NAME

       CGI::Application::Plugin::Authorization - Authorization framework for CGI::Application

SYNOPSIS

        use base qw(CGI::Application);
        use CGI::Application::Plugin::Authentication;
        use CGI::Application::Plugin::Authorization;

        # default config for runmode authorization
        __PACKAGE__->authz->config(
            DRIVER => [ 'HTGroup', FILE => 'htgroup' ],
        );

        # Using a named configuration to distinguish it from
        # the above configuration
        __PACKAGE__->authz('dbaccess')->config(
            DRIVER => [ 'DBI',
                DBH   => $self->dbh,
                TABLES      => ['user', 'access'],
                JOIN_ON     => 'user.id = access.user_id',
                CONSTRAINTS => {
                    'user.name'      => '__USERNAME__',
                    'access.table'   => '__PARAM_1__',
                    'access.item_id' => '__PARAM_2__'
                }
            ],
        );

        sub admin_runmode {
           my $self = shift;

           # User must be in the admin group to have access to this runmode
           return $self->authz->forbidden unless $self->authz->authorize('admin');

           # rest of the runmode
           ...
        }

        sub update_widget {
           my $self = shift;
           my $widget = $self->query->param('widget_id');

           # Can this user edit this widget in the widgets table?
           return $self->authz->forbidden unless $self->authz('dbaccess')->authorize(widgets => $widget);

           # save changes to the widget
           ...
        }

DESCRIPTION

       CGI::Application::Plugin::Authorization adds the ability to authorize users for specific tasks.  Once a
       user has been authenticated and you know who you are dealing with, you can then use this plugin to
       control what that user has access to.  It imports two methods ("authz" and "authorization") into your
       CGI::Application module.  Both of these methods are interchangeable, so you should choose one and use it
       consistently throughout your code.  Through the authz method you can call all the methods of the
       CGI::Application::Plugin::Authorization plugin.

   Named Configurations
       There could be multiple ways that you may want to authorize actions in different parts of your code.
       These differences may conflict with each other.  For example you may have runmode level authorization
       that requires that the user belongs to a certain group.  But secondly, you may have row level database
       authorization that requires that the username column of the table contains the name of the current user.
       These configurations would conflict with each other since they are authorizing using different
       information.  To solve this you can create multiple named configurations, by specifying a unique name to
       the c<authz> method.

        __PACKAGE__->authz('dbaccess')->config(
            DRIVER => [ 'DBI', ... ],
        );
        # later
        $self->authz('dbaccess')->authorize(widgets => $widget_id);

EXPORTED METHODS

   authz -and- authorization
       These methods are interchangeable and provided for users that either prefer brevity, or clarity.
       Everything is controlled through this method call, which will return a
       CGI::Application::Plugin::Authorization object, or just the class name if called as a class method.  When
       using the plugin, you will always first call $self->authz or __PACKAGE__->authz and then the method you
       wish to invoke.  You can create multiple named authorization modules by providing a unique name to the
       call to authz.  This will allow you to handle different types of authorization in your modules.  For
       example, you could use the main configuration to do runmode level authorization, and use a named
       configuration to manage database row level authorization.

METHODS

   config
       This method is used to configure the CGI::Application::Plugin::Authorization module.  It can be called as
       an object method, or as a class method.

       The following parameters are accepted:

       DRIVER
           Here you can choose which authorization module(s) you want to use to perform the authorization.  For
           simplicity, you can leave off the CGI::Application::Plugin::Authorization::Driver:: part when
           specifying the DRIVER parameter.  If this module requires extra parameters, you can pass an array
           reference that contains as the first parameter the name of the module, and the required parameters as
           the rest of the array.  You can provide multiple drivers which will be used, in order, to check the
           permissions until a valid response is received.

             DRIVER => [ 'DBI', dbh => $self->dbh ],

             - or -

             DRIVER => [
               [ 'HTGroup', file => '.htgroup' ],
               [ 'LDAP', binddn => '...', host => 'localhost', ... ]
             ],

       FORBIDDEN_RUNMODE
           Here you can specify a runmode that the user will be redirected to if they fail the authorization
           checks.

             FORBIDDEN_RUNMODE => 'forbidden'

       FORBIDDEN_URL
           If your forbidden page is external to this module, then you can use this option to specify a URL that
           the user will be redirected to when they fail the authorization checks. If both FORBIDDEN_URL and
           FORBIDDEN_RUNMODE are specified, then the latter will take precedence.

