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<Appendicies|Catalyst::Manual::Tutorial::Appendicies>
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.
71 =head1 BASIC AUTHORIZATION
73 In this section you learn how to manually configure authorization.
76 =head2 Update Plugins to Include Support Authorization
78 Edit C<lib/MyApp.pm> and add C<Authorization::Roles> to the list:
90 Authentication::Store::DBIC
91 Authentication::Credential::Password
95 Session::Store::FastMmap
96 Session::State::Cookie
100 =head2 Add Config Information for Authorization
102 Edit C<myapp.yml> and update it to match (everything from the "authorization:" line down is new):
108 # Note this first definition would be the same as setting
109 # __PACKAGE__->config->{authentication}->{dbic}->{user_class} = 'MyAppDB::User'
110 # in lib/MyApp.pm (IOW, each hash key becomes a "name:" in the YAML file).
112 # This is the model object created by Catalyst::Model::DBIC from your
113 # schema (you created 'MyAppDB::User' but as the Catalyst startup
114 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::User').
115 # NOTE: Omit 'MyAppDB::Model' to avoid a component lookup issue in Catalyst 5.66
116 user_class: MyAppDB::User
117 # This is the name of the field in your 'users' table that contains the user's name
119 # This is the name of the field in your 'users' table that contains the password
120 password_field: password
121 # Other options can go here for hashed passwords
122 # Enabled hashed passwords
123 password_type: hashed
124 # Use the SHA-1 hashing algorithm
125 password_hash_type: SHA-1
128 # This is the model object created by Catalyst::Model::DBIC from your
129 # schema (you created 'MyAppDB::Role' but as the Catalyst startup
130 # debug messages show, it was loaded as 'MyApp::Model::MyAppDB::Role').
131 # NOTE: Omit 'MyAppDB::Model' to avoid a component lookup issue in Catalyst 5.66
132 role_class: MyAppDB::Role
133 # The name of the field in the 'roles' table that contains the role name
135 # The name of the accessor used to map a user to a role
136 # See the has_many() in MyAppDB/User.pm
137 role_rel: map_user_role
138 # The name of the field in the user_role table that references the user
139 user_role_user_field: user_id
142 =head2 Add Role-Specific Logic to the "Book List" Template
144 Open C<root/src/books/list.tt2> in your editor and add the following
145 lines to the bottom of the file:
147 <p>Hello [% Catalyst.user.username %], you have the following roles:</p>
150 [% # Dump list of roles -%]
151 [% FOR role = Catalyst.user.roles %]<li>[% role %]</li>[% END %]
155 [% # Add some simple role-specific logic to template %]
156 [% # Use $c->check_user_roles() to check authz -%]
157 [% IF Catalyst.check_user_roles('user') %]
158 [% # Give normal users a link for 'logout' %]
159 <a href="[% Catalyst.uri_for('/logout') %]">Logout</a>
162 [% # Can also use $c->user->check_roles() to check authz -%]
163 [% IF Catalyst.check_user_roles('admin') %]
164 [% # Give admin users a link for 'create' %]
165 <a href="[% Catalyst.uri_for('form_create') %]">Create</a>
169 This code displays a different combination of links depending on the roles assigned to the user..
172 =head2 Limit C<Books::add> to C<admin> Users
174 C<IF> statements in TT templates simply control the output that is sent
175 to the user's browser; it provides no real enforcement (if users know or
176 guess the appropriate URLs, they are still perfectly free to hit any
177 action within your application). We need to enhance the controller
178 logic to wrap restricted actions with role validation logic.
180 For example, we might want to restrict the "formless create" action to
181 admin-level users by editing C<lib/MyApp/Controller/Books.pm> and
182 updating C<url_create> to match the following code:
186 Create a book with the supplied title, and rating
187 with manual authorization
191 sub url_create : Local {
192 # In addition to self & context, get the title, rating & author_id args
193 # from the URL. Note that Catalyst automatically puts extra information
194 # after the "/<controller_name>/<action_name/" into @_
195 my ($self, $c, $title, $rating, $author_id) = @_;
197 # Check the user's roles
198 if ($c->check_user_roles('admin')) {
199 # Call create() on the book model object. Pass the table
200 # columns/field values we want to set as hash values
201 my $book = $c->model('MyAppDB::Book')->create({
206 # Add a record to the join table for this book, mapping to
208 $book->add_to_book_authors({author_id => $author_id});
209 # Note: Above is a shortcut for this:
210 # $book->create_related('book_authors', {author_id => $author_id});
212 # Assign the Book object to the stash for display in the view
213 $c->stash->{book} = $book;
215 # This is a hack to disable XSUB processing in Data::Dumper
216 # (it's used in the view). This is a work-around for a bug in
217 # the interaction of some versions or Perl, Data::Dumper & DBIC.
218 # You won't need this if you aren't using Data::Dumper (or if
219 # you are running DBIC 0.06001 or greater), but adding it doesn't
220 # hurt anything either.
221 $Data::Dumper::Useperl = 1;
223 # Set the TT template to use
224 $c->stash->{template} = 'books/create_done.tt2';
226 # Provide very simple feedback to the user
227 $c->response->body('Unauthorized!');
232 To add authorization, we simply write the main code of this method in an
233 C<if> statement that calls C<check_user_roles>. If the user does not
234 have the appropriate permissions, they receive an "Unauthorized!"
