3 Catalyst::Manual::Tutorial::05_Authentication - Catalyst Tutorial - Chapter 5: Authentication
8 This is B<Chapter 5 of 10> for the Catalyst tutorial.
10 L<Tutorial Overview|Catalyst::Manual::Tutorial>
16 L<Introduction|Catalyst::Manual::Tutorial::01_Intro>
20 L<Catalyst Basics|Catalyst::Manual::Tutorial::02_CatalystBasics>
24 L<More Catalyst Basics|Catalyst::Manual::Tutorial::03_MoreCatalystBasics>
28 L<Basic CRUD|Catalyst::Manual::Tutorial::04_BasicCRUD>
36 L<Authorization|Catalyst::Manual::Tutorial::06_Authorization>
40 L<Debugging|Catalyst::Manual::Tutorial::07_Debugging>
44 L<Testing|Catalyst::Manual::Tutorial::08_Testing>
48 L<Advanced CRUD|Catalyst::Manual::Tutorial::09_AdvancedCRUD>
52 L<Appendices|Catalyst::Manual::Tutorial::10_Appendices>
59 Now that we finally have a simple yet functional application, we can
60 focus on providing authentication (with authorization coming next in
61 L<Chapter 6|Catalyst::Manual::Tutorial::06_Authorization>).
63 This chapter of the tutorial is divided into two main sections: 1)
64 basic, cleartext authentication and 2) hash-based authentication.
66 You can checkout the source code for this example from the catalyst
67 subversion repository as per the instructions in
68 L<Catalyst::Manual::Tutorial::01_Intro>.
71 =head1 BASIC AUTHENTICATION
73 This section explores how to add authentication logic to a Catalyst
77 =head2 Add Users and Roles to the Database
79 First, we add both user and role information to the database (we will
80 add the role information here although it will not be used until the
81 authorization section, Chapter 6). Create a new SQL script file by
82 opening C<myapp02.sql> in your editor and insert:
85 -- Add users and role tables, along with a many-to-many join table
87 PRAGMA foreign_keys = ON;
89 id INTEGER PRIMARY KEY,
98 id INTEGER PRIMARY KEY,
101 CREATE TABLE user_role (
102 user_id INTEGER REFERENCES users(id) ON DELETE CASCADE ON UPDATE CASCADE,
103 role_id INTEGER REFERENCES role(id) ON DELETE CASCADE ON UPDATE CASCADE,
104 PRIMARY KEY (user_id, role_id)
107 -- Load up some initial test data
109 INSERT INTO users VALUES (1, 'test01', 'mypass', 't01@na.com', 'Joe', 'Blow', 1);
110 INSERT INTO users VALUES (2, 'test02', 'mypass', 't02@na.com', 'Jane', 'Doe', 1);
111 INSERT INTO users VALUES (3, 'test03', 'mypass', 't03@na.com', 'No', 'Go', 0);
112 INSERT INTO role VALUES (1, 'user');
113 INSERT INTO role VALUES (2, 'admin');
114 INSERT INTO user_role VALUES (1, 1);
115 INSERT INTO user_role VALUES (1, 2);
116 INSERT INTO user_role VALUES (2, 1);
117 INSERT INTO user_role VALUES (3, 1);
119 Then load this into the C<myapp.db> database with the following command:
121 $ sqlite3 myapp.db < myapp02.sql
124 =head2 Add User and Role Information to DBIC Schema
126 Although we could manually edit the DBIC schema information to include
127 the new tables added in the previous step, let's use the
128 C<create=static> option on the DBIC model helper to do most of the work
131 $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
132 create=static components=TimeStamp dbi:SQLite:myapp.db \
133 on_connect_do="PRAGMA foreign_keys = ON"
134 exists "/root/dev/MyApp/script/../lib/MyApp/Model"
135 exists "/root/dev/MyApp/script/../t"
136 Dumping manual schema for MyApp::Schema to directory /root/dev/MyApp/script/../lib ...
137 Schema dump completed.
138 exists "/root/dev/MyApp/script/../lib/MyApp/Model/DB.pm"
140 $ ls lib/MyApp/Schema/Result
141 Author.pm BookAuthor.pm Book.pm Role.pm User.pm UserRole.pm
143 Notice how the helper has added three new table-specific Result Source
144 files to the C<lib/MyApp/Schema/Result> directory. And, more
145 importantly, even if there were changes to the existing result source
146 files, those changes would have only been written above the
147 C<# DO NOT MODIFY THIS OR ANYTHING ABOVE!> comment and your hand-edited
148 enhancements would have been preserved.
