3 Catalyst::Manual::Tutorial::Authorization - Catalyst Tutorial - Part 6: Authorization
8 This is B<Part 6 of 10> 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<More Catalyst Basics|Catalyst::Manual::Tutorial::MoreCatalystBasics>
28 L<Basic CRUD|Catalyst::Manual::Tutorial::BasicCRUD>
32 L<Authentication|Catalyst::Manual::Tutorial::Authentication>
40 L<Debugging|Catalyst::Manual::Tutorial::Debugging>
44 L<Testing|Catalyst::Manual::Tutorial::Testing>
48 L<Advanced CRUD|Catalyst::Manual::Tutorial::AdvancedCRUD>
52 L<Appendices|Catalyst::Manual::Tutorial::Appendices>
59 This part of the tutorial adds role-based authorization to the existing
60 authentication implemented in Part 5. It provides simple examples of
61 how to use roles in both TT templates and controller actions. The first
62 half looks at manually configured authorization. The second half looks
63 at how the ACL authorization plugin can simplify your code.
65 You can checkout the source code for this example from the catalyst
66 subversion repository as per the instructions in
67 L<Catalyst::Manual::Tutorial::Intro|Catalyst::Manual::Tutorial::Intro>.
70 =head1 BASIC AUTHORIZATION
72 In this section you learn how to manually configure authorization.
75 =head2 Update Plugins to Include Support for Authorization
77 Edit C<lib/MyApp.pm> and add C<Authorization::Roles> to the list:
79 __PACKAGE__->setup(qw/
90 Session::Store::FastMmap
91 Session::State::Cookie
94 B<Note:> As discussed in MoreCatalystBasics, different versions of
95 C<Catalyst::Devel> have used a variety of methods to load the plugins.
96 You can put the plugins in the C<use Catalyst> statement if you prefer.
99 =head2 Add Config Information for Authorization
101 Edit C<myapp.conf> and update it to match the following (the
102 C<role_relation> and C<role_field> definitions are new):
104 # rename this file to MyApp.yml and put a : in front of "name" if
105 # you want to use yaml like in old versions of Catalyst
112 # Note this first definition would be the same as setting
113 # __PACKAGE__->config->{authentication}->{realms}->{dbic}
114 # ->{credential} = 'Password' in lib/MyApp.pm
116 # Specify that we are going to do password-based auth
118 # This is the name of the field in the users table with the
119 # password stored in it
120 password_field password
121 # Switch to more secure hashed passwords
123 # Use the SHA-1 hashing algorithm
124 password_hash_type SHA-1
127 # Use DBIC to retrieve username, password & role information
129 # This is the model object created by Catalyst::Model::DBIC
130 # from your schema (you created 'MyApp::Schema::User' but as
131 # the Catalyst startup debug messages show, it was loaded as
132 # 'MyApp::Model::DB::Users').
133 # NOTE: Omit 'MyApp::Model' here just as you would when using
134 # '$c->model("DB::Users)'
136 # This is the name of a many_to_many relation in the users
137 # object that points to the roles for that user
139 # This is the name of field in the roles table that contains
140 # the role information
148 =head2 Add Role-Specific Logic to the "Book List" Template
150 Open C<root/src/books/list.tt2> in your editor and add the following
151 lines to the bottom of the file:
153 <p>Hello [% c.user.username %], you have the following roles:</p>
156 [% # Dump list of roles -%]
157 [% FOR role = c.user.roles %]<li>[% role %]</li>[% END %]
161 [% # Add some simple role-specific logic to template %]
162 [% # Use $c->check_user_roles() to check authz -%]
163 [% IF c.check_user_roles('user') %]
164 [% # Give normal users a link for 'logout' %]
165 <a href="[% c.uri_for('/logout') %]">Logout</a>
168 [% # Can also use $c->user->check_roles() to check authz -%]
169 [% IF c.check_user_roles('admin') %]
170 [% # Give admin users a link for 'create' %]
171 <a href="[% c.uri_for('form_create') %]">Create</a>
175 This code displays a different combination of links depending on the
176 roles assigned to the user.
