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1 | =head1 NAME |
2 | |
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3 | Catalyst::Manual::Tutorial::Authorization - Catalyst Tutorial - Part 5: Authorization |
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4 | |
5 | |
6 | =head1 OVERVIEW |
7 | |
8 | This is B<Part 5 of 9> for the Catalyst tutorial. |
9 | |
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10 | L<Tutorial Overview|Catalyst::Manual::Tutorial> |
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11 | |
12 | =over 4 |
13 | |
14 | =item 1 |
15 | |
16 | L<Introduction|Catalyst::Manual::Tutorial::Intro> |
17 | |
18 | =item 2 |
19 | |
20 | L<Catalyst Basics|Catalyst::Manual::Tutorial::CatalystBasics> |
21 | |
22 | =item 3 |
23 | |
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24 | L<Basic CRUD|Catalyst::Manual::Tutorial_BasicCRUD> |
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25 | |
26 | =item 4 |
27 | |
28 | L<Authentication|Catalyst::Manual::Tutorial::Authentication> |
29 | |
30 | =item 5 |
31 | |
32 | B<Authorization> |
33 | |
34 | =item 6 |
35 | |
36 | L<Debugging|Catalyst::Manual::Tutorial::Debugging> |
37 | |
38 | =item 7 |
39 | |
40 | L<Testing|Catalyst::Manual::Tutorial::Testing> |
41 | |
42 | =item 8 |
43 | |
44 | L<AdvancedCRUD|Catalyst::Manual::Tutorial::AdvancedCRUD> |
45 | |
46 | =item 9 |
47 | |
48 | L<Appendicies|Catalyst::Manual::Tutorial::Appendicies> |
49 | |
50 | =back |
51 | |
52 | |
53 | |
54 | =head1 DESCRIPTION |
55 | |
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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. |
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61 | |
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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 |
64 | following command: |
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65 | |
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. |
68 | |
69 | |
70 | |
71 | =head1 BASIC AUTHORIZATION |
72 | |
73 | In this section you learn how to manually configure authorization. |
74 | |
75 | |
76 | =head2 Update Plugins to Include Support Authorization |
77 | |
78 | Edit C<lib/MyApp.pm> and add C<Authorization::Roles> to the list: |
79 | |
80 | use Catalyst qw/ |
81 | -Debug |
82 | ConfigLoader |
83 | Static::Simple |
84 | |
85 | Dumper |
86 | StackTrace |
87 | DefaultEnd |
88 | |
89 | Authentication |
90 | Authentication::Store::DBIC |
91 | Authentication::Credential::Password |
92 | Authorization::Roles |
93 | |
94 | Session |
95 | Session::Store::FastMmap |
96 | Session::State::Cookie |
97 | /; |
98 | |
99 | |
100 | =head2 Add Config Information for Authorization |
101 | |
102 | Edit C<myapp.yml> and update it to match (everything from the "authorization:" line down is new): |
103 | |
104 | --- |
105 | name: MyApp |
106 | authentication: |
107 | dbic: |
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). |
111 | # |
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 |
118 | user_field: username |
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 |
126 | authorization: |
127 | dbic: |
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 |
134 | role_field: role |
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 |
140 | |
141 | |
142 | =head2 Add Role-Specific Logic to the "Book List" Template |
143 | |
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144 | Open C<root/src/books/list.tt2> in your editor and add the following |
145 | lines to the bottom of the file: |
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146 | |
147 | <p>Hello [% Catalyst.user.username %], you have the following roles:</p> |
148 | |
149 | <ul> |
150 | [% # Dump list of roles -%] |
151 | [% FOR role = Catalyst.user.roles %]<li>[% role %]</li>[% END %] |
152 | </ul> |
153 | |
154 | <p> |
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> |
160 | [% END %] |
161 | |
162 | [% # Can also use $c->user->check_roles() to check authz -%] |
163 | [% IF Catalyst.check_user_roles('admin') %] |
164 | [% # Give admin users a link for 'create' %] |
165 | <a href="[% Catalyst.uri_for('form_create') %]">Create</a> |
166 | [% END %] |
167 | </p> |
168 | |
169 | This code displays a different combination of links depending on the roles assigned to the user.. |
170 | |
171 | |
172 | =head2 Limit C<Books::add> to C<admin> Users |
173 | |
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174 | C<IF> statements in TT templates simply control the output that is sent |
175 | to the user's browser; it provides no real enforcement (if users know or |
176 | guess the appropriate URLs, they are still perfectly free to hit any |
177 | action within your application). We need to enhance the controller |
178 | logic to wrap restricted actions with role validation logic. |
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179 | |
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180 | For example, we might want to restrict the "formless create" action to |
181 | admin-level users by editing C<lib/MyApp/Controller/Books.pm> and |
182 | updating C<url_create> to match the following code: |
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183 | |
184 | =head2 url_create |
185 | |
186 | Create a book with the supplied title, and rating |
187 | with manual authorization |
188 | |
189 | =cut |
190 | |
191 | sub url_create : Local { |
192 | # In addition to self & context, get the title, rating & author_id args |
193 | # from the URL. Note that Catalyst automatically puts extra information |
194 | # after the "/<controller_name>/<action_name/" into @_ |
195 | my ($self, $c, $title, $rating, $author_id) = @_; |
196 | |
197 | # Check the user's roles |
198 | if ($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({ |
202 | title => $title, |
203 | rating => $rating |
204 | }); |
205 | |
206 | # Add a record to the join table for this book, mapping to |
207 | # appropriate author |
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}); |
211 | |
212 | # Assign the Book object to the stash for display in the view |
213 | $c->stash->{book} = $book; |
214 | |
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; |
222 | |
223 | # Set the TT template to use |