150 Speaking of "hand-edited enhancements," we should now add the
151 C<many_to_many> relationship information to the User Result Source file.
152 As with the Book, BookAuthor, and Author files in
153 L<Chapter 3|Catalyst::Manual::Tutorial::03_MoreCatalystBasics>,
154 L<DBIx::Class::Schema::Loader> has automatically created the C<has_many>
155 and C<belongs_to> relationships for the new User, UserRole, and Role
156 tables. However, as a convenience for mapping Users to their assigned
157 roles (see L<Chapter 6|Catalyst::Manual::Tutorial::06_Authorization>),
158 we will also manually add a C<many_to_many> relationship. Edit
159 C<lib/MyApp/Schema/Result/User.pm> add the following information between
160 the C<# DO NOT MODIFY THIS OR ANYTHING ABOVE!> comment and the closing
165 # 1) Name of relationship, DBIC will create accessor with this name
166 # 2) Name of has_many() relationship this many_to_many() is shortcut for
167 # 3) Name of belongs_to() relationship in model class of has_many() above
168 # You must already have the has_many() defined to use a many_to_many().
169 __PACKAGE__->many_to_many(roles => 'user_roles', 'role_id');
171 The code for this update is obviously very similar to the edits we made
172 to the C<Book> and C<Author> classes created in
173 L<Chapter 3|Catalyst::Manual::Tutorial::03_MoreCatalystBasics> with one
174 exception: we only defined the C<many_to_many> relationship in one
175 direction. Whereas we felt that we would want to map Authors to Books
176 B<AND> Books to Authors, here we are only adding the convenience
177 C<many_to_many> in the Users to Roles direction.
179 Note that we do not need to make any change to the
180 C<lib/MyApp/Schema.pm> schema file. It simply tells DBIC to load all of
181 the Result Class and ResultSet Class files it finds below the
182 C<lib/MyApp/Schema> directory, so it will automatically pick up our new
186 =head2 Sanity-Check of the Development Server Reload
188 We aren't ready to try out the authentication just yet; we only want to
189 do a quick check to be sure our model loads correctly. Assuming that you
190 are following along and using the "-r" option on C<myapp_server.pl>,
191 then the development server should automatically reload (if not, press
192 C<Ctrl-C> to break out of the server if it's running and then enter
193 C<script/myapp_server.pl> to start it). Look for the three new model
194 objects in the startup debug output:
197 .-------------------------------------------------------------------+----------.
199 +-------------------------------------------------------------------+----------+
200 | MyApp::Controller::Books | instance |
201 | MyApp::Controller::Root | instance |
202 | MyApp::Model::DB | instance |
203 | MyApp::Model::DB::Author | class |
204 | MyApp::Model::DB::Book | class |
205 | MyApp::Model::DB::BookAuthor | class |
206 | MyApp::Model::DB::Role | class |
207 | MyApp::Model::DB::User | class |
208 | MyApp::Model::DB::UserRole | class |
209 | MyApp::View::HTML | instance |
210 '-------------------------------------------------------------------+----------'
213 Again, notice that your "Result Class" classes have been "re-loaded" by
214 Catalyst under C<MyApp::Model>.
217 =head2 Include Authentication and Session Plugins
219 Edit C<lib/MyApp.pm> and update it as follows (everything below
220 C<StackTrace> is new):
234 Session::State::Cookie
237 B<Note:> As discussed in
238 L<Chapter 3|Catalyst::Manual::Tutorial::03_MoreCatalystBasics>,
239 different versions of C<Catalyst::Devel> have used a variety of methods
240 to load the plugins, but we are going to use the current Catalyst 5.9
241 practice of putting them on the C<use Catalyst> line.