179 =head2 Limit C<Books::add> to C<admin> Users
181 C<IF> statements in TT templates simply control the output that is sent
182 to the user's browser; it provides no real enforcement (if users know or
183 guess the appropriate URLs, they are still perfectly free to hit any
184 action within your application). We need to enhance the controller
185 logic to wrap restricted actions with role-validation logic.
187 For example, we might want to restrict the "formless create" action to
188 admin-level users by editing C<lib/MyApp/Controller/Books.pm> and
189 updating C<url_create> to match the following code:
193 Create a book with the supplied title and rating,
194 with manual authorization
198 sub url_create : Local {
199 # In addition to self & context, get the title, rating & author_id args
200 # from the URL. Note that Catalyst automatically puts extra information
201 # after the "/<controller_name>/<action_name/" into @_
202 my ($self, $c, $title, $rating, $author_id) = @_;
204 # Check the user's roles
205 if ($c->check_user_roles('admin')) {
206 # Call create() on the book model object. Pass the table
207 # columns/field values we want to set as hash values
208 my $book = $c->model('DB::Books')->create({
213 # Add a record to the join table for this book, mapping to
215 $book->add_to_book_authors({author_id => $author_id});
216 # Note: Above is a shortcut for this:
217 # $book->create_related('book_authors', {author_id => $author_id});
219 # Assign the Book object to the stash for display in the view
220 $c->stash->{book} = $book;
222 # This is a hack to disable XSUB processing in Data::Dumper
223 # (it's used in the view). This is a work-around for a bug in
224 # the interaction of some versions or Perl, Data::Dumper & DBIC.
225 # You won't need this if you aren't using Data::Dumper (or if
226 # you are running DBIC 0.06001 or greater), but adding it doesn't
227 # hurt anything either.
228 $Data::Dumper::Useperl = 1;
230 # Set the TT template to use
231 $c->stash->{template} = 'books/create_done.tt2';
233 # Provide very simple feedback to the user
234 $c->response->body('Unauthorized!');
239 To add authorization, we simply wrap the main code of this method in an
240 C<if> statement that calls C<check_user_roles>. If the user does not
241 have the appropriate permissions, they receive an "Unauthorized!"
242 message. Note that we intentionally chose to display the message this
243 way to demonstrate that TT templates will not be used if the response
244 body has already been set. In reality you would probably want to use a
245 technique that maintains the visual continuity of your template layout
246 (for example, using the "status" or "error" message feature added in
249 B<TIP>: If you want to keep your existing C<url_create> method, you can
250 create a new copy and comment out the original by making it look like a
251 Pod comment. For example, put something like C<=begin> before C<sub add
252 : Local {> and C<=end> after the closing C<}>.
255 =head2 Try Out Authentication And Authorization
257 Press C<Ctrl-C> to kill the previous server instance (if it's still
258 running) and restart it:
260 $ script/myapp_server.pl
262 Now trying going to L<http://localhost:3000/books/list> and you should
263 be taken to the login page (you might have to C<Shift+Reload> or
264 C<Ctrl+Reload> your browser and/or click the "Logout" link on the book
265 list page). Try logging in with both C<test01> and C<test02> (both
266 use a password of C<mypass>) and notice how the roles information
267 updates at the bottom of the "Book List" page. Also try the C<Logout>
268 link on the book list page.
270 Now the "url_create" URL will work if you are already logged in as user
271 C<test01>, but receive an authorization failure if you are logged in as
274 http://localhost:3000/books/url_create/test/1/6
276 while logged in as each user. Use one of the 'Logout' links (or go to
277 L<http://localhost:3000/logout> in your browser directly) when you are
281 =head1 ENABLE ACL-BASED AUTHORIZATION
283 This section takes a brief look at how the
284 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
285 plugin can automate much of the work required to perform role-based
286 authorization in a Catalyst application.