224 | $c->stash->{template} = 'books/create_done.tt2'; |
225 | } else { |
226 | # Provide very simple feedback to the user |
227 | $c->response->body('Unauthorized!'); |
228 | } |
229 | } |
230 | |
231 | |
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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 |
240 | Part 2). |
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241 | |
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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<}>. |
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246 | |
247 | |
248 | =head2 Try Out Authentication And Authorization |
249 | |
250 | Press C<Ctrl-C> to kill the previous server instance (if it's still running) and restart it: |
251 | |
252 | $ script/myapp_server.pl |
253 | |
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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 |
259 | book list page. |
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260 | |
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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 |
263 | C<test02>. Try: |
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264 | |
265 | http://localhost:3000/books/url_create/test/1/6 |
266 | |
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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 |
269 | done. |
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270 | |
271 | |
272 | |
273 | =head1 ENABLE ACL-BASED AUTHORIZATION |
274 | |
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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. |
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279 | |
280 | |
281 | =head2 Add the C<Catalyst::Plugin::Authorization::ACL> Plugin |
282 | |
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283 | Open C<lib/MyApp.pm> in your editor and add the following plugin to the |
284 | C<use Catalyst> statement: |
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285 | |
286 | Authorization::ACL |
287 | |
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288 | Note that the remaining C<use Catalyst> plugins from earlier sections |
289 | are not shown here, but they should still be included. |
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290 | |
291 | |
292 | =head2 Add ACL Rules to the Application Class |
293 | |
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294 | Open C<lib/MyApp.pm> in your editor and add the following B<BELOW> the |
295 | C<__PACKAGE__-E<gt>setup;> statement: |
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296 | |
297 | # Authorization::ACL Rules |
298 | __PACKAGE__->deny_access_unless( |
299 | "/books/form_create", |
300 | [qw/admin/], |
301 | ); |
302 | __PACKAGE__->deny_access_unless( |
303 | "/books/form_create_do", |
304 | [qw/admin/], |
305 | ); |
306 | __PACKAGE__->deny_access_unless( |
307 | "/books/delete", |
308 | [qw/user admin/], |
309 | ); |
310 | |
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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 |
317 | the tutorial. |
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318 | |
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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: |
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321 | |
322 | =over 4 |
323 | |
324 | =item * |
325 | |
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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. |
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330 | |
331 | =item * |
332 | |
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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> |
337 | portion of the |
338 | L<Catalyst::Plugin::Authorization::ACL|Catalyst::Plugin::Authorization::ACL> |
339 | documentation for more details). |
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340 | |
341 | =item * |
342 | |
343 | Each rule can contain multiple roles but only a single path. |
344 | |
345 | =item * |
346 | |
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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 |
352 | taken. |
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353 | |
354 | =item * |
355 | |
356 | If none of the rules match, then access is allowed. |
357 | |
358 | =item * |
359 | |
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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. |
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362 | |
363 | =back |
364 | |
365 | |
366 | =head2 Add a Method to Handle Access Violations |
367 | |
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368 | By default, |
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 |
374 | the user. |
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375 | |
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376 | Open C<lib/MyApp/Controller/Books.pm> in your editor and add the |
377 | following method: |
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378 | |
379 | =head2 access_denied |
380 | |
381 | Handle Catalyst::Plugin::Authorization::ACL access denied exceptions |
382 | |
383 | =cut |
384 | |
385 | sub access_denied : Private { |
386 | my ($self, $c) = @_; |
387 | |
388 | # Set the error message |
389 | $c->stash->{error_msg} = 'Unauthorized!'; |
390 | |
391 | # Display the list |
392 | $c->forward('list'); |
393 | } |
394 | |
395 | |
396 | Then run the Catalyst development server script: |
397 | |
398 | $ script/myapp_server.pl |
399 | |
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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. |
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407 | |
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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. |
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410 | |
411 | |
412 | |
413 | =head1 AUTHOR |
414 | |
415 | Kennedy Clark, C<hkclark@gmail.com> |
416 | |
417 | Please report any errors, issues or suggestions to the author. |
418 | |
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419 | Copyright 2006, Kennedy Clark, under Creative Commons License (L<http://creativecommons.org/licenses/by-nc-sa/2.5/>). |
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420 | |
421 | Version: .94 |
422 | |