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@4613 .
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:
86 Authentication::Store::DBIC
87 Authentication::Credential::Password
91 Session::Store::FastMmap
92 Session::State::Cookie
96 =head2 Add Config Information for Authorization
98 Edit C<myapp.yml> and update it to match (everything from the
99 "authorization:" line down is new):
105 # Note this first definition would be the same as setting
106 # __PACKAGE__->config->{authentication}->{dbic}->{user_class} = 'MyAppDB::User'
107 # in lib/MyApp.pm (IOW, each hash key becomes a "name:" in the YAML file).
109 # This is the model object created by Catalyst::Model::DBIC from your
110 # schema (you created 'MyAppDB::User' but as the Catalyst startup
111 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::User').
112 # NOTE: Omit 'MyApp::Model' to avoid a component lookup issue in Catalyst 5.66
113 user_class: MyAppDB::User
114 # This is the name of the field in your 'users' table that contains the user's name
116 # This is the name of the field in your 'users' table that contains the password
117 password_field: password
118 # Other options can go here for hashed passwords
119 # Enabled hashed passwords
120 password_type: hashed
121 # Use the SHA-1 hashing algorithm
122 password_hash_type: SHA-1
125 # This is the model object created by Catalyst::Model::DBIC from your
126 # schema (you created 'MyAppDB::Role' but as the Catalyst startup
127 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::Role').
128 # NOTE: Omit 'MyApp::Model' to avoid a component lookup issue in Catalyst 5.66
129 role_class: MyAppDB::Role
130 # The name of the field in the 'roles' table that contains the role name
132 # The name of the accessor used to map a role to the users who have this role
133 # See the has_many() in MyAppDB/Role.pm
134 role_rel: map_user_role
135 # The name of the field in the user_role table that references the user
136 user_role_user_field: user_id
139 =head2 Add Role-Specific Logic to the "Book List" Template
141 Open C<root/src/books/list.tt2> in your editor and add the following
142 lines to the bottom of the file:
144 <p>Hello [% Catalyst.user.username %], you have the following roles:</p>
147 [% # Dump list of roles -%]
148 [% FOR role = Catalyst.user.roles %]<li>[% role %]</li>[% END %]
152 [% # Add some simple role-specific logic to template %]
153 [% # Use $c->check_user_roles() to check authz -%]
154 [% IF Catalyst.check_user_roles('user') %]
155 [% # Give normal users a link for 'logout' %]
156 <a href="[% Catalyst.uri_for('/logout') %]">Logout</a>
159 [% # Can also use $c->user->check_roles() to check authz -%]
160 [% IF Catalyst.check_user_roles('admin') %]
161 [% # Give admin users a link for 'create' %]
162 <a href="[% Catalyst.uri_for('form_create') %]">Create</a>
166 This code displays a different combination of links depending on the
167 roles assigned to the user.
169 =head2 Limit C<Books::add> to C<admin> Users
171 C<IF> statements in TT templates simply control the output that is sent
172 to the user's browser; it provides no real enforcement (if users know or
173 guess the appropriate URLs, they are still perfectly free to hit any
174 action within your application). We need to enhance the controller
175 logic to wrap restricted actions with role-validation logic.
177 For example, we might want to restrict the "formless create" action to
178 admin-level users by editing C<lib/MyApp/Controller/Books.pm> and
179 updating C<url_create> to match the following code:
183 Create a book with the supplied title and rating,
184 with manual authorization
188 sub url_create : Local {
189 # In addition to self & context, get the title, rating & author_id args
190 # from the URL. Note that Catalyst automatically puts extra information
191 # after the "/<controller_name>/<action_name/" into @_
192 my ($self, $c, $title, $rating, $author_id) = @_;
194 # Check the user's roles
195 if ($c->check_user_roles('admin')) {
196 # Call create() on the book model object. Pass the table
197 # columns/field values we want to set as hash values
198 my $book = $c->model('MyAppDB::Book')->create({
203 # Add a record to the join table for this book, mapping to
205 $book->add_to_book_authors({author_id => $author_id});
206 # Note: Above is a shortcut for this:
207 # $book->create_related('book_authors', {author_id => $author_id});
209 # Assign the Book object to the stash for display in the view
210 $c->stash->{book} = $book;
212 # This is a hack to disable XSUB processing in Data::Dumper
213 # (it's used in the view). This is a work-around for a bug in
214 # the interaction of some versions or Perl, Data::Dumper & DBIC.
215 # You won't need this if you aren't using Data::Dumper (or if
216 # you are running DBIC 0.06001 or greater), but adding it doesn't
217 # hurt anything either.
218 $Data::Dumper::Useperl = 1;
220 # Set the TT template to use
221 $c->stash->{template} = 'books/create_done.tt2';
223 # Provide very simple feedback to the user
224 $c->response->body('Unauthorized!');
229 To add authorization, we simply wrap the main code of this method in an
230 C<if> statement that calls C<check_user_roles>. If the user does not
231 have the appropriate permissions, they receive an "Unauthorized!"
232 message. Note that we intentionally chose to display the message this
233 way to demonstrate that TT templates will not be used if the response
234 body has already been set. In reality you would probably want to use a
235 technique that maintains the visual continuity of your template layout
236 (for example, using the "status" or "error" message feature added in
239 B<TIP>: If you want to keep your existing C<url_create> method, you can
240 create a new copy and comment out the original by making it look like a
241 Pod comment. For example, put something like C<=begin> before C<sub add
242 : Local {> and C<=end> after the closing C<}>.
244 =head2 Try Out Authentication And Authorization
246 Press C<Ctrl-C> to kill the previous server instance (if it's still
247 running) and restart it:
249 $ script/myapp_server.pl
251 Now trying going to L<http://localhost:3000/books/list> and you should
252 be taken to the login page (you might have to C<Shift+Reload> your
253 browser and/or click the "Logout" link on the book list page). Try
254 logging in with both C<test01> and C<test02> (both use a password
255 of C<mypass>) and notice how the roles information updates at the
256 bottom of the "Book List" page. Also try the C<Logout> link on the
259 Now the "url_create" URL will work if you are already logged in as user
260 C<test01>, but receive an authorization failure if you are logged in as
263 http://localhost:3000/books/url_create/test/1/6
265 while logged in as each user. Use one of the 'Logout' links (or go to
266 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|Catalyst::Plugin::Authorization::ACL>
274 plugin can automate much of the work required to perform role-based
275 authorization in a Catalyst application.
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 admins 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|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!';
389 Then run the Catalyst development server script:
391 $ script/myapp_server.pl
393 Log in as C<test02>. Once at the book list, click the "Create" link to
394 try the C<form_create> action. You should receive a red "Unauthorized!"
395 error message at the top of the list. (Note that in reality you would
396 probably want to place the "Create" link code in
397 C<root/src/books/list.tt2> inside an C<IF> statement that only displays
398 the list to admin-level users.) If you log in as C<test01> you should
399 be able to view the C<form_create> form and add a new book.
401 When you are done, use one of the 'Logout' links (or go to the
402 L<http://localhost:3000/logout> URL directly) when you are done.
407 Kennedy Clark, C<hkclark@gmail.com>
409 Please report any errors, issues or suggestions to the author. The
410 most recent version of the Catlayst Tutorial can be found at
411 L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/Catalyst-Runtime/lib/Catalyst/Manual/Tutorial/>.
413 Copyright 2006, Kennedy Clark, under Creative Commons License
414 (L<http://creativecommons.org/licenses/by-nc-sa/2.5/>).