Run a facebook post like a Web Application.

facebook.pm

package facebook;
use Plack::Request;
use Plack::Response;
use Plack::Runner;
use Plack::App::URLMap;
use URI::Escape;
use LWP::Simple;
use JSON;
use HTML::Entities;
use Encode;

my $id;
use overload "/" => sub { $id = $_[1]; $_[0] }, fallback => 1;

sub import {
    my $pkg = caller;
    *{"$pkg\::com"} = *{"$pkg\::posts"} = sub() { bless {}, __PACKAGE__ };
}

my $app_id = $ENV{RUNFB_APP_ID};
my $app_secret = $ENV{RUNFB_APP_SECRET};

my $app_redirect = sub {
    my $req = Plack::Request->new(shift);
    my $uri = uri_escape_utf8( $req->base . 'callback' );
    my $redirect_url = "http://www.facebook.com/dialog/oauth?"
        . "client_id=$app_id&redirect_uri=$uri&scope=read_stream";
    my $res = Plack::Response->new(302);
    $res->redirect($redirect_url);
    return $res->finalize;
};

my $app_callback = sub {
    my $req = Plack::Request->new(shift);
    my $code = $req->param('code');
    my $uri = uri_escape_utf8( $req->base );
    my $token_url = "https://graph.facebook.com/oauth/access_token?" 
        . "client_id=$app_id&redirect_uri=$uri&client_secret=$app_secret&code=$code";
    my $access_token = get($token_url);
    my $json = get("https://graph.facebook.com/$id?$access_token");

    my $data = decode_json($json);
    my $message = $data->{message};
    my $result;
    {
        local *STDOUT;
        open STDOUT, '>', \$result;
        eval $message;
    }
    my $res = Plack::Response->new(200);
    $res->content_type('text/html');
    $res->body(encode_utf8($result));
    return $res->finalize;
};

END {
    my $urlmap = Plack::App::URLMap->new;
    $urlmap->map( '/' => $app_redirect );
    $urlmap->map( '/callback' => $app_callback );
    my $app = $urlmap->to_app;
    my $runner = Plack::Runner->new;
    $runner->parse_options(@ARGV);
    $runner->run($app);
}