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:
87 Authentication::Store::DBIC
88 Authentication::Credential::Password
92 Session::Store::FastMmap
93 Session::State::Cookie
97 =head2 Add Config Information for Authorization
99 Edit C<myapp.yml> and update it to match (everything from the
100 "authorization:" line down is new):
106 # Note this first definition would be the same as setting
107 # __PACKAGE__->config->{authentication}->{dbic}->{user_class} = 'MyAppDB::User'
108 # in lib/MyApp.pm (IOW, each hash key becomes a "name:" in the YAML file).
110 # This is the model object created by Catalyst::Model::DBIC from your
111 # schema (you created 'MyAppDB::User' but as the Catalyst startup
112 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::User').
113 # NOTE: Omit 'MyAppDB::Model' to avoid a component lookup issue in Catalyst 5.66
114 user_class: MyAppDB::User
115 # This is the name of the field in your 'users' table that contains the user's name
117 # This is the name of the field in your 'users' table that contains the password
118 password_field: password
119 # Other options can go here for hashed passwords
120 # Enabled hashed passwords
121 password_type: hashed
122 # Use the SHA-1 hashing algorithm
123 password_hash_type: SHA-1
126 # This is the model object created by Catalyst::Model::DBIC from your
127 # schema (you created 'MyAppDB::Role' but as the Catalyst startup
128 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::Role').
129 # NOTE: Omit 'MyAppDB::Model' to avoid a component lookup issue in Catalyst 5.66
130 role_class: MyAppDB::Role
131 # The name of the field in the 'roles' table that contains the role name
133 # The name of the accessor used to map a user to a role
134 # See the has_many() in MyAppDB/User.pm
135 role_rel: map_user_role
136 # The name of the field in the user_role table that references the user
137 user_role_user_field: user_id
140 =head2 Add Role-Specific Logic to the "Book List" Template
142 Open C<root/src/books/list.tt2> in your editor and add the following
143 lines to the bottom of the file:
145 <p>Hello [% Catalyst.user.username %], you have the following roles:</p>
148 [% # Dump list of roles -%]
149 [% FOR role = Catalyst.user.roles %]<li>[% role %]</li>[% END %]
153 [% # Add some simple role-specific logic to template %]
154 [% # Use $c->check_user_roles() to check authz -%]
155 [% IF Catalyst.check_user_roles('user') %]
156 [% # Give normal users a link for 'logout' %]
157 <a href="[% Catalyst.uri_for('/logout') %]">Logout</a>
160 [% # Can also use $c->user->check_roles() to check authz -%]
161 [% IF Catalyst.check_user_roles('admin') %]
162 [% # Give admin users a link for 'create' %]
163 <a href="[% Catalyst.uri_for('form_create') %]">Create</a>
167 This code displays a different combination of links depending on the
168 roles assigned to the user.
170 =head2 Limit C<Books::add> to C<admin> Users
172 C<IF> statements in TT templates simply control the output that is sent
173 to the user's browser; it provides no real enforcement (if users know or
174 guess the appropriate URLs, they are still perfectly free to hit any
175 action within your application). We need to enhance the controller
176 logic to wrap restricted actions with role-validation logic.
178 For example, we might want to restrict the "formless create" action to
179 admin-level users by editing C<lib/MyApp/Controller/Books.pm> and
180 updating C<url_create> to match the following code:
184 Create a book with the supplied title and rating,
185 with manual authorization
189 sub url_create : Local {
190 # In addition to self & context, get the title, rating & author_id args
191 # from the URL. Note that Catalyst automatically puts extra information
192 # after the "/<controller_name>/<action_name/" into @_
193 my ($self, $c, $title, $rating, $author_id) = @_;
195 # Check the user's roles
196 if ($c->check_user_roles('admin')) {
197 # Call create() on the book model object. Pass the table
198 # columns/field values we want to set as hash values
199 my $book = $c->model('MyAppDB::Book')->create({
204 # Add a record to the join table for this book, mapping to
206 $book->add_to_book_authors({author_id => $author_id});
207 # Note: Above is a shortcut for this:
208 # $book->create_related('book_authors', {author_id => $author_id});
210 # Assign the Book object to the stash for display in the view
211 $c->stash->{book} = $book;
213 # This is a hack to disable XSUB processing in Data::Dumper
214 # (it's used in the view). This is a work-around for a bug in
215 # the interaction of some versions or Perl, Data::Dumper & DBIC.
216 # You won't need this if you aren't using Data::Dumper (or if
217 # you are running DBIC 0.06001 or greater), but adding it doesn't
218 # hurt anything either.
219 $Data::Dumper::Useperl = 1;
221 # Set the TT template to use
222 $c->stash->{template} = 'books/create_done.tt2';
224 # Provide very simple feedback to the user
225 $c->response->body('Unauthorized!');
230 To add authorization, we simply wrap the main code of this method in an
231 C<if> statement that calls C<check_user_roles>. If the user does not
232 have the appropriate permissions, they receive an "Unauthorized!"
233 message. Note that we intentionally chose to display the message this
234 way to demonstrate that TT templates will not be used if the response
235 body has already been set. In reality you would probably want to use a
236 technique that maintains the visual continuity of your template layout
237 (for example, using the "status" or "error" message feature added in
240 B<TIP>: If you want to keep your existing C<url_create> method, you can
241 create a new copy and comment out the original by making it look like a
242 Pod comment. For example, put something like C<=begin> before C<sub add
243 : Local {> and C<=end> after the closing C<}>.
245 =head2 Try Out Authentication And Authorization
247 Press C<Ctrl-C> to kill the previous server instance (if it's still
248 running) and restart it:
250 $ script/myapp_server.pl
252 Now trying going to L<http://localhost:3000/books/list> and you should
253 be taken to the login page (you might have to C<Shift+Reload> your
254 browser). Try logging in with both C<test01> and C<test02> (both use a
255 password of C<mypass>) and notice how the roles information updates at
256 the 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
269 =head1 ENABLE ACL-BASED AUTHORIZATION
271 This section takes a brief look at how the
272 L<Catalyst::Plugin::Authorization::ACL> plugin can automate much of the
273 work required to perform role-based authorization in a Catalyst
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 admin 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>
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!';
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.
411 Copyright 2006, Kennedy Clark, under Creative Commons License
412 (L<http://creativecommons.org/licenses/by-nc-sa/2.5/>).