in reply to Re^3: How to get web creation date from webserver?
in thread How to get web creation date from webserver?

You could fetch the page with LWP, calculate & store an MD5 checksum, then simply compare the current checksum with the last one.

Code hastily snipped and sanitised :) 

use Digest::MD5 qw/md5_hex/;
sub web_MD5 {
    # get MD5 sum of an url
    my $url = shift;
    my $ua = LWP::UserAgent->new(env_proxy => 1,
                 keep_alive => 1,
                 timeout => 30);
    my $response = $ua->get($url);
    unless ($response->is_success) {
      # failed to fetch
      print "Error fetching ", $url, " ",    
      $response->status_line;
    }
    warn "Error while getting ", $response->request->uri,
      " -- ", $response->status_line, "\nAborting";
    unless $response->is_success;
    my $doc = $response->content();
    my $md5 = md5_hex($doc);
    undef $ua;
    return $md5;
}

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Re^5: How to get web creation date from webserver?
by holli (Abbot) on Aug 24, 2005 at 15:54 UTC
    A few suggestions:

    Once you have fetched the page you could simply and blindly write it over the old version to the disk. That would be cheaper than calculating a checksum, esp. because you have to download the page twice (your function does not return the fetched data). So i would at least alter your code. 
    return ($md5, \$response);

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    Also, you do not return (but warn) when when the fetch fails. I didn't check what happens when you md5_hexing an undef value and what the code returns. It should return undef to indicate the failure to the caller. So, even if your code works, it would be simply clearer when you explicitly return undef when the fetch fails. 
    unless ($response->is_success)
{
  warn "Error while getting ", $response->request->uri,
       " -- ", $response->status_line, "\nAborting";
  return;
}

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    holli, /regexed monk/
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