#!/usr/bin/perl -w

# ETag-aware wget
# Uses wget to more politely retrieve HTTP based information
# DJ Adams
# Version 0+1b

# wget --header='If-None-Match: "3ea6d375;3e2eee38"' http://www.w3.org/

# Changes
# 0+1b 2003-02-03 dja added User-Agent string to wget call
# 0+1 original version

use strict;
my $cachedir = '/tmp/etagcache'; # change this if you want
my $etagfile = "$cachedir/".unpack("H*", $ARGV[0]); 
my $etag = `cat $etagfile 2>/dev/null`;
$etag =~ s/\\"/"/g;
$etag =~ s/^ETag: (.*?)\n$/$1/ and $etag = qq[--header='If-None-Match: $etag'];

my $com="wget -U 'blagg/0+4i+ (wget.pl/0+1b)' --timeout=60 -s --quiet $etag -O - $ARGV[0]";
print "Running: $com";

my ($headers, $body) = split(/\n\n/, `wget -U 'blagg/0+4i+ (wget.pl/0+1b)' --timeout=60 -s --quiet $etag -O - $ARGV[0]`, 2);
print "Got headers: $headers\n\n";
if (defined $body) {
  ($etag) = $headers =~ /^(ETag:.*?)$/m;
  print "Return value etag: $etag";
  defined $etag and $etag =~ s/\"/\\\"/g, `echo '$etag' > $etagfile`;
  print "\n==========\n";
  print $body;
}
else {
  print "Cached.";
}