235 message. Note that we intentionally chose to display the message this
236 way to demonstrate that TT templates will not be used if the response
237 body has already been set. In reality you would probably want to use a
238 technique that maintains the visual continuity of your template layout
239 (for example, using the "status" or "error" message feature added in
242 B<TIP>: If you want to keep your existing C<url_create> method, you can
243 create a new copy and comment out the original by making it look like a
244 Pod comment. For example, put something like C<=begin> before C<sub add
245 : Local {> and C<=end> after the closing C<}>.
248 =head2 Try Out Authentication And Authorization
250 Press C<Ctrl-C> to kill the previous server instance (if it's still running) and restart it:
252 $ script/myapp_server.pl
254 Now trying going to L<http://localhost:3000/books/list> and you should
255 be taken to the login page (you might have to C<Shift+Reload> your
256 browser). Try logging in with both C<test01> and C<test02> (both use a
257 password of C<mypass>) and notice how the roles information updates at
258 the bottom of the "Book List" page. Also try the C<Logout> link on the
261 Now the "url_create" URL will work if you are already logged in as user
262 C<test01>, but receive an authorization failure if you are logged in as
265 http://localhost:3000/books/url_create/test/1/6
267 while logged in as each user. Use one of the 'Logout' links (or go to
268 L<http://localhost:3000/logout> in you browser directly) when you are
273 =head1 ENABLE ACL-BASED AUTHORIZATION
275 This section takes a brief look at how the
276 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
277 can automate much of the work required to perform role-based
278 authorization in a Catalyst application.
281 =head2 Add the C<Catalyst::Plugin::Authorization::ACL> Plugin
283 Open C<lib/MyApp.pm> in your editor and add the following plugin to the
284 C<use Catalyst> statement:
288 Note that the remaining C<use Catalyst> plugins from earlier sections
289 are not shown here, but they should still be included.
292 =head2 Add ACL Rules to the Application Class
294 Open C<lib/MyApp.pm> in your editor and add the following B<BELOW> the
295 C<__PACKAGE__-E<gt>setup;> statement:
297 # Authorization::ACL Rules
298 __PACKAGE__->deny_access_unless(
299 "/books/form_create",
302 __PACKAGE__->deny_access_unless(
303 "/books/form_create_do",
306 __PACKAGE__->deny_access_unless(
311 Each of the three statements above comprises an ACL plugin "rule". The
312 first two rules only allow admin-level users to create new books using
313 the form (both the form itself and the data submission logic are
314 protected). The third statement allows both users and admin to delete
315 books. The C</books/url_create> action will continue to be protected by
316 the "manually configured" authorization created earlier in this part of
319 The ACL plugin permits you to apply allow/deny logic in a variety of
320 ways. The following provides a basic overview of the capabilities:
326 The ACL plugin only operates on the Catalyst "private namespace". You
327 are using the private namespace when you use C<Local> actions. C<Path>,
328 C<Regex>, and C<Global> allow you to specify actions where the path and
329 the namespace differ -- the ACL plugin will not work in these cases.
333 Each rule is expressed in a separate
334 C<__PACKAGE__-E<gt>deny_access_unless()> or
335 C<__PACKAGE__-E<gt>allow_access_if()> line (there are several other
336 methods that can be used for more complex policies, see the C<METHODS>
338 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
339 documentation for more details).
343 Each rule can contain multiple roles but only a single path.
347 The rules are tried in order (with the "most specific" rules tested
348 first), and processing stops at the first "match" where an allow or deny
349 is specified. Rules "fall through" if there is not a "match" (where a
350 "match" means the user has the specified role). If a "match" is found,
351 then processing stops there and the appropriate allow/deny action is
356 If none of the rules match, then access is allowed.
360 The rules currently need to be specific in the application class
361 C<lib\MyApp.pm> B<after> the C<__PACKAGE__-E<gt>setup;> line.
366 =head2 Add a Method to Handle Access Violations
369 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
370 throws an exception when authorization fails. This will take the user
371 to the Catalyst debug screen, or a "Please come back later" message if
372 you are not using the C<-Debug> flag. This step uses the
373 C<access_denied> method in order to provide more appropriate feedback to
376 Open C<lib/MyApp/Controller/Books.pm> in your editor and add the
381 Handle Catalyst::Plugin::Authorization::ACL access denied exceptions
385 sub access_denied : Private {
388 # Set the error message
389 $c->stash->{error_msg} = 'Unauthorized!';
396 Then run the Catalyst development server script:
398 $ script/myapp_server.pl
400 Log in as C<test02>. Once at the book list, click the "Create" link to
401 try the C<form_create> action. You should receive a red "Unauthorized!"
402 error message at the top of the list. (Note that in reality you would
403 probably want to place the "Create" link code in
404 C<root/src/books/list.tt2> inside an C<IF> statement that only displays
405 the list to admin-level users.) If you log in as C<test01> you should
406 be able to view the C<form_create> form and add a new book.
408 When you are done, use one of the 'Logout' links (or go to the
409 L<http://localhost:3000/logout> URL directly) when you are done.
415 Kennedy Clark, C<hkclark@gmail.com>
417 Please report any errors, issues or suggestions to the author.
419 Copyright 2006, Kennedy Clark, under Creative Commons License (L<http://creativecommons.org/licenses/by-nc-sa/2.5/>).