             FORBIDDEN_URL => 'http://example.com/forbidden.html'

       GET_USERNAME
           This option allows you to provide a method that should return us the username of the currently logged
           in user.  It will be passed the current authz objects as the only parameter.  This is not a required
           option, and can be omitted if you use the Authentication plugin, or if your authentication system
           sets $ENV{REMOTE_USER}.

             GET_USERNAME => sub { my $authz = shift; return $authz->cgiapp->my_username }

   authz_runmodes
       This method takes a list of runmodes that are to be authorized, and the authorization rules for said
       runmodes.  If a user tries to access one of these runmodes, then they will be redirected to the forbidden
       page unless authorization is granted.

       The runmode names can be simple strings, regular expressions, coderefs (which are passed the name of the
       runmode as their only parameter), or special directives that start with a colon.

       The authorization rules can be simple strings representing the name of the group that the user must be a
       member of, as a list-ref of group names (of which the user only has to be a member of any one of the
       groups, or as a code-ref that will be called (with no parameters).

       This method is cumulative, so if it is called multiple times, the new values are appended to the list of
       existing entries.  It returns a list containing all of the entries that have been configured thus far.

       NOTE: compatibility with the interface as was defined in 0.06 is preserved.  0.06 allowed for runmodes to
       be passed in as a list-ref of two-element lists to specify authorization rules.  Although this interface
       is supported, the extra list-refs aren't necessary.

       :all - All runmodes in this module will require authorization

         # match all runmodes
         __PACKAGE__->authz->authz_runmodes(
             ':all' => 'admin',
             );

         # only protect runmodes one and two
         __PACKAGE__->authz->authz_runmodes(
             one => 'admin',
             two => 'admin',
             );

         # protect only runmodes that start with auth_
         __PACKAGE__->authz->authz_runmodes(
             qr/^authz_/ => 'admin',
             );

         # protect all runmodes that *do not* start with public_
         __PACKAGE__->authz->authz_runmodes(
             qr/^(?!public_)/ => 'admin',
             );

         # preserve the interface from 0.06:
         __PACKAGE__->authz->authz_runmodes(
             [':all' => 'admin'],
             );

   is_authz_runmode
       This method accepts the name of a runmode, and if that runmode requires authorization (ie the user needs
       to be a member of a particular group or has to satisfy some other authorization rule) then this method
       returns the corresponding authorization rule which must be satisfied (which could be either a scalar, a
       list-ref, or a code-ref, depending on how the rules were defined).

   new
       This method creates a new CGI::Application::Plugin::Authorization object.  It requires as it's only
       parameter a CGI::Application object.  This method should never be called directly, since the "authz"
       method that is imported into the CGI::Application module will take care of creating the
       CGI::Application::Plugin::Authorization object when it is required.

   instance
       This method works the same way as "new", except that it returns the same Authorization object for the
       duration of the request.  This method should never be called directly, since the "authz" method that is
       imported into the CGI::Application module will take care of creating the
       CGI::Application::Plugin::Authorization object when it is required.

   authorize
       This method will test to see if the current user has access to the given resource.  It will take the
       given parameters and test them against the DRIVER classes that have been configured.  A true return value
       means the user should have access to the given resource.

        # is the current user in the admin group
        if ($self->authz->authorize('admingroup')) {
           # perform an admin action
        }

   username
       This method will return the name of the currently logged in user.  It uses three different methods to
       figure out the username:

       GET_USERNAME option
           Use the subroutine provided by the GET_USERNAME option to figure out the current username

       CGI::Application::Plugin::Authentication
           See if the CGI::Application::Plugin::Authentication plugin is being used, and retrieve the username
           through this plugin

       REMOTE_USER
           See if the REMOTE_USER environment variable is set and use that value

   drivers
       This method will return a list of driver objects that are used for this authorization instance.

   cgiapp
       This will return the underlying CGI::Application object.

   setup_runmodes
       This method is called during the prerun stage to register some custom runmodes that the Authentication
       plugin requires in order to function.

CGI::Application CALLBACKS

       We'll automatically add the "authz_forbidden" run mode if you are using CGI::Application 4.0 or greater.

