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 You can checkout the source code for this example from the catalyst
63 subversion repository as per the instructions in
64 L<Catalyst::Manual::Tutorial::Intro>
66 =head1 BASIC AUTHORIZATION
68 In this section you learn how to manually configure authorization.
70 =head2 Update Plugins to Include Support for Authorization
72 Edit C<lib/MyApp.pm> and add C<Authorization::Roles> to the list:
82 Authentication::Store::DBIC
83 Authentication::Credential::Password
87 Session::Store::FastMmap
88 Session::State::Cookie
92 =head2 Add Config Information for Authorization
94 Edit C<myapp.yml> and update it to match (everything from the
95 "authorization:" line down is new):
101 # Note this first definition would be the same as setting
102 # __PACKAGE__->config->{authentication}->{dbic}->{user_class} = 'MyAppDB::User'
103 # in lib/MyApp.pm (IOW, each hash key becomes a "name:" in the YAML file).
105 # This is the model object created by Catalyst::Model::DBIC from your
106 # schema (you created 'MyAppDB::User' but as the Catalyst startup
107 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::User').
108 # NOTE: Omit 'MyApp::Model' here just as you would when using
109 # '$c->model("MyAppDB::User)'
110 user_class: MyAppDB::User
111 # This is the name of the field in your 'users' table that contains the user's name
113 # This is the name of the field in your 'users' table that contains the password
114 password_field: password
115 # Other options can go here for hashed passwords
116 # Enabled hashed passwords
117 password_type: hashed
118 # Use the SHA-1 hashing algorithm
119 password_hash_type: SHA-1
122 # This is the model object created by Catalyst::Model::DBIC from your
123 # schema (you created 'MyAppDB::Role' but as the Catalyst startup
124 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::Role').
125 # NOTE: Omit 'MyApp::Model' here just as you would when using
126 # '$c->model("MyAppDB::User)'
127 role_class: MyAppDB::Role
128 # The name of the field in the 'roles' table that contains the role name
130 # The name of the accessor used to map a role to the users who have this role
131 # See the has_many() in MyAppDB/Role.pm
132 role_rel: map_user_role
133 # The name of the field in the user_role table that references the user
134 user_role_user_field: user_id
137 =head2 Add Role-Specific Logic to the "Book List" Template
139 Open C<root/src/books/list.tt2> in your editor and add the following
140 lines to the bottom of the file:
142 <p>Hello [% Catalyst.user.username %], you have the following roles:</p>
145 [% # Dump list of roles -%]
146 [% FOR role = Catalyst.user.roles %]<li>[% role %]</li>[% END %]
150 [% # Add some simple role-specific logic to template %]
151 [% # Use $c->check_user_roles() to check authz -%]
152 [% IF Catalyst.check_user_roles('user') %]
153 [% # Give normal users a link for 'logout' %]
154 <a href="[% Catalyst.uri_for('/logout') %]">Logout</a>
157 [% # Can also use $c->user->check_roles() to check authz -%]
158 [% IF Catalyst.check_user_roles('admin') %]
159 [% # Give admin users a link for 'create' %]
160 <a href="[% Catalyst.uri_for('form_create') %]">Create</a>
164 This code displays a different combination of links depending on the
165 roles assigned to the user.
167 =head2 Limit C<Books::add> to C<admin> Users
169 C<IF> statements in TT templates simply control the output that is sent
170 to the user's browser; it provides no real enforcement (if users know or
171 guess the appropriate URLs, they are still perfectly free to hit any
172 action within your application). We need to enhance the controller
173 logic to wrap restricted actions with role-validation logic.
175 For example, we might want to restrict the "formless create" action to
176 admin-level users by editing C<lib/MyApp/Controller/Books.pm> and
177 updating C<url_create> to match the following code:
181 Create a book with the supplied title and rating,
182 with manual authorization
186 sub url_create : Local {
187 # In addition to self & context, get the title, rating & author_id args
188 # from the URL. Note that Catalyst automatically puts extra information
189 # after the "/<controller_name>/<action_name/" into @_
190 my ($self, $c, $title, $rating, $author_id) = @_;
192 # Check the user's roles
193 if ($c->check_user_roles('admin')) {
194 # Call create() on the book model object. Pass the table
195 # columns/field values we want to set as hash values
196 my $book = $c->model('MyAppDB::Book')->create({
201 # Add a record to the join table for this book, mapping to
203 $book->add_to_book_authors({author_id => $author_id});
204 # Note: Above is a shortcut for this:
205 # $book->create_related('book_authors', {author_id => $author_id});
207 # Assign the Book object to the stash for display in the view
208 $c->stash->{book} = $book;
210 # This is a hack to disable XSUB processing in Data::Dumper
211 # (it's used in the view). This is a work-around for a bug in
212 # the interaction of some versions or Perl, Data::Dumper & DBIC.
213 # You won't need this if you aren't using Data::Dumper (or if
214 # you are running DBIC 0.06001 or greater), but adding it doesn't
215 # hurt anything either.
216 $Data::Dumper::Useperl = 1;
218 # Set the TT template to use
219 $c->stash->{template} = 'books/create_done.tt2';
221 # Provide very simple feedback to the user
222 $c->response->body('Unauthorized!');
227 To add authorization, we simply wrap the main code of this method in an
228 C<if> statement that calls C<check_user_roles>. If the user does not
229 have the appropriate permissions, they receive an "Unauthorized!"