289 =head2 Add the C<Catalyst::Plugin::Authorization::ACL> Plugin
291 Open C<lib/MyApp.pm> in your editor and add the following plugin to the
292 C<__PACKAGE__-E<gt>setup> statement:
296 Note that the remaining C<use Catalyst> plugins from earlier sections
297 are not shown here, but they should still be included.
300 =head2 Add ACL Rules to the Application Class
302 Open C<lib/MyApp.pm> in your editor and add the following B<BELOW> the
303 C<__PACKAGE__-E<gt>setup> statement:
305 # Authorization::ACL Rules
306 __PACKAGE__->deny_access_unless(
307 "/books/form_create",
310 __PACKAGE__->deny_access_unless(
311 "/books/form_create_do",
314 __PACKAGE__->deny_access_unless(
319 Each of the three statements above comprises an ACL plugin "rule". The
320 first two rules only allow admin-level users to create new books using
321 the form (both the form itself and the data submission logic are
322 protected). The third statement allows both users and admins to delete
323 books. The C</books/url_create> action will continue to be protected by
324 the "manually configured" authorization created earlier in this part of
327 The ACL plugin permits you to apply allow/deny logic in a variety of
328 ways. The following provides a basic overview of the capabilities:
334 The ACL plugin only operates on the Catalyst "private namespace". You
335 are using the private namespace when you use C<Local> actions. C<Path>,
336 C<Regex>, and C<Global> allow you to specify actions where the path and
337 the namespace differ -- the ACL plugin will not work in these cases.
341 Each rule is expressed in a separate
342 C<__PACKAGE__-E<gt>deny_access_unless()> or
343 C<__PACKAGE__-E<gt>allow_access_if()> line (there are several other
344 methods that can be used for more complex policies, see the C<METHODS>
346 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
347 documentation for more details).
351 Each rule can contain multiple roles but only a single path.
355 The rules are tried in order (with the "most specific" rules tested
356 first), and processing stops at the first "match" where an allow or deny
357 is specified. Rules "fall through" if there is not a "match" (where a
358 "match" means the user has the specified role). If a "match" is found,
359 then processing stops there and the appropriate allow/deny action is
364 If none of the rules match, then access is allowed.
368 The rules currently need to be specified in the application class
369 C<lib\MyApp.pm> B<after> the C<__PACKAGE__-E<gt>setup;> line.
374 =head2 Add a Method to Handle Access Violations
377 L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL>
378 throws an exception when authorization fails. This will take the user
379 to the Catalyst debug screen, or a "Please come back later" message if
380 you are not using the C<-Debug> flag. This step uses the
381 C<access_denied> method in order to provide more appropriate feedback to
384 Open C<lib/MyApp/Controller/Books.pm> in your editor and add the
389 Handle Catalyst::Plugin::Authorization::ACL access denied exceptions
393 sub access_denied : Private {
396 # Set the error message
397 $c->stash->{error_msg} = 'Unauthorized!';
403 Then run the Catalyst development server script:
405 $ script/myapp_server.pl
407 Log in as C<test02>. Once at the book list, click the "Create" link
408 to try the C<form_create> action. You should receive a red
409 "Unauthorized!" error message at the top of the list. (Note that in
410 the example code the "Create" link code in C<root/src/books/list.tt2>
411 is inside an C<IF> statement that only displays the list to
412 admin-level users.) If you log in as C<test01> you should be able to
413 view the C<form_create> form and add a new book.
415 When you are done, use one of the 'Logout' links (or go to the
416 L<http://localhost:3000/logout> URL directly) when you are done.
421 Kennedy Clark, C<hkclark@gmail.com>
423 Please report any errors, issues or suggestions to the author. The
424 most recent version of the Catalyst Tutorial can be found at
425 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.70/trunk/lib/Catalyst/Manual/Tutorial/>.
427 Copyright 2006-2008, Kennedy Clark, under Creative Commons License
428 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).