243 The C<Authentication> plugin supports Authentication while the
244 C<Session> plugins are required to maintain state across multiple HTTP
247 Note that the only required Authentication class is the main one. This
248 is a change that occurred in version 0.09999_01 of the
249 L<Authentication|Catalyst::Plugin::Authentication> plugin. You
250 B<do not need> to specify a particular
251 L<Authentication::Store|Catalyst::Authentication::Store> or
252 C<Authentication::Credential> you want to use. Instead, indicate the
253 Store and Credential you want to use in your application configuration
256 Make sure you include the additional plugins as new dependencies in the
257 Makefile.PL file something like this:
259 requires 'Catalyst::Plugin::Authentication';
260 requires 'Catalyst::Plugin::Session';
261 requires 'Catalyst::Plugin::Session::Store::File';
262 requires 'Catalyst::Plugin::Session::State::Cookie';
264 Note that there are several options for
265 L<Session::Store|Catalyst::Plugin::Session::Store>.
266 L<Session::Store::Memcached|Catalyst::Plugin::Session::Store::Memcached>
267 is generally a good choice if you are on Unix. If you are running on
268 Windows L<Session::Store::File|Catalyst::Plugin::Session::Store::File>
269 is fine. Consult L<Session::Store|Catalyst::Plugin::Session::Store> and
270 its subclasses for additional information and options (for example to
271 use a database-backed session store).
274 =head2 Configure Authentication
276 There are a variety of ways to provide configuration information to
277 L<Catalyst::Plugin::Authentication>. Here we will use
278 L<Catalyst::Authentication::Realm::SimpleDB> because it automatically
279 sets a reasonable set of defaults for us. (Note: the C<SimpleDB> here
280 has nothing to do with the SimpleDB offered in Amazon's web services
281 offerings -- here we are only talking about a "simple" way to use your
282 DB as an authentication backend.) Open C<lib/MyApp.pm> and place the
283 following text above the call to C<__PACKAGE__-E<gt>setup();>:
285 # Configure SimpleDB Authentication
287 'Plugin::Authentication' => {
290 user_model => 'DB::User',
291 password_type => 'clear',
296 We could have placed this configuration in C<myapp.conf>, but placing it
297 in C<lib/MyApp.pm> is probably a better place since it's not likely
298 something that users of your application will want to change during
299 deployment (or you could use a mixture: leave C<class> and C<user_model>
300 defined in C<lib/MyApp.pm> as we show above, but place C<password_type>
301 in C<myapp.conf> to allow the type of password to be easily modified
302 during deployment). We will stick with putting all of the
303 authentication-related configuration in C<lib/MyApp.pm> for the
304 tutorial, but if you wish to use C<myapp.conf>, just convert to the
307 <Plugin::Authentication>
313 </Plugin::Authentication>
315 B<TIP:> Here is a short script that will dump the contents of
316 C<MyApp->config> to L<Config::General> format in C<myapp.conf>:
318 $ CATALYST_DEBUG=0 perl -Ilib -e 'use MyApp; use Config::General;
319 Config::General->new->save_file("myapp.conf", MyApp->config);'
321 B<HOWEVER>, if you try out the command above, be sure to delete the
322 "myapp.conf" command. Otherwise, you will wind up with duplicate
325 B<NOTE:> Because we are using
326 L<SimpleDB|L<Catalyst::Authentication::Realm::SimpleDB> along with a
327 database layout that complies with its default assumptions: we don't
328 need to specify the names of the columns where our username and password
329 information is stored (hence, the "Simple" part of "SimpleDB"). That
330 being said, SimpleDB lets you specify that type of information if you
331 need to. Take a look at C<Catalyst::Authentication::Realm::SimpleDB>
335 =head2 Add Login and Logout Controllers
337 Use the Catalyst create script to create two stub controller files:
339 $ script/myapp_create.pl controller Login
340 $ script/myapp_create.pl controller Logout
342 You could easily use a single controller here. For example, you could
343 have a C<User> controller with both C<login> and C<logout> actions.
344 Remember, Catalyst is designed to be very flexible, and leaves such
345 matters up to you, the designer and programmer.
347 Then open C<lib/MyApp/Controller/Login.pm>, and update the definition of
348 C<sub index> to match:
356 sub index :Path :Args(0) {
359 # Get the username and password from form
360 my $username = $c->request->params->{username};
361 my $password = $c->request->params->{password};
363 # If the username and password values were found in form
364 if ($username && $password) {
365 # Attempt to log the user in
366 if ($c->authenticate({ username => $username,
367 password => $password } )) {
368 # If successful, then let them use the application
369 $c->response->redirect($c->uri_for(
370 $c->controller('Books')->action_for('list')));
373 # Set an error message
374 $c->stash(error_msg => "Bad username or password.");
377 # Set an error message
378 $c->stash(error_msg => "Empty username or password.")
