From: Jonathan Groll <lists@...>
Date: 2009-06-26T23:52:37+09:00
Subject: Two ways to generate RSS - rss/maker and rss/2.0 - which is better?

 From some fiddling I've found that there are two ways to generate RSS
using the rubyRSS libraries shipped with ruby 1.8.7. 

Neither method seems ideal for generating RSS 2.0 (the RSS XML
produced seems to be missing tags/attributes that I would like in both
cases). Is there something that I'm missing and is there a preferred
method?

In particular, I would like to use the 'guid' attribute with rss/maker
but it seems to be unsupported? Surely there are some feed readers who
depend on this for determining if an item is unique? It does seem the
'guid' is a part of the RSS 2.0 standard.

However, if I were to use the rss/2.0 method, I could specify the
guid, but would lose the <dc:date> attribute and all of the xmlns
definitions at the top. Also with rss/2.0 I couldn't work out how to
do a reverse sort of items (is this even needed though).

Any comments?

Method 1: rss/maker, simplest example:

#!/usr/bin/env ruby
require 'rss/maker'

if __FILE__ == $0
   content = RSS::Maker.make('2.0') do |m|
     m.channel.title = "title"
     m.channel.about = "about" # <<<=seems to not be used
     m.channel.link  = "www.example.com"
     m.channel.description = "desc"
     m.items.do_sort = true # <<<= sort items by date

     2.times do |n|
       i = m.items.new_item
       i.title = "title"
       i.link =  "www.example.com/" + n.to_s
       # i.guid =    <<<=Not supported
       i.description = "Main body"
       i.date = Time.now
     end
   end

   puts content.to_s
end

Outputs:
<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0"
   xmlns:content="http://purl.org/rss/1.0/modules/content/"
   xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd"
   xmlns:dc="http://purl.org/dc/elements/1.1/"
   xmlns:trackback="http://madskills.com/public/xml/rss/module/trackback/">
   <channel>
     <title>title</title>
     <link>www.example.com</link>
     <description>desc</description>
     <item>
       <title>title</title>
       <link>www.example.com/1</link>
       <description>Main body</description>
       <pubDate>Fri, 26 Jun 2009 16:35:31 +0200</pubDate>
       <dc:date>2009-06-26T16:35:31.598452+02:00</dc:date>
     </item>
     <item>
       <title>title</title>
       <link>www.example.com/0</link>
       <description>Main body</description>
       <pubDate>Fri, 26 Jun 2009 16:35:31 +0200</pubDate>
       <dc:date>2009-06-26T16:35:31.592903+02:00</dc:date>
     </item>
   </channel>
</rss>

Method 2: rss/2.0, simplest example:

#!/usr/bin/env ruby

require 'rss/2.0'
if __FILE__ == $0

   content = RSS::Rss.new('2.0')
   channel = RSS::Rss::Channel.new

   channel.title = "title"
   channel.link  = "www.example.com"
   channel.description = "desc"
   #channel.item.do_sort = true "<<<=Cannot sort

   2.times do |n|
     i =  RSS::Rss::Channel::Item.new
     i.title = "title"
     i.link =  "www.example.com/" + n.to_s
     i.guid = RSS::Rss::Channel::Item::Guid.new
     i.guid.content = n.to_s
     i.guid.isPermaLink = true
     i.description = "Main body"
     i.date = Time.now
     channel.items << i
   end

   content.channel = channel
   puts content.to_s

end

Outputs:
<?xml version="1.0"?>
<rss version="2.0">
   <channel>
     <title>title</title>
     <link>www.example.com</link>
     <description>desc</description>
     <item>
       <title>title</title>
       <link>www.example.com/0</link>
       <description>Main body</description>
       <pubDate>Fri, 26 Jun 2009 16:39:37 +0200</pubDate>
       <guid isPermaLink="true">0</guid>
     </item>
     <item>
       <title>title</title>
       <link>www.example.com/1</link>
       <description>Main body</description>
       <pubDate>Fri, 26 Jun 2009 16:39:37 +0200</pubDate>
       <guid isPermaLink="true">1</guid>
     </item>
   </channel>
</rss>

Regards,
Jonathan Groll.