Dancer2::Plugin::Auth::Tiny(3)

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

VERSION
version 0.005

SYNOPSIS
  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

DESCRIPTION
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, "http://example.com/private?user=dagolden" will be redirected as "http://example.com/login?user=dagolden&return_url=...". This facilitates pre-populating a login form.

CONFIGURATION
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

EXTENDING
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:

  Dancer2::Plugin::Auth::Tiny->extend(
    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' };

  Dancer2::Plugin::Auth::Tiny->extend(
    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 { ... };

SEE ALSO
For more complex Dancer2 authentication, see:

•   Dancer2::Plugin::Auth::Extensible

•   Dancer2::Plugin::Auth::RBAC -- possibly not yet (or going to be) ported to Dancer2

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

•   Auth::Passphrase

•   Dancer::Plugin::Passphrase -- possibly not yet ported to Dancer2

ACKNOWLEDGMENTS
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.

SUPPORT

  Bugs / Feature Requests
Please report any bugs or feature requests through the issue tracker at <https://github.com/PerlDancer/Dancer2-Plugin-Auth-Tiny/issues>. 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.

<https://github.com/PerlDancer/Dancer2-Plugin-Auth-Tiny>

  git clone https://github.com/PerlDancer/Dancer2-Plugin-Auth-Tiny.git

AUTHORS

•   David Golden <dagolden@cpan.org>

•   Sawyer X <xsawyerx@cpan.org>

CONTRIBUTOR
Pedro Melo <melo@simplicidade.org>

COPYRIGHT AND LICENSE
This software is Copyright (c) 2014 by David Golden.

This is free software, licensed under:

  The Apache License, Version 2.0, January 2004