379 unless ($c->user_exists);
382 # If either of above don't work out, send to the login page
383 $c->stash(template => 'login.tt2');
386 This controller fetches the C<username> and C<password> values from the
387 login form and attempts to authenticate the user. If successful, it
388 redirects the user to the book list page. If the login fails, the user
389 will stay at the login page and receive an error message. If the
390 C<username> and C<password> values are not present in the form, the user
391 will be taken to the empty login form.
393 Note that we could have used something like "C<sub default :Path>",
394 however, it is generally recommended (partly for historical reasons, and
395 partly for code clarity) only to use C<default> in
396 C<MyApp::Controller::Root>, and then mainly to generate the 404 not
397 found page for the application.
399 Instead, we are using "C<sub somename :Path :Args(0) {...}>" here to
400 specifically match the URL C</login>. C<Path> actions (aka, "literal
401 actions") create URI matches relative to the namespace of the controller
402 where they are defined. Although C<Path> supports arguments that allow
403 relative and absolute paths to be defined, here we use an empty C<Path>
404 definition to match on just the name of the controller itself. The
405 method name, C<index>, is arbitrary. We make the match even more
406 specific with the C<:Args(0)> action modifier -- this forces the match
407 on I<only> C</login>, not C</login/somethingelse>.
409 Next, update the corresponding method in
410 C<lib/MyApp/Controller/Logout.pm> to match:
418 sub index :Path :Args(0) {
421 # Clear the user's state
424 # Send the user to the starting point
425 $c->response->redirect($c->uri_for('/'));
429 =head2 Add a Login Form TT Template Page
431 Create a login form by opening C<root/src/login.tt2> and inserting:
433 [% META title = 'Login' %]
436 <form method="post" action="[% c.uri_for('/login') %]">
440 <td><input type="text" name="username" size="40" /></td>
444 <td><input type="password" name="password" size="40" /></td>
447 <td colspan="2"><input type="submit" name="submit" value="Submit" /></td>
453 =head2 Add Valid User Check
455 We need something that provides enforcement for the authentication
456 mechanism -- a I<global> mechanism that prevents users who have not
457 passed authentication from reaching any pages except the login page.
458 This is generally done via an C<auto> action/method in
459 C<lib/MyApp/Controller/Root.pm>.
461 Edit the existing C<lib/MyApp/Controller/Root.pm> class file and insert
462 the following method:
466 Check if there is a user and, if not, forward to login page
470 # Note that 'auto' runs after 'begin' but before your actions and that
471 # 'auto's "chain" (all from application path to most specific class are run)
472 # See the 'Actions' section of 'Catalyst::Manual::Intro' for more info.
476 # Allow unauthenticated users to reach the login page. This
477 # allows unauthenticated users to reach any action in the Login
478 # controller. To lock it down to a single action, we could use:
479 # if ($c->action eq $c->controller('Login')->action_for('index'))
480 # to only allow unauthenticated access to the 'index' action we
482 if ($c->controller eq $c->controller('Login')) {
486 # If a user doesn't exist, force login
487 if (!$c->user_exists) {
488 # Dump a log message to the development server debug output
489 $c->log->debug('***Root::auto User not found, forwarding to /login');
490 # Redirect the user to the login page
491 $c->response->redirect($c->uri_for('/login'));
492 # Return 0 to cancel 'post-auto' processing and prevent use of application
496 # User found, so return 1 to continue with processing after this 'auto'
501 L<Catalyst::Manual::Tutorial::03_MoreCatalystBasics/CREATE A CATALYST CONTROLLER>,
502 every C<auto> method from the application/root controller down to the
503 most specific controller will be called. By placing the authentication
504 enforcement code inside the C<auto> method of
505 C<lib/MyApp/Controller/Root.pm> (or C<lib/MyApp.pm>), it will be called
506 for I<every> request that is received by the entire application.
509 =head2 Displaying Content Only to Authenticated Users
511 Let's say you want to provide some information on the login page that
512 changes depending on whether the user has authenticated yet. To do
513 this, open C<root/src/login.tt2> in your editor and add the following
514 lines to the bottom of the file:
519 # This code illustrates how certain parts of the TT
520 # template will only be shown to users who have logged in
522 [% IF c.user_exists %]
523 Please Note: You are already logged in as '[% c.user.username %]'.
524 You can <a href="[% c.uri_for('/logout') %]">logout</a> here.
526 You need to log in to use this application.
529 Note that this whole block is a comment because the "#" appears
530 immediate after the "[%" (with no spaces in between). Although it
531 can be a handy way to temporarily "comment out" a whole block of
532 TT code, it's probably a little too subtle for use in "normal"
537 Although most of the code is comments, the middle few lines provide a
538 "you are already logged in" reminder if the user returns to the login
539 page after they have already authenticated. For users who have not yet
540 authenticated, a "You need to log in..." message is displayed (note the
541 use of an IF-THEN-ELSE construct in TT).
