shows facebook feed URL

facebook-feed.pl

#!/usr/bin/env perl
#
# facebook-feed.pl - shows facebook feed URL
#
# Shows facebook feed URL.
#
# Usage examples:
# % ./facebook-feed.pl girlsgeneration
# http://www.facebook.com/feeds/page.php?format=atom10&id=216732611680045
# % ./facebook-feed.pl http://www.facebook.com/trycatchpage
# http://www.facebook.com/feeds/page.php?format=atom10&id=301925689927032
#
# Seungwon Jeong <seungwon0@gmail.com>
#
# Copyright (C) 2013 by Seungwon Jeong
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see
# <http://www.gnu.org/licenses/>.

use perl5i::2;

use IO::All;

use Encode < decode_utf8 >;

use JSON < decode_json >;

use Readonly;

if ( @ARGV != 1 ) {
    say "Usage: $PROGRAM_NAME FACEBOOK_ID";
    exit 2;
}

my $facebook_id = $ARGV[0];

# Remove trailing '/'.
$facebook_id =~ s{ / $ }{}xms;

# http://www.facebook.com/trycatchpage -> trycatchpage
$facebook_id =~ s{ ^ .* / }{}xms;

my $url = 'http://graph.facebook.com/' . $facebook_id;

my $document = decode_utf8( io($url)->all );

my $graph_ref = decode_json($document);

Readonly my $FORMAT => 'atom10';    # or 'rss20'

my $feed_url
    = "http://www.facebook.com/feeds/page.php?format=$FORMAT&id="
    . $graph_ref->{id};

say $feed_url;