Exercise-1-1

Exercise-1-1

# Exercise:  Take this file and add some RSS parsing to it.
# Perhaps revealing which items are new since the last time you checked.

require 'open-uri'

url = 'http://scoops.totallyrule.com/xml/rss/feed.xml' # pick an rss feed to track
lastfile = 'lastmod.log' # file to save/retrieve the time we checked

# let's check to see when we last hit this feed
lastcheck = File.open(lastfile, 'r').read.chomp

# now convert the time to a Time object with the correct net standard
lastcheck = Time.parse(lastcheck).rfc2822

begin

  # we're passing in a simple hash to apply our header
  # If-Modified-Since will compare our time to the modified time of the file
  # on the server and if it's newer than lastcheck it will give us the feed
  # otherwise we get nothing and the rescue part kicks in

  open(url, { 'If-Modified-Since' => lastcheck }) do |feed|
    puts "The feed has changed.\n"

    # Try something more interesting here with the rss module
    # Tutorial: http://www.cozmixng.org/~rwiki/?cmd=view;name=RSS+Parser%3A%3ATutorial.en
  end

rescue OpenURI::HTTPError # the exception open-uri throws on http errors
  puts "No file available or file has not changed.\n"
ensure

  # save the time of this check
  # this part happens good or bad

  File.open(lastfile, 'w') do |f|
    f.write(Time.now.to_s + "\n")
  end
end

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