544 =head2 Try Out Authentication
546 The development server should have reloaded each time we edited one of
547 the Controllers in the previous section. Now try going to
548 L<http://localhost:3000/books/list> and you should be redirected to the
549 login page, hitting Shift+Reload or Ctrl+Reload if necessary (the "You
550 are already logged in" message should I<not> appear -- if it does, click
551 the C<logout> button and try again). Note the C<***Root::auto User not
552 found...> debug message in the development server output. Enter username
553 C<test01> and password C<mypass>, and you should be taken to the Book
556 B<IMPORTANT NOTE:> If you are having issues with authentication on
557 Internet Explorer (or potentially other browsers), be sure to check the
558 system clocks on both your server and client machines. Internet
559 Explorer is very picky about timestamps for cookies. You can use the
560 C<ntpq -p> command on the Tutorial Virtual Machine to check time sync
561 and/or use the following command to force a sync:
565 Or, depending on your firewall configuration, try it with "-u":
567 sudo ntpdate-debian -u
569 Note: NTP can be a little more finicky about firewalls because it uses
570 UDP vs. the more common TCP that you see with most Internet protocols.
571 Worse case, you might have to manually set the time on your development
572 box instead of using NTP.
574 Open C<root/src/books/list.tt2> and add the following lines to the
575 bottom (below the closing </table> tag):
579 <a href="[% c.uri_for('/login') %]">Login</a>
580 <a href="[% c.uri_for(c.controller.action_for('form_create')) %]">Create</a>
583 Reload your browser and you should now see a "Login" and "Create" links
584 at the bottom of the page (as mentioned earlier, you can update template
585 files without a development server reload). Click the first link to
586 return to the login page. This time you I<should> see the "You are
587 already logged in" message.
589 Finally, click the C<You can logout here> link on the C</login> page.
590 You should stay at the login page, but the message should change to "You
591 need to log in to use this application."
594 =head1 USING PASSWORD HASHES
596 In this section we increase the security of our system by converting
597 from cleartext passwords to SHA-1 password hashes that include a random
598 "salt" value to make them extremely difficult to crack, even with
599 dictionary and "rainbow table" attacks.
601 B<Note:> This section is optional. You can skip it and the rest of the
602 tutorial will function normally.
604 Be aware that even with the techniques shown in this section, the
605 browser still transmits the passwords in cleartext to your application.
606 We are just avoiding the I<storage> of cleartext passwords in the
607 database by using a salted SHA-1 hash. If you are concerned about
608 cleartext passwords between the browser and your application, consider
609 using SSL/TLS, made easy with modules such as
610 L<Catalyst::Plugin:RequireSSL> and L<Catalyst::ActionRole::RequireSSL>.
613 =head2 Re-Run the DBIC::Schema Model Helper to Include DBIx::Class::PassphraseColumn
615 Let's re-run the model helper to have it include
616 L<DBIx::Class::PassphraseColumn> in all of the Result Classes it
617 generates for us. Simply use the same command we saw in Chapters 3 and
618 4, but add C<,PassphraseColumn> to the C<components> argument:
620 $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
621 create=static components=TimeStamp,PassphraseColumn dbi:SQLite:myapp.db \
622 on_connect_do="PRAGMA foreign_keys = ON"
624 If you then open one of the Result Classes, you will see that it
625 includes PassphraseColumn in the C<load_components> line. Take a look
626 at C<lib/MyApp/Schema/Result/User.pm> since that's the main class where
627 we want to use hashed and salted passwords:
629 __PACKAGE__->load_components("InflateColumn::DateTime", "TimeStamp", "PassphraseColumn");
632 =head2 Modify the "password" Column to Use PassphraseColumn
634 Open the file C<lib/MyApp/Schema/Result/User.pm> and enter the following
635 text below the "# DO NOT MODIFY THIS OR ANYTHING ABOVE!" line but above
638 # Have the 'password' column use a SHA-1 hash and 20-byte salt
639 # with RFC 2307 encoding; Generate the 'check_password" method
640 __PACKAGE__->add_columns(
642 passphrase => 'rfc2307',
643 passphrase_class => 'SaltedDigest',
645 algorithm => 'SHA-1',
648 passphrase_check_method => 'check_password',
652 This redefines the automatically generated definition for the password
653 fields at the top of the Result Class file to now use PassphraseColumn
654 logic, storing passwords in RFC 2307 format (C<passphrase> is set to
655 C<rfc2307>). C<passphrase_class> can be set to the name of any
656 C<Authen::Passphrase::*> class, such as C<SaltedDigest> to use
657 L<Authen::Passphrase::SaltedDigest>, or C<BlowfishCrypt> to use
658 L<Authen::Passphrase::BlowfishCrypt>. C<passphrase_args> is then used
659 to customize the passphrase class you selected. Here we specified the
660 digest algorithm to use as C<SHA-1> and the size of the salt to use, but
661 we could have also specified any other option the selected passphrase
665 =head2 Load Hashed Passwords in the Database
667 Next, let's create a quick script to load some hashed and salted
668 passwords into the C<password> column of our C<users> table. Open the
669 file C<set_hashed_passwords.pl> in your editor and enter the following
679 my $schema = MyApp::Schema->connect('dbi:SQLite:myapp.db');
681 my @users = $schema->resultset('User')->all;
683 foreach my $user (@users) {
684 $user->password('mypass');
688 PassphraseColumn lets us simply call C<$user->check_password($password)>
689 to see if the user has supplied the correct password, or, as we show
690 above, call C<$user->update($new_password)> to update the hashed
691 password stored for this user.
693 Then run the following command:
695 $ DBIC_TRACE=1 perl -Ilib set_hashed_passwords.pl
697 We had to use the C<-Ilib> argument to tell perl to look under the
698 C<lib> directory for our C<MyApp::Schema> model.
700 The DBIC_TRACE output should show that the update worked:
702 $ DBIC_TRACE=1 perl -Ilib set_hashed_passwords.pl
703 SELECT me.id, me.username, me.password, me.email_address,
704 me.first_name, me.last_name, me.active FROM users me:
705 UPDATE users SET password = ? WHERE ( id = ? ):
706 '{SSHA}esgz64CpHMo8pMfgIIszP13ft23z/zio04aCwNdm0wc6MDeloMUH4g==', '1'
707 UPDATE users SET password = ? WHERE ( id = ? ):
708 '{SSHA}FpGhpCJus+Ea9ne4ww8404HH+hJKW/fW+bAv1v6FuRUy2G7I2aoTRQ==', '2'
709 UPDATE users SET password = ? WHERE ( id = ? ):
710 '{SSHA}ZyGlpiHls8qFBSbHr3r5t/iqcZE602XLMbkSVRRNl6rF8imv1abQVg==', '3'
712 But we can further confirm our actions by dumping the users table:
714 $ sqlite3 myapp.db "select * from users"
715 1|test01|{SSHA}esgz64CpHMo8pMfgIIszP13ft23z/zio04aCwNdm0wc6MDeloMUH4g==|t01@na.com|Joe|Blow|1
716 2|test02|{SSHA}FpGhpCJus+Ea9ne4ww8404HH+hJKW/fW+bAv1v6FuRUy2G7I2aoTRQ==|t02@na.com|Jane|Doe|1
717 3|test03|{SSHA}ZyGlpiHls8qFBSbHr3r5t/iqcZE602XLMbkSVRRNl6rF8imv1abQVg==|t03@na.com|No|Go|0
719 As you can see, the passwords are much harder to steal from the database
720 (not only are the hashes stored, but every hash is different even though
721 the passwords are the same because of the added "salt" value). Also
722 note that this demonstrates how to use a DBIx::Class model outside of
723 your web application -- a very useful feature in many situations.
726 =head2 Enable Hashed and Salted Passwords
728 Edit C<lib/MyApp.pm> and update the config() section for
729 C<Plugin::Authentication> it to match the following text (the only
730 change is to the C<password_type> field):
732 # Configure SimpleDB Authentication
734 'Plugin::Authentication' => {
737 user_model => 'DB::User',
738 password_type => 'self_check',
743 The use of C<self_check> will cause
744 Catalyst::Plugin::Authentication::Store::DBIC to call the
745 C<check_password> method we enabled on our C<password> columns.
748 =head2 Try Out the Hashed Passwords
750 The development server should restart as soon as your save the
751 C<lib/MyApp.pm> file in the previous section. You should now be able to
752 go to L<http://localhost:3000/books/list> and login as before. When
753 done, click the "logout" link on the login page (or point your browser
754 at L<http://localhost:3000/logout>).
757 =head1 USING THE SESSION FOR FLASH
759 As discussed in the previous chapter of the tutorial, C<flash> allows
760 you to set variables in a way that is very similar to C<stash>, but it
761 will remain set across multiple requests. Once the value is read, it is
762 cleared (unless reset). Although C<flash> has nothing to do with
763 authentication, it does leverage the same session plugins. Now that
764 those plugins are enabled, let's go back and update the "delete and
765 redirect with query parameters" code seen at the end of the
766 L<Basic CRUD|Catalyst::Manual::Tutorial::04_BasicCRUD> chapter of the
767 tutorial to take advantage of C<flash>.
769 First, open C<lib/MyApp/Controller/Books.pm> and modify C<sub delete> to
770 match the following (everything after the model search line of code has
779 sub delete :Chained('object') :PathPart('delete') :Args(0) {
782 # Use the book object saved by 'object' and delete it along
783 # with related 'book_authors' entries
784 $c->stash->{object}->delete;
786 # Use 'flash' to save information across requests until it's read
787 $c->flash->{status_msg} = "Book deleted";
789 # Redirect the user back to the list page
790 $c->response->redirect($c->uri_for($self->action_for('list')));
793 Next, open C<root/src/wrapper.tt2> and update the TT code to pull from
794 flash vs. the C<status_msg> query parameter:
798 [%# Status and error messages %]
799 <span class="message">[% status_msg || c.flash.status_msg %]</span>
800 <span class="error">[% error_msg %]</span>
801 [%# This is where TT will stick all of your template's contents. -%]
803 </div><!-- end content -->
806 Although the sample above only shows the C<content> div, leave the rest
807 of the file intact -- the only change we made to replace "||
808 c.request.params.status_msg" with "c.flash.status_msg" in the
809 C<E<lt>span class="message"E<gt>> line.
814 Authenticate using the login screen and then point your browser to
815 L<http://localhost:3000/books/url_create/Test/1/4> to create an extra
816 several books. Click the "Return to list" link and delete one of the
817 "Test" books you just added. The C<flash> mechanism should retain our
818 "Book deleted" status message across the redirect.
820 B<NOTE:> While C<flash> will save information across multiple requests,
821 I<it does get cleared the first time it is read>. In general, this is
822 exactly what you want -- the C<flash> message will get displayed on the
823 next screen where it's appropriate, but it won't "keep showing up" after
824 that first time (unless you reset it). Please refer to
825 L<Catalyst::Plugin::Session> for additional information.
827 B<Note:> There is also a C<flash-to-stash> feature that will
828 automatically load the contents the contents of flash into stash,
829 allowing us to use the more typical C<c.flash.status_msg> in our TT
830 template in lieu of the more verbose C<status_msg || c.flash.status_msg>
831 we used above. Consult L<Catalyst::Plugin::Session> for additional
835 =head2 Switch To Catalyst::Plugin::StatusMessages
837 Although the query parameter technique we used in
838 L<Chapter 4|Catalyst::Manual::Tutorial::04_BasicCRUD> and the C<flash>
839 approach we used above will work in most cases, they both have their
840 drawbacks. The query parameters can leave the status message on the
841 screen longer than it should (for example, if the user hits refresh).
842 And C<flash> can display the wrong message on the wrong screen (flash
843 just shows the message on the next page for that user... if the user
844 has multiple windows or tabs open, then the wrong one can get the
847 L<Catalyst::Plugin::StatusMessage> is designed to address these
848 shortcomings. It stores the messages in the user's session (so they are
849 available across multiple requests), but ties each status message to a
850 random token. By passing this token across the redirect, we are no
851 longer relying on a potentially ambiguous "next request" like we do with
852 flash. And, because the message is deleted the first time it's
853 displayed, the user can hit refresh and still only see the message a
854 single time (even though the URL may continue to reference the token,
855 it's only displayed the first time). The use of C<StatusMessage>
856 or a similar