       If you are using an older version of CGI::Application you will need to add it yourself.

        sub cgiapp_prerun {
           my $self = shift;

           $self->run_modes( authz_forbidden => \&CGI::Application::Plugin::Authorization::authz_forbidden, );
        }

   prerun_callback
       This method is a CGI::Application prerun callback that will be automatically registered for you if you
       are using CGI::Application 4.0 or greater.  If you are using an older version of CGI::Application you
       will have to create your own cgiapp_prerun method and make sure you call this method from there.

        sub cgiapp_prerun {
           my $self = shift;

           $self->CGI::Application::Plugin::Authorization::prerun_callback();
        }

   redirect_to_forbidden
       This method is be called during the prerun stage if the current user is not authorized, and they are
       trying to access an authz runmode.  It will redirect to the page that has been configured as the
       forbidden page, based on the value of FORBIDDEN_RUNMODE or FORBIDDEN_URL  If nothing is configured then
       the default forbidden page will be used.

   forbidden
       This will return a forbidden page.  It checks the configuration to see if there is a custom runmode or
       URL to redirect to, otherwise it calls the builtin authz_forbidden runmode.

CGI::Application RUNMODES

   authz_forbidden
       This runmode is provided if you do not want to create your own forbidden runmode.  It will display a
       simple error page to the user.

   authz_dummy_redirect
       This runmode is provided for convenience when an external redirect needs to be done.  It just returns an
       empty string.

EXAMPLE

       In a CGI::Application module:

         package MyCGIApp;

         use base qw(CGI::Application);
         use CGI::Application::Plugin::AutoRunmode;
         use CGI::Application::Plugin::Authentication;
         use CGI::Application::Plugin::Authorization;

         # Configure Authentication
         MyCGIApp->authen->config(
               DRIVER => 'Dummy',
         );
         MyCGIApp->authen->protected_runmodes(qr/^admin_/);

         # Configure Authorization (manages runmode authorization)
         MyCGIApp->authz->config(
             DRIVER => [ 'DBI',
                 DBH         => $self->dbh,
                 TABLES      => ['user', 'usergroup', 'group'],
                 JOIN_ON     => 'user.id = usergroup.user_id AND usergroup.group_id = group.id',
                 CONSTRAINTS => {
                    'user.name'  => '__USERNAME__',
                    'group.name' => '__GROUP__',
                 }
             ],
         );
         MyCGIApp->authz->authz_runmodes(
            [a_runmode => 'a_group'],
            [qr/^admin_/ => 'admin'],
            [':all' => 'all_group'],
            [sub {my $rm = shift; return ($rm eq "dangerous_rm")} => 'super_group'],
         );

         # Configure second Authorization module using a named configuration
         __PACKAGE__->authz('dbaccess')->config(
             DRIVER => [ 'DBI',
                 DBH   => $self->dbh,
                 TABLES      => ['user', 'access'],
                 JOIN_ON     => 'user.id = access.user_id',
                 CONSTRAINTS => {
                     'user.name'      => '__USERNAME__',
                     'access.table'   => '__PARAM_1__',
                     'access.item_id' => '__PARAM_2__'
                 }
             ],
         );

         sub start : Runmode {
           my $self = shift;

         }

         sub admin_one : Runmode {
           my $self = shift;
           # The user will only get here if they are logged in and
           # belong to the admin group

         }

         sub admin_widgets : Runmode {
           my $self = shift;
           # The user will only get here if they are logged in and
           # belong to the admin group

           # Can this user edit this widget in the widgets table?
           my $widget_id = $self->query->param('widget_id');
           return $self->authz->forbidden unless $self->authz('dbaccess')->authorize(widgets => $widget_id);

         }

TODO

       The module is definitely in a usable state, but there are still some parts missing that I would like to
       add in:

       provide easy methods for authorizing runmode access automatically
       allow subroutine attributes to configure authorization for a runmode
       write a tutorial/cookbook to include with the docs

BUGS

       This is alpha software and as such, the features and interface are subject to change.  So please check
       the Changes file when upgrading.

SEE ALSO

       CGI::Application::Plugin::Authentication, CGI::Application, perl(1)

AUTHOR

       Cees Hek <ceeshek@gmail.com>

CREDITS

       Thanks to SiteSuite (http://www.sitesuite.com.au) for funding the development of this plugin and for
       releasing it to the world.

LICENCE AND COPYRIGHT

       Copyright (c) 2005, SiteSuite. All rights reserved.

       This module is free software; you can redistribute it and/or modify it under the same terms as Perl
       itself.

DISCLAIMER OF WARRANTY

       BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT
       PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER
       PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
       INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
       PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE
       SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.

       IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY
       OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE
       TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF
       THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
       RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE
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