This post originated from an RSS feed registered with Python Buzz by Ng Pheng Siong. Original Post: From Snownews To BottomFeeder Feed Title: (render-blog Ng Pheng Siong) Feed URL: http://sandbox.rulemaker.net/ngps/rdf10_xml Feed Description: Just another this here thing blog. Latest Python Buzz Posts Latest Python Buzz Posts by Ng Pheng Siong Latest Posts From (render-blog Ng Pheng Siong)

I got the itch to try BottomFeeder out seriously. I've been using Snownews; "wc -l" reports that my Snownews subscription list is 229-strong. Certainly I'm not about to resubscribe to each of these by hand in BottomFeeder.

BottomFeeder supports importing and exporting feeds. Supposedly it imports from the following file types: BTF, RSS, XML, ini and text. I have no idea what these formats are, so I took the simplest approach: subscribe to a single feed, export it and examine the exported file visually... Ah, the export file is in something called OPML - Outline Processor Markup Language.

Next, googled "snownews opml" and found the following:

• snow2opml
• opml2snow

Both are Perl programs. The first uses HTML::Entities and the second XML::LibXML and Data:Dumper. It's been a long time since I last installed anything via CPAN and I didn't feel like trying again right then.

Went back to inspecting the exported OPML file... the XML looked simple enough... there, cooked up a chunk of Python code to generate each outline item:

import sys

TEMPLATE = """\
<outline description="..." htmlUrl="" language="en" text="" xmlUrl="%s"/>
"""

while 1:
    line = sys.stdin.readline()
    if not line: break
    print TEMPLATE % line

There were two more steps before the generated output was usable by BottomFeeder:

» Snownews' 'urls' file stores one feed per line; each line contains the feed's URL and a bunch of meta-information, separated by "|". Cooked up a quickie awk script to print just the URL; these URLs are the input to the above Python code

» After running the Python code, filled in the OPML template information by hand.

(Incorporating these two steps into the Python code is left as an exercise for the reader. ;-)

And that was it. BottomFeeder imported the feed successfully and is presently crunching thru the feeds doing whatever it is supposed to be doing...