Dancer2::Plugin::Auth::Tiny - Require logged-in user for specified routes


version 0.008


  use Dancer2::Plugin::Auth::Tiny;

  get '/private' => needs login => sub { ... };

  get '/login' => sub {
    # put 'return_url' in a hidden form field
    template 'login' => { return_url => params->{return_url} };

  post '/login' => sub {
    if ( _is_valid( params->{user}, params->{password} ) ) {
      session user => params->{user};
      return redirect params->{return_url} || '/';
    else {
      template 'login' => { error => "invalid username or password" };

  sub _is_valid { ... } # this is up to you


This Dancer2 plugin provides an extremely simple way of requiring that a user be logged in before allowing access to certain routes.

It is not "Tiny" in the usual CPAN sense, but it is "Tiny" with respect to Dancer2 authentication plugins. It provides very simple sugar to wrap route handlers with an authentication closure.

The plugin provides the needs keyword and a default login wrapper that you can use like this:

  get '/private' => needs login => $coderef;

The code above is roughly equivalent to this:

  get '/private' => sub {
    if ( session 'user' ) {
      goto $coderef;
    else {
      return redirect uri_for( '/login',
        { return_url => uri_for( request->path, request->params ) } );

It is up to you to provide the '/login' route, handle actual authentication, and set user session variable if login is successful.

If the original request contains a parameter in the passthrough list, it will be added to the login query. For example, will be redirected as This facilitates pre-populating a login form.


You may override any of these settings:

  • login_route: /login -- defines where a protected route is redirected

  • logged_in_key: user -- defines the session key that must be true to indicate a logged-in user

  • callback_key: return_url -- defines the parameter key with the original request URL that is passed to the login route

  • passthrough: - user -- a list of parameters that should be passed through to the login handler


The class method extend may be used to add (or override) authentication criteria. For example, to add a check for the session 'is_admin' key:

    admin => sub {
      my ($dsl, $coderef) = @_;
      return sub {
        if ( $dsl->app->session->read("is_admin") ) {
          goto $coderef;
        else {
          $dsl->app->redirect '/access_denied';

  get '/super_secret' => needs admin => sub { ... };

It takes key/value pairs where the value must be a closure generator that wraps arguments passed to needs.

You could pass additional arguments before the code reference like so:

  # don't conflict with Dancer2's any()
  use Syntax::Keyword::Junction 'any' => { -as => 'any_of' };

    any_role => sub {
      my $coderef = pop;
      my ($dsl, @requested_roles) = @_;
      return sub {
        my @user_roles = @{ $dsl->app->session->read("roles") || [] };
        if ( any_of(@requested_roles) eq any_of(@user_roles) ) {
          goto $coderef;
        else {
          $dsl->app->redirect '/access_denied';

  get '/parental' => needs any_role => qw/mom dad/ => sub { ... };


For more complex Dancer2 authentication, see:

For password authentication algorithms for your own '/login' handler, see:


This simplified Auth module was inspired by Dancer::Plugin::Auth::Extensible by David Precious and discussions about its API by members of the Dancer Users mailing list.


Bugs / Feature Requests

Please report any bugs or feature requests through the issue tracker at You will be notified automatically of any progress on your issue.

Source Code

This is open source software. The code repository is available for public review and contribution under the terms of the license.

  git clone


  • David Golden <>

  • Sawyer X <>


  • Jason A. Crome <>

  • Jim Davis <>

  • Pedro Melo <>

  • Peter Mottram <>


This software is Copyright (c) 2016 by David Golden.

This is free software, licensed under:

  The Apache License, Version 2.0, January 2004