3 Catalyst::Manual::Tutorial::Authorization - Catalyst Tutorial - Part 5: Authorization
8 This is B<Part 5 of 9> for the Catalyst tutorial.
10 L<Tutorial Overview|Catalyst::Manual::Tutorial>
16 L<Introduction|Catalyst::Manual::Tutorial::Intro>
20 L<Catalyst Basics|Catalyst::Manual::Tutorial::CatalystBasics>
24 L<Basic CRUD|Catalyst::Manual::Tutorial_BasicCRUD>
28 L<Authentication|Catalyst::Manual::Tutorial::Authentication>
36 L<Debugging|Catalyst::Manual::Tutorial::Debugging>
40 L<Testing|Catalyst::Manual::Tutorial::Testing>
44 L<AdvancedCRUD|Catalyst::Manual::Tutorial::AdvancedCRUD>
48 L<Appendices|Catalyst::Manual::Tutorial::Appendices>
56 This part of the tutorial adds role-based authorization to the existing
57 authentication implemented in Part 4. It provides simple examples of
58 how to use roles in both TT templates and controller actions. The first
59 half looks at manually configured authorization. The second half looks
60 at how the ACL authorization plugin can simplify your code.
62 B<TIP>: Note that all of the code for this part of the tutorial can be
63 pulled from the Catalyst Subversion repository in one step with the
66 svn checkout http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/Tutorial@###
67 IMPORTANT: Does not work yet. Will be completed for final version.
70 =head1 BASIC AUTHORIZATION
72 In this section you learn how to manually configure authorization.
74 =head2 Update Plugins to Include Support for Authorization
76 Edit C<lib/MyApp.pm> and add C<Authorization::Roles> to the list:
88 Authentication::Store::DBIC
89 Authentication::Credential::Password
93 Session::Store::FastMmap
94 Session::State::Cookie
98 =head2 Add Config Information for Authorization
100 Edit C<myapp.yml> and update it to match (everything from the
101 "authorization:" line down is new):
107 # Note this first definition would be the same as setting
108 # __PACKAGE__->config->{authentication}->{dbic}->{user_class} = 'MyAppDB::User'
109 # in lib/MyApp.pm (IOW, each hash key becomes a "name:" in the YAML file).
111 # This is the model object created by Catalyst::Model::DBIC from your
112 # schema (you created 'MyAppDB::User' but as the Catalyst startup
113 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::User').
114 # NOTE: Omit 'MyAppDB::Model' to avoid a component lookup issue in Catalyst 5.66
115 user_class: MyAppDB::User
116 # This is the name of the field in your 'users' table that contains the user's name
118 # This is the name of the field in your 'users' table that contains the password
119 password_field: password
120 # Other options can go here for hashed passwords
121 # Enabled hashed passwords
122 password_type: hashed
123 # Use the SHA-1 hashing algorithm
124 password_hash_type: SHA-1
127 # This is the model object created by Catalyst::Model::DBIC from your
128 # schema (you created 'MyAppDB::Role' but as the Catalyst startup
129 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::Role').
130 # NOTE: Omit 'MyAppDB::Model' to avoid a component lookup issue in Catalyst 5.66
131 role_class: MyAppDB::Role
132 # The name of the field in the 'roles' table that contains the role name
134 # The name of the accessor used to map a user to a role
135 # See the has_many() in MyAppDB/User.pm
136 role_rel: map_user_role
137 # The name of the field in the user_role table that references the user
138 user_role_user_field: user_id
141 =head2 Add Role-Specific Logic to the "Book List" Template
143 Open C<root/src/books/list.tt2> in your editor and add the following
144 lines to the bottom of the file:
146 <p>Hello [% Catalyst.user.username %], you have the following roles:</p>
149 [% # Dump list of roles -%]
150 [% FOR role = Catalyst.user.roles %]<li>[% role %]</li>[% END %]
154 [% # Add some simple role-specific logic to template %]
155 [% # Use $c->check_user_roles() to check authz -%]
156 [% IF Catalyst.check_user_roles('user') %]
157 [% # Give normal users a link for 'logout' %]
158 <a href="[% Catalyst.uri_for('/logout') %]">Logout</a>
161 [% # Can also use $c->user->check_roles() to check authz -%]
162 [% IF Catalyst.check_user_roles('admin') %]
163 [% # Give admin users a link for 'create' %]
164 <a href="[% Catalyst.uri_for('form_create') %]">Create</a>
168 This code displays a different combination of links depending on the
169 roles assigned to the user.