230 message. Note that we intentionally chose to display the message this
231 way to demonstrate that TT templates will not be used if the response
232 body has already been set. In reality you would probably want to use a
233 technique that maintains the visual continuity of your template layout
234 (for example, using the "status" or "error" message feature added in
237 B<TIP>: If you want to keep your existing C<url_create> method, you can
238 create a new copy and comment out the original by making it look like a
239 Pod comment. For example, put something like C<=begin> before C<sub add
240 : Local {> and C<=end> after the closing C<}>.
242 =head2 Try Out Authentication And Authorization
244 Press C<Ctrl-C> to kill the previous server instance (if it's still
245 running) and restart it:
247 $ script/myapp_server.pl
249 Now trying going to L<http://localhost:3000/books/list> and you should
250 be taken to the login page (you might have to C<Shift+Reload> your
251 browser and/or click the "Logout" link on the book list page). Try
252 logging in with both C<test01> and C<test02> (both use a password
253 of C<mypass>) and notice how the roles information updates at the
254 bottom of the "Book List" page. Also try the C<Logout> link on the
257 Now the "url_create" URL will work if you are already logged in as user
258 C<test01>, but receive an authorization failure if you are logged in as
261 http://localhost:3000/books/url_create/test/1/6
263 while logged in as each user. Use one of the 'Logout' links (or go to
264 L<http://localhost:3000/logout> in you browser directly) when you are
268 =head1 ENABLE ACL-BASED AUTHORIZATION
270 This section takes a brief look at how the
271 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
272 plugin can automate much of the work required to perform role-based
273 authorization in a Catalyst application.
275 =head2 Add the C<Catalyst::Plugin::Authorization::ACL> Plugin
277 Open C<lib/MyApp.pm> in your editor and add the following plugin to the
278 C<use Catalyst> statement:
282 Note that the remaining C<use Catalyst> plugins from earlier sections
283 are not shown here, but they should still be included.
285 =head2 Add ACL Rules to the Application Class
287 Open C<lib/MyApp.pm> in your editor and add the following B<BELOW> the
288 C<__PACKAGE__-E<gt>setup;> statement:
290 # Authorization::ACL Rules
291 __PACKAGE__->deny_access_unless(
292 "/books/form_create",
295 __PACKAGE__->deny_access_unless(
296 "/books/form_create_do",
299 __PACKAGE__->deny_access_unless(
304 Each of the three statements above comprises an ACL plugin "rule". The
305 first two rules only allow admin-level users to create new books using
306 the form (both the form itself and the data submission logic are
307 protected). The third statement allows both users and admins to delete
308 books. The C</books/url_create> action will continue to be protected by
309 the "manually configured" authorization created earlier in this part of
312 The ACL plugin permits you to apply allow/deny logic in a variety of
313 ways. The following provides a basic overview of the capabilities:
319 The ACL plugin only operates on the Catalyst "private namespace". You
320 are using the private namespace when you use C<Local> actions. C<Path>,
321 C<Regex>, and C<Global> allow you to specify actions where the path and
322 the namespace differ -- the ACL plugin will not work in these cases.
326 Each rule is expressed in a separate
327 C<__PACKAGE__-E<gt>deny_access_unless()> or
328 C<__PACKAGE__-E<gt>allow_access_if()> line (there are several other
329 methods that can be used for more complex policies, see the C<METHODS>
331 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
332 documentation for more details).
336 Each rule can contain multiple roles but only a single path.
340 The rules are tried in order (with the "most specific" rules tested
341 first), and processing stops at the first "match" where an allow or deny
342 is specified. Rules "fall through" if there is not a "match" (where a
343 "match" means the user has the specified role). If a "match" is found,
344 then processing stops there and the appropriate allow/deny action is
349 If none of the rules match, then access is allowed.
353 The rules currently need to be specific in the application class
354 C<lib\MyApp.pm> B<after> the C<__PACKAGE__-E<gt>setup;> line.
358 =head2 Add a Method to Handle Access Violations
361 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
362 throws an exception when authorization fails. This will take the user
363 to the Catalyst debug screen, or a "Please come back later" message if
364 you are not using the C<-Debug> flag. This step uses the
365 C<access_denied> method in order to provide more appropriate feedback to
368 Open C<lib/MyApp/Controller/Books.pm> in your editor and add the
373 Handle Catalyst::Plugin::Authorization::ACL access denied exceptions
377 sub access_denied : Private {
380 # Set the error message
381 $c->stash->{error_msg} = 'Unauthorized!';
387 Then run the Catalyst development server script:
389 $ script/myapp_server.pl
391 Log in as C<test02>. Once at the book list, click the "Create" link to
392 try the C<form_create> action. You should receive a red "Unauthorized!"
393 error message at the top of the list. (Note that in reality you would
394 probably want to place the "Create" link code in
395 C<root/src/books/list.tt2> inside an C<IF> statement that only displays
396 the list to admin-level users.) If you log in as C<test01> you should
397 be able to view the C<form_create> form and add a new book.
399 When you are done, use one of the 'Logout' links (or go to the
400 L<http://localhost:3000/logout> URL directly) when you are done.
405 Kennedy Clark, C<hkclark@gmail.com>
407 Please report any errors, issues or suggestions to the author. The
408 most recent version of the Catalyst Tutorial can be found at
409 L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/Catalyst-Manual/lib/Catalyst/Manual/Tutorial/>.
411 Copyright 2006, Kennedy Clark, under Creative Commons License
412 (L<http://creativecommons.org/licenses/by-nc-sa/2.5/>).