  For more details, read

    http://docs.python.org/inst/inst.html

(And there's only one file, so you could just copy it wherever you
need it.)

NOTE: PyRSS2Gen 1.0 is a maintainence release for version 0.1 released
in September 2003.


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I've finally decided to catch up with 1999 and play around a bit with
RSS.  I looked around, and while there are many ways to read RSS there
are remarkably few which write them.  I could use a DOM or other
construct, but I want the code to feel like Python.  There are more
Pythonic APIs I might use, like the effbot's ElementTree, but I also
wanted integers, dates, and lists to be real integers, dates, and
lists.  (And I want bug-eyed monsters from Alpha Centauri to be *real*
bug-eyed monsters from Alpha Centauri - is that too much I ask you?)

The RSS generators I found were built around print statements.
Workable, but they almost invariably left out proper HTML escaping the
sort which leads to Mark Pilgrim's to write feed_parser, to make sense
of documents which are neither XML nor HTML.  Annoying, but sadly all
too common.

So I messed around a bit with the spec from
 http://blogs.law.harvard.edu/tech/rss

The result looks like this:

import datetime
import PyRSS2Gen

rss = PyRSS2Gen.RSS2(
    title = "Andrew's PyRSS2Gen feed",
    link = "http://www.dalkescientific.com/Python/PyRSS2Gen.html",
    description = "The latest news about PyRSS2Gen, a "
                  "Python library for generating RSS2 feeds",

    lastBuildDate = datetime.datetime.now(),

    items = [
       PyRSS2Gen.RSSItem(
         title = "PyRSS2Gen-0.0 released",
         link = "http://www.dalkescientific.com/news/030906-PyRSS2Gen.html",
         description = "Dalke Scientific today announced PyRSS2Gen-0.0, "
                       "a library for generating RSS feeds for Python.  ",
         guid = PyRSS2Gen.Guid("http://www.dalkescientific.com/news/"
                          "030906-PyRSS2Gen.html"),
         pubDate = datetime.datetime(2003, 9, 6, 21, 31)),
       PyRSS2Gen.RSSItem(
         title = "Thoughts on RSS feeds for bioinformatics",
         link = "http://www.dalkescientific.com/writings/diary/"
                "archive/2003/09/06/RSS.html",
         description = "One of the reasons I wrote PyRSS2Gen was to "
                       "experiment with RSS for data collection in "
                       "bioinformatics.  Last year I came across...",
         guid = PyRSS2Gen.Guid("http://www.dalkescientific.com/writings/"
                               "diary/archive/2003/09/06/RSS.html"),
         pubDate = datetime.datetime(2003, 9, 6, 21, 49)),
    ])

rss.write_xml(open("pyrss2gen.xml", "w"))


The output does not contain newlines, so if you want to read it,
you'll need to use your favorite XML tools to reformat it.

RSS is not a fixed format.  People are free to add various metadata,
like Dublin Core elements.

The RSS objects are converted to XML using the 'publish' method, which
takes a SAX2 ContentHandler.  If you want different output, implement
your own 'publish'.  The "simple" data types which takes a string,
int, or date, can be replaced with a publishable object, so you can
add metadata to, say, the "description" field.  To support new
elements for RSS and RSSItem, derive from them and use the
'publish_extensions" hook.  To add your own attributes (needed for
namespace declarations), redefine 'element_attrs' or 'rss_attrs' in
your subclass.

To use a different encoding, create your own ContentHandler instead of
using the helper methods 'to_xml' and 'write_xml.'  You'll need to
make sure the 'characters' method in the handler does the appropriate
translation.

The "categories" list is somewhat special.  It needs to be a list and
doesn't have a publish method.  That's because the RSS spec doesnt'
have an explicit concept for the set of categories -- an RSS2 channel
can have 0 or more 'category' elements, but doesn't have a "list of
categories" -- my "categories" attribute is an API fiction.

BUGS:

Several people have used this package since its first release in
September of 2003 and reported a couple of bugs.  All those are fixed.
There are no known bugs.

The name PyRSS2Gen is a mouthful.  It didn't think it was useful to
come up with a cute name.  You might consider having

   import PyRSS2Gen as RSS2

in any code which uses this module.  I'm not changing the name because
anyone who reads "RSS2" will likely think it's a parser and not a
generator.  Plus, the current name is very easy to find via a web
search.

LICENSE:

This is copyright (c) by Dalke Scientific Software, LLC
and released under the BSD license.  See the file LICENSE
in the distribution or 
  http://www.opensource.org/licenses/bsd-license.php
for details.

CHANGES for 1.0:
  - many people (Richard Chamberlain, Daniel Hsu, Leonart Richardson
  and Daniel Holth) pointed out that Guid sets "isPermaLink" (with a
  "L" not "l").  Fixed, and changed it so the isPermaLink RSS attribute
  is always either "true" or "false" instead of assuming empty means false.

  - Added patches from Erik de Jonge and MATSUNO Tokuhiro to set the
  output encoding.

  - Implemented a suggestion by Daniel Hoth to convert the enclosure
  length to a string.

CHANGES for 0.1.1:
  - retrospectively renamed "0.0" to "0.1"
  - fixed bug in Image height.  Patch thanks to Edward Dale.