171 =head2 Limit C<Books::add> to C<admin> Users
173 C<IF> statements in TT templates simply control the output that is sent
174 to the user's browser; it provides no real enforcement (if users know or
175 guess the appropriate URLs, they are still perfectly free to hit any
176 action within your application). We need to enhance the controller
177 logic to wrap restricted actions with role-validation logic.
179 For example, we might want to restrict the "formless create" action to
180 admin-level users by editing C<lib/MyApp/Controller/Books.pm> and
181 updating C<url_create> to match the following code:
185 Create a book with the supplied title and rating,
186 with manual authorization
190 sub url_create : Local {
191 # In addition to self & context, get the title, rating & author_id args
192 # from the URL. Note that Catalyst automatically puts extra information
193 # after the "/<controller_name>/<action_name/" into @_
194 my ($self, $c, $title, $rating, $author_id) = @_;
196 # Check the user's roles
197 if ($c->check_user_roles('admin')) {
198 # Call create() on the book model object. Pass the table
199 # columns/field values we want to set as hash values
200 my $book = $c->model('MyAppDB::Book')->create({
205 # Add a record to the join table for this book, mapping to
207 $book->add_to_book_authors({author_id => $author_id});
208 # Note: Above is a shortcut for this:
209 # $book->create_related('book_authors', {author_id => $author_id});
211 # Assign the Book object to the stash for display in the view
212 $c->stash->{book} = $book;
214 # This is a hack to disable XSUB processing in Data::Dumper
215 # (it's used in the view). This is a work-around for a bug in
216 # the interaction of some versions or Perl, Data::Dumper & DBIC.
217 # You won't need this if you aren't using Data::Dumper (or if
218 # you are running DBIC 0.06001 or greater), but adding it doesn't
219 # hurt anything either.
220 $Data::Dumper::Useperl = 1;
222 # Set the TT template to use
223 $c->stash->{template} = 'books/create_done.tt2';
225 # Provide very simple feedback to the user
226 $c->response->body('Unauthorized!');
231 To add authorization, we simply wrap the main code of this method in an
232 C<if> statement that calls C<check_user_roles>. If the user does not
233 have the appropriate permissions, they receive an "Unauthorized!"
234 message. Note that we intentionally chose to display the message this
235 way to demonstrate that TT templates will not be used if the response
236 body has already been set. In reality you would probably want to use a
237 technique that maintains the visual continuity of your template layout
238 (for example, using the "status" or "error" message feature added in
241 B<TIP>: If you want to keep your existing C<url_create> method, you can
242 create a new copy and comment out the original by making it look like a
243 Pod comment. For example, put something like C<=begin> before C<sub add
244 : Local {> and C<=end> after the closing C<}>.
246 =head2 Try Out Authentication And Authorization
248 Press C<Ctrl-C> to kill the previous server instance (if it's still
249 running) and restart it:
251 $ script/myapp_server.pl
253 Now trying going to L<http://localhost:3000/books/list> and you should
254 be taken to the login page (you might have to C<Shift+Reload> your
255 browser). Try logging in with both C<test01> and C<test02> (both use a
256 password of C<mypass>) and notice how the roles information updates at
257 the bottom of the "Book List" page. Also try the C<Logout> link on the
260 Now the "url_create" URL will work if you are already logged in as user
261 C<test01>, but receive an authorization failure if you are logged in as
264 http://localhost:3000/books/url_create/test/1/6
266 while logged in as each user. Use one of the 'Logout' links (or go to
267 L<http://localhost:3000/logout> in you browser directly) when you are
270 =head1 ENABLE ACL-BASED AUTHORIZATION
272 This section takes a brief look at how the
273 L<Catalyst::Plugin::Authorization::ACL> plugin can automate much of the
274 work required to perform role-based authorization in a Catalyst
277 =head2 Add the C<Catalyst::Plugin::Authorization::ACL> Plugin
279 Open C<lib/MyApp.pm> in your editor and add the following plugin to the
280 C<use Catalyst> statement:
284 Note that the remaining C<use Catalyst> plugins from earlier sections
285 are not shown here, but they should still be included.
