README for XML-RSS-TimingBot

Time-stamp: "2004-04-24 01:22:57 ADT"

NAME

XML::RSS::TimingBot -- for efficiently fetching RSS feeds

SYNOPSIS

      use XML::RSS::TimingBot;
      $browser = XML::RSS::TimingBot->new;

      my $response = $browser->get(
        'http://interglacial.com/rss/cairo_times.rss'
         # or whatever feed
      );

      ... And process $response just as if it came from
         a plain old LWP::UserAgent object, for example: ...
  
      if($response->code == 200) {  # 200 = "okay, here it is"
        ...process it...
      } elsif($response->code == 304) { # 304 = "Not Changed"
        # do nothing
      } else {
        print "Hm, couldn't access it: ", $response->status_line, "\n";
      }
  
      $browser->commit;   # Save our history.  Don't forget!!

DESCRIPTION

If you use LWP::UserAgent for fetching RSS/RDF feeds, use XML::RSS::TimingBot instead! XML::RSS::TimingBot has the same interface, but knows when to more efficiently request the data.

DETAILED DESCRIPTION
XML::RSS::TimingBot is for requesting RSS feeds only as often as needed. This class does this in two ways:

• When you request a feed the first time, this class remembers what Last-Modified and ETag headers it has; that the next time you request that feed, this class can specify that the feed's server should return data only if that feed has changed since last time, or has a different ETag value. If the feed has changed, you'll get the HTTP response back with full content and with a normal "200" status code. If the feed hasn't changed, you'll get a contentless "304" response (meaning "I'm not giving you any content, because it hasn't changed").
• When you request a feed, this class remembers any data that might be in the RSS that says how often this feed updates. See XML::RSS::Timing for the full story; but as a common example if there's a "<ttl>180</ttl>" in the feed, that means that the feed will rebuild only once every three hours (180 minutes). When this class sees that in the received RSS data, it remembers this so that if you go to get the feed more often than that, it will stop you and give a "304" (Not Modified) error response.

[continued in the documentation for this module, which you can read with perldoc]

INSTALLATION

You install this Perl module, as you would install any Perl module library, by running these commands:

perl Makefile.PL
make
make test
make install

If you want to install a private copy of this module in your home directory, then you should try to produce the initial Makefile with something like this command:

perl Makefile.PL PREFIX=~/perl

See "perldoc perlmodinstall" for more information and advice.

This module doesn't depend on XML::RSS, nor in fact have any particular relationship with it.