A simple RSS/Atom reader for Ruby

rss-reader.rb

#!/usr/bin/env ruby
# rss-reader.rb
# Author:   Werner Robitza
# Synopsis: A basic console RSS News Feed reader
# Usage:    rss-reader.rb <url> <granularity>
#           <url> being the URL of the RSS news feed
#           <granularity> is one of: short | medium | full

require 'open-uri'
require 'nokogiri'
require 'pp'
 
def show_usage
  puts "Usage: rss-reader.rb <url> <granularity>"
  puts "<url> being the URL of the RSS news feed"
  puts "<granularity> is one of: short | medium | full"
  exit
end

# -----------------------------------------------------------------------------

show_usage if ARGV.size != 2

# assign parameters
remote_uri, @verbosity = ARGV

# check if right usage of parameters
usage if not ["short", "medium", "full"].include? @verbosity

begin
  @doc = Nokogiri::HTML(open(remote_uri))
  @doc.remove_namespaces!
rescue
  puts "Could not open URI, aborting."
  exit
end

# let's find out if this is RSS or Atom
@type = :atom if @doc.root.xpath("body/feed").size == 1
@type = :rss if @doc.root.xpath("body/rss").size == 1

# print the title
puts @doc.xpath("//channel/title").text if @type == :rss 
puts @doc.xpath("//feed/title").text if @type == :atom

80.times { print "=" } and print "\n"

# print each item  
item_xpath = "//channel/item" if @type == :rss
item_xpath = "//feed/entry" if @type == :atom

@doc.xpath(item_xpath).each do |item|
  puts item.xpath("title").text
  
  if @verbosity == "medium" or @verbosity == "full"
    puts item.xpath("pubdate").text if @type == :rss
    puts item.xpath("published").text if @type == :atom
    puts
    puts item.xpath("description").text.gsub("]]>", "")
    
    if @verbosity == "full" and @type == :rss
      puts
      puts item.xpath("encoded").text.gsub("]]>", "")
    end
    80.times { print "-" } and print "\n"
  end
end