#!/usr/bin/perl


# EasyRSS
# Quickie RSS feed from TSV
# Stephen Downes - February 17, 2011

# Set Variables to Taste

my $TSVfile = "easyrss_file.tsv";
my $feed_title = "Demo Feed";
my $feed_url = "http://www.downes.ca/testfeed.htm";
my $feed_description = "This is a demo feed.";
my $language = "en-us";
my $managingEditor = "stephen@downes.ca (Stephen Downes)";
my $webMaster = "stephen@downes.ca (Stephen Downes)";



# Print Header
if ($ENV{'user_agent'} =~ /Mozilla/) { print "Content-Type: text/xml\n\n"; }
else { print "Content-type: application/rss+xml\n\n"; }


# Print Feed Channel Info
my $pubdate = &rfc822_date(time); 
print qq|<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0">
   <channel>
      <title>$feed_title</title>
      <link>$feed_url</link>
      <description>$feed_description</description>
      <pubDate>$pubdate</pubDate>
      <lastBuildDate>$pubdate</lastBuildDate>
      <language>$language</language>
      <docs>http://blogs.law.harvard.edu/tech/rss</docs>
      <generator>Easy_RSS</generator>
      <managingEditor>$managingEditor</managingEditor>
      <webMaster>$webMaster</webMaster>
|;

# Read and Print TSV File Data
# This assumes data stored in the TSV file as follows:

open IN,"$TSVfile" or die "Cannot open file.";
my $count = 0; my @elements; while (<IN>) {
	chomp; my $item;
	if ($count == 0) { @elements = split "\t",$_;  }
	else {
		@itemcontents = split "\t",$_;
		my $itemcount = 0;
		foreach my $e (@elements) { 
			$itemcontents[$itemcount] = &rssify($itemcontents[$itemcount]);
			$item->{lc($e)} = $itemcontents[$itemcount];
			$itemcount++;
		}
		unless ($item->{pubDate}) { $item->{pubDate} = &rfc822_date(time); }
		unless ($item->{guid}) { $item->{guid} = $item->{link}; }
		print qq|    <item>
	 <title>$item->{title}</title>
 	 <link>$item->{link}</link>
       <pubDate>$item->{pubDate}</pubDate>
       <guid>$item->{guid}</guid>
	 <description><![CDATA[ $item->{description} ]]></description>
    </item>
		|;
	}
	$count++;
}					 

print "</channel></rss>";

exit;

sub rssify {

	my ($string) = @_;


	$string =~ s/&(\w+?);/AMPERSAND$1; /g;
	$string =~ s/&/&amp;/mig;
	$string =~ s/AMPERSAND(\w+?);/&$1;/g;

	return $string;
}


sub rfc822_date {

	# Get date from input
	my ($current) = @_; my $date;

	# Just return it if it's not a date number
	if (($current+0) == 0) { return $current; }

	my @days =
		('Sun','Mon','Tue','Wed','Thu','Fri','Sat');
  	my @months =
		('Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');

	# Extract values for date
	my ($sec,$min,$hour,$mday,$mon,
		$year,$wday,$yday,$isdst) = localtime($current);

	# Y2K
	$year = $year - 100;
	if ($year < 0) { $year = 2000+$year; }
	elsif ($year == 0) { $year = "2000"; }
	else { $year = 2000+$year; }

	if ($hour < 10) { $hour = "0" . $hour; }
	if ($min < 10) { $min = "0" . $min; }
	if ($sec < 10) { $sec = "0" . $sec; }

	return "$days[$wday], $mday $months[$mon] $year $hour:$min:$sec -0400";
}