287 =head2 Add ACL Rules to the Application Class
289 Open C<lib/MyApp.pm> in your editor and add the following B<BELOW> the
290 C<__PACKAGE__-E<gt>setup;> statement:
292 # Authorization::ACL Rules
293 __PACKAGE__->deny_access_unless(
294 "/books/form_create",
297 __PACKAGE__->deny_access_unless(
298 "/books/form_create_do",
301 __PACKAGE__->deny_access_unless(
306 Each of the three statements above comprises an ACL plugin "rule". The
307 first two rules only allow admin-level users to create new books using
308 the form (both the form itself and the data submission logic are
309 protected). The third statement allows both users and admin to delete
310 books. The C</books/url_create> action will continue to be protected by
311 the "manually configured" authorization created earlier in this part of
314 The ACL plugin permits you to apply allow/deny logic in a variety of
315 ways. The following provides a basic overview of the capabilities:
321 The ACL plugin only operates on the Catalyst "private namespace". You
322 are using the private namespace when you use C<Local> actions. C<Path>,
323 C<Regex>, and C<Global> allow you to specify actions where the path and
324 the namespace differ -- the ACL plugin will not work in these cases.
328 Each rule is expressed in a separate
329 C<__PACKAGE__-E<gt>deny_access_unless()> or
330 C<__PACKAGE__-E<gt>allow_access_if()> line (there are several other
331 methods that can be used for more complex policies, see the C<METHODS>
333 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
334 documentation for more details).
338 Each rule can contain multiple roles but only a single path.
342 The rules are tried in order (with the "most specific" rules tested
343 first), and processing stops at the first "match" where an allow or deny
344 is specified. Rules "fall through" if there is not a "match" (where a
345 "match" means the user has the specified role). If a "match" is found,
346 then processing stops there and the appropriate allow/deny action is
351 If none of the rules match, then access is allowed.
355 The rules currently need to be specific in the application class
356 C<lib\MyApp.pm> B<after> the C<__PACKAGE__-E<gt>setup;> line.
360 =head2 Add a Method to Handle Access Violations
363 L<Catalyst::Plugin::Authorization::ACL>
364 throws an exception when authorization fails. This will take the user
365 to the Catalyst debug screen, or a "Please come back later" message if
366 you are not using the C<-Debug> flag. This step uses the
367 C<access_denied> method in order to provide more appropriate feedback to
370 Open C<lib/MyApp/Controller/Books.pm> in your editor and add the
375 Handle Catalyst::Plugin::Authorization::ACL access denied exceptions
379 sub access_denied : Private {
382 # Set the error message
383 $c->stash->{error_msg} = 'Unauthorized!';
390 Then run the Catalyst development server script:
392 $ script/myapp_server.pl
394 Log in as C<test02>. Once at the book list, click the "Create" link to
395 try the C<form_create> action. You should receive a red "Unauthorized!"
396 error message at the top of the list. (Note that in reality you would
397 probably want to place the "Create" link code in
398 C<root/src/books/list.tt2> inside an C<IF> statement that only displays
399 the list to admin-level users.) If you log in as C<test01> you should
400 be able to view the C<form_create> form and add a new book.
402 When you are done, use one of the 'Logout' links (or go to the
403 L<http://localhost:3000/logout> URL directly) when you are done.
408 Kennedy Clark, C<hkclark@gmail.com>
410 Please report any errors, issues or suggestions to the author.
412 Copyright 2006, Kennedy Clark, under Creative Commons License
413 (L<http://creativecommons.org/licenses/by-nc-sa/2.5/>).