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 co http://dev.catalyst.perl.org/repos/Catalyst/tags/examples/Tutorial/MyApp/5.7/Authorization MyApp
69 =head1 BASIC AUTHORIZATION
71 In this section you learn how to manually configure authorization.
73 =head2 Update Plugins to Include Support for Authorization
75 Edit C<lib/MyApp.pm> and add C<Authorization::Roles> to the list:
85 Authentication::Store::DBIC
86 Authentication::Credential::Password
90 Session::Store::FastMmap
91 Session::State::Cookie
95 =head2 Add Config Information for Authorization
97 Edit C<myapp.yml> and update it to match (everything from the
98 "authorization:" line down is new):
104 # Note this first definition would be the same as setting
105 # __PACKAGE__->config->{authentication}->{dbic}->{user_class} = 'MyAppDB::User'
106 # in lib/MyApp.pm (IOW, each hash key becomes a "name:" in the YAML file).
108 # This is the model object created by Catalyst::Model::DBIC from your
109 # schema (you created 'MyAppDB::User' but as the Catalyst startup
110 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::User').
111 # NOTE: Omit 'MyApp::Model' to avoid a component lookup issue in Catalyst 5.66
112 user_class: MyAppDB::User
113 # This is the name of the field in your 'users' table that contains the user's name
115 # This is the name of the field in your 'users' table that contains the password
116 password_field: password
117 # Other options can go here for hashed passwords
118 # Enabled hashed passwords
119 password_type: hashed
120 # Use the SHA-1 hashing algorithm
121 password_hash_type: SHA-1
124 # This is the model object created by Catalyst::Model::DBIC from your
125 # schema (you created 'MyAppDB::Role' but as the Catalyst startup
126 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::Role').
127 # NOTE: Omit 'MyApp::Model' to avoid a component lookup issue in Catalyst 5.66
128 role_class: MyAppDB::Role
129 # The name of the field in the 'roles' table that contains the role name
131 # The name of the accessor used to map a role to the users who have this role
132 # See the has_many() in MyAppDB/Role.pm
133 role_rel: map_user_role
134 # The name of the field in the user_role table that references the user
135 user_role_user_field: user_id
138 =head2 Add Role-Specific Logic to the "Book List" Template
140 Open C<root/src/books/list.tt2> in your editor and add the following
141 lines to the bottom of the file:
143 <p>Hello [% Catalyst.user.username %], you have the following roles:</p>
146 [% # Dump list of roles -%]
147 [% FOR role = Catalyst.user.roles %]<li>[% role %]</li>[% END %]
151 [% # Add some simple role-specific logic to template %]
152 [% # Use $c->check_user_roles() to check authz -%]
153 [% IF Catalyst.check_user_roles('user') %]
154 [% # Give normal users a link for 'logout' %]
155 <a href="[% Catalyst.uri_for('/logout') %]">Logout</a>
158 [% # Can also use $c->user->check_roles() to check authz -%]
159 [% IF Catalyst.check_user_roles('admin') %]
160 [% # Give admin users a link for 'create' %]
161 <a href="[% Catalyst.uri_for('form_create') %]">Create</a>
165 This code displays a different combination of links depending on the
166 roles assigned to the user.
168 =head2 Limit C<Books::add> to C<admin> Users
170 C<IF> statements in TT templates simply control the output that is sent
171 to the user's browser; it provides no real enforcement (if users know or
172 guess the appropriate URLs, they are still perfectly free to hit any
173 action within your application). We need to enhance the controller
174 logic to wrap restricted actions with role-validation logic.
176 For example, we might want to restrict the "formless create" action to
177 admin-level users by editing C<lib/MyApp/Controller/Books.pm> and
178 updating C<url_create> to match the following code:
182 Create a book with the supplied title and rating,
183 with manual authorization
187 sub url_create : Local {
188 # In addition to self & context, get the title, rating & author_id args
189 # from the URL. Note that Catalyst automatically puts extra information
190 # after the "/<controller_name>/<action_name/" into @_
191 my ($self, $c, $title, $rating, $author_id) = @_;
193 # Check the user's roles
194 if ($c->check_user_roles('admin')) {
195 # Call create() on the book model object. Pass the table
196 # columns/field values we want to set as hash values
197 my $book = $c->model('MyAppDB::Book')->create({
202 # Add a record to the join table for this book, mapping to
204 $book->add_to_book_authors({author_id => $author_id});
205 # Note: Above is a shortcut for this:
206 # $book->create_related('book_authors', {author_id => $author_id});
208 # Assign the Book object to the stash for display in the view
209 $c->stash->{book} = $book;
211 # This is a hack to disable XSUB processing in Data::Dumper
212 # (it's used in the view). This is a work-around for a bug in
213 # the interaction of some versions or Perl, Data::Dumper & DBIC.
214 # You won't need this if you aren't using Data::Dumper (or if
215 # you are running DBIC 0.06001 or greater), but adding it doesn't
216 # hurt anything either.
217 $Data::Dumper::Useperl = 1;
219 # Set the TT template to use
220 $c->stash->{template} = 'books/create_done.tt2';
222 # Provide very simple feedback to the user
223 $c->response->body('Unauthorized!');
228 To add authorization, we simply wrap the main code of this method in an
229 C<if> statement that calls C<check_user_roles>. If the user does not
230 have the appropriate permissions, they receive an "Unauthorized!"
231 message. Note that we intentionally chose to display the message this
232 way to demonstrate that TT templates will not be used if the response
233 body has already been set. In reality you would probably want to use a
234 technique that maintains the visual continuity of your template layout
235 (for example, using the "status" or "error" message feature added in
238 B<TIP>: If you want to keep your existing C<url_create> method, you can
239 create a new copy and comment out the original by making it look like a
240 Pod comment. For example, put something like C<=begin> before C<sub add
241 : Local {> and C<=end> after the closing C<}>.
243 =head2 Try Out Authentication And Authorization
245 Press C<Ctrl-C> to kill the previous server instance (if it's still
246 running) and restart it:
248 $ script/myapp_server.pl
250 Now trying going to L<http://localhost:3000/books/list> and you should
251 be taken to the login page (you might have to C<Shift+Reload> your
252 browser and/or click the "Logout" link on the book list page). Try
253 logging in with both C<test01> and C<test02> (both use a password
254 of C<mypass>) and notice how the roles information updates at the
255 bottom of the "Book List" page. Also try the C<Logout> link on the
258 Now the "url_create" URL will work if you are already logged in as user
259 C<test01>, but receive an authorization failure if you are logged in as
262 http://localhost:3000/books/url_create/test/1/6
264 while logged in as each user. Use one of the 'Logout' links (or go to
265 L<http://localhost:3000/logout> in you browser directly) when you are
269 =head1 ENABLE ACL-BASED AUTHORIZATION
271 This section takes a brief look at how the
272 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
273 plugin can automate much of the work required to perform role-based
274 authorization in a Catalyst application.
276 =head2 Add the C<Catalyst::Plugin::Authorization::ACL> Plugin
278 Open C<lib/MyApp.pm> in your editor and add the following plugin to the
279 C<use Catalyst> statement:
283 Note that the remaining C<use Catalyst> plugins from earlier sections
284 are not shown here, but they should still be included.
286 =head2 Add ACL Rules to the Application Class
288 Open C<lib/MyApp.pm> in your editor and add the following B<BELOW> the
289 C<__PACKAGE__-E<gt>setup;> statement:
291 # Authorization::ACL Rules
292 __PACKAGE__->deny_access_unless(
293 "/books/form_create",
296 __PACKAGE__->deny_access_unless(
297 "/books/form_create_do",
300 __PACKAGE__->deny_access_unless(
305 Each of the three statements above comprises an ACL plugin "rule". The
306 first two rules only allow admin-level users to create new books using
307 the form (both the form itself and the data submission logic are
308 protected). The third statement allows both users and admins to delete
309 books. The C</books/url_create> action will continue to be protected by
310 the "manually configured" authorization created earlier in this part of
313 The ACL plugin permits you to apply allow/deny logic in a variety of
314 ways. The following provides a basic overview of the capabilities:
320 The ACL plugin only operates on the Catalyst "private namespace". You
321 are using the private namespace when you use C<Local> actions. C<Path>,
322 C<Regex>, and C<Global> allow you to specify actions where the path and
323 the namespace differ -- the ACL plugin will not work in these cases.
327 Each rule is expressed in a separate
328 C<__PACKAGE__-E<gt>deny_access_unless()> or
329 C<__PACKAGE__-E<gt>allow_access_if()> line (there are several other
330 methods that can be used for more complex policies, see the C<METHODS>
332 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
333 documentation for more details).
337 Each rule can contain multiple roles but only a single path.
341 The rules are tried in order (with the "most specific" rules tested
342 first), and processing stops at the first "match" where an allow or deny
343 is specified. Rules "fall through" if there is not a "match" (where a
344 "match" means the user has the specified role). If a "match" is found,
345 then processing stops there and the appropriate allow/deny action is
350 If none of the rules match, then access is allowed.
354 The rules currently need to be specific in the application class
355 C<lib\MyApp.pm> B<after> the C<__PACKAGE__-E<gt>setup;> line.
359 =head2 Add a Method to Handle Access Violations
362 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
363 throws an exception when authorization fails. This will take the user
364 to the Catalyst debug screen, or a "Please come back later" message if
365 you are not using the C<-Debug> flag. This step uses the
366 C<access_denied> method in order to provide more appropriate feedback to
369 Open C<lib/MyApp/Controller/Books.pm> in your editor and add the
374 Handle Catalyst::Plugin::Authorization::ACL access denied exceptions
378 sub access_denied : Private {
381 # Set the error message
382 $c->stash->{error_msg} = 'Unauthorized!';
388 Then run the Catalyst development server script:
390 $ script/myapp_server.pl
392 Log in as C<test02>. Once at the book list, click the "Create" link to
393 try the C<form_create> action. You should receive a red "Unauthorized!"
394 error message at the top of the list. (Note that in reality you would
395 probably want to place the "Create" link code in
396 C<root/src/books/list.tt2> inside an C<IF> statement that only displays
397 the list to admin-level users.) If you log in as C<test01> you should
398 be able to view the C<form_create> form and add a new book.
400 When you are done, use one of the 'Logout' links (or go to the
401 L<http://localhost:3000/logout> URL directly) when you are done.
406 Kennedy Clark, C<hkclark@gmail.com>
408 Please report any errors, issues or suggestions to the author. The
409 most recent version of the Catalyst Tutorial can be found at
410 L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/Catalyst-Runtime/lib/Catalyst/Manual/Tutorial/>.
412 Copyright 2006, Kennedy Clark, under Creative Commons License
413 (L<http://creativecommons.org/licenses/by-nc-sa/2.5/>).