tutorial : a complete dancer app

dancr.pl

 use Dancer;
 use DBI;
 use File::Spec;
 use File::Slurp;
 use Template;
 
 set 'database' => File::Spec->tmpdir() . '/dancr.db';
 set 'session' => 'Simple';
 set 'template' => 'template_toolkit';
 set 'logger' => 'console';
 set 'log' => 'debug';
 set 'show_errors' => 1;
 set 'access_log' => 1;
 set 'warnings' => 1;
 set 'username' => 'admin';
 set 'password' => 'password';
 
 layout 'main';
 
 my $flash;
 
 sub set_flash {
 	my $message = shift;
 
 	$flash = $message;
 }
 
 sub get_flash {
 
 	my $msg = $flash;
 	$flash = "";
 
 	return $msg;
 }
 
 sub connect_db {
 	my $dbh = DBI->connect("dbi:SQLite:dbname=".setting('database')) or
 		die $DBI::errstr;
 
 	return $dbh;
 }
 
 sub init_db {
 	my $db = connect_db();
 	my $schema = read_file('./schema.sql');
 	$db->do($schema) or die $db->errstr;
 }
 
 before_template sub {
 	my $tokens = shift;
 	
 	$tokens->{'css_url'} = request->base . 'css/style.css';
 	$tokens->{'login_url'} = uri_for('/login');
 	$tokens->{'logout_url'} = uri_for('/logout');
 };
 
 get '/' => sub {
 	my $db = connect_db();
 	my $sql = 'select id, title, text from entries order by id desc';
 	my $sth = $db->prepare($sql) or die $db->errstr;
 	$sth->execute or die $sth->errstr;
 	template 'show_entries.tt', { 
 		'msg' => get_flash(),
 		'add_entry_url' => uri_for('/add'),
 		'entries' => $sth->fetchall_hashref('id'),
 	};
 };
 
 post '/add' => sub {
 	if ( not session('logged_in') ) {
 		send_error("Not logged in", 401);
 	}
 
 	my $db = connect_db();
 	my $sql = 'insert into entries (title, text) values (?, ?)';
 	my $sth = $db->prepare($sql) or die $db->errstr;
 	$sth->execute(params->{'title'}, params->{'text'}) or die $sth->errstr;
 
 	set_flash('New entry posted!');
 	redirect '/';
 };
 
 any ['get', 'post'] => '/login' => sub {
 	my $err;
 
 	if ( request->method() eq "POST" ) {
 		# process form input
 		if ( params->{'username'} ne setting('username') ) {
 			$err = "Invalid username";
 		}
 		elsif ( params->{'password'} ne setting('password') ) {
 			$err = "Invalid password";
 		}
 		else {
 			session 'logged_in' => true;
 			set_flash('You are logged in.');
 			redirect '/';
 		}
	}

	# display login form
	template 'login.tt', { 
		'err' => $err,
	};

 };

 get '/logout' => sub {
	session->destroy;
	set_flash('You are logged out.');
	redirect '/';
 };

 init_db();
 start;