Update Plugins to Include Support for Authorization

    # Load plugins
    use Catalyst qw/
        -Debug
        ConfigLoader
        Static::Simple

        StackTrace

        Authentication
        Authorization::Roles

        Session
        Session::Store::File
        Session::State::Cookie

        StatusMessage
    /;

Once again, include this additional plugin as a new dependency in the Makefile.PL file like this:

    requires 'Catalyst::Plugin::Authorization::Roles';

Add Role-Specific Logic to the "Book List" Template

    ...
    <p>Hello [% c.user.username %], you have the following roles:</p>

    <ul>
      [% # Dump list of roles -%]
      [% FOR role = c.user.roles %]<li>[% role %]</li>[% END %]
    </ul>

    <p>
    [% # Add some simple role-specific logic to template %]
    [% # Use $c->check_user_roles() to check authz -%]
    [% IF c.check_user_roles('user') %]
      [% # Give normal users a link for 'logout' %]
      <a href="[% c.uri_for('/logout') %]">User Logout</a>
    [% END %]

    [% # Can also use $c->user->check_roles() to check authz -%]
    [% IF c.check_user_roles('admin') %]
      [% # Give admin users a link for 'create' %]
      <a href="[% c.uri_for(c.controller.action_for('form_create')) %]">Admin Create</a>
    [% END %]
    </p>

This code displays a different combination of links depending on the roles assigned to the user.

Limit Books::add to 'admin' Users

For example, we might want to restrict the "formless create" action to admin-level users by editing "lib/MyApp/Controller/Books.pm" and updating "url_create" to match the following code:

    =head2 url_create

    Create a book with the supplied title and rating,
    with manual authorization

    =cut

    sub url_create :Chained('base') :PathPart('url_create') :Args(3) {
        # In addition to self & context, get the title, rating & author_id args
        # from the URL.  Note that Catalyst automatically puts extra information
        # after the "/<controller_name>/<action_name/" into @_
        my ($self, $c, $title, $rating, $author_id) = @_;

        # Check the user's roles
        if ($c->check_user_roles('admin')) {
            # Call create() on the book model object. Pass the table
            # columns/field values we want to set as hash values
            my $book = $c->model('DB::Book')->create({
                    title   => $title,
                    rating  => $rating
                });

            # Add a record to the join table for this book, mapping to
            # appropriate author
            $book->add_to_book_authors({author_id => $author_id});
            # Note: Above is a shortcut for this:
            # $book->create_related('book_authors', {author_id => $author_id});

            # Assign the Book object to the stash and set template
            $c->stash(book     => $book,
                      template => 'books/create_done.tt2');
        } else {
            # Provide very simple feedback to the user.
            $c->response->body('Unauthorized!');
        }
    }

To add authorization, we simply wrap the main code of this method in an "if" statement that calls "check_user_roles". If the user does not have the appropriate permissions, they receive an "Unauthorized!" message. Note that we intentionally chose to display the message this way to demonstrate that TT templates will not be used if the response body has already been set. In reality you would probably want to use a technique that maintains the visual continuity of your template layout (for example, using Catalyst::Plugin::StatusMessage as shown in the last chapter to redirect to an "unauthorized" page).

TIP: If you want to keep your existing "url_create" method, you can create a new copy and comment out the original by making it look like a Pod comment. For example, put something like "=begin" before "sub add : Local {" and "=end" after the closing "}".

Try Out Authentication And Authorization

    $ script/myapp_server.pl -r

Now trying going to <http://localhost:3000/books/list> and you should be taken to the login page (you might have to "Shift+Reload" or "Ctrl+Reload" your browser and/or click the "User Logout" link on the book list page). Try logging in with both "test01" and "test02" (both use a password of "mypass") and notice how the roles information updates at the bottom of the "Book List" page. Also try the "User Logout" link on the book list page.

Now the "url_create" URL will work if you are already logged in as user "test01", but receive an authorization failure if you are logged in as "test02". Try:

    http://localhost:3000/books/url_create/test/1/6

while logged in as each user. Use one of the "logout" links (or go to <http://localhost:3000/logout> in your browser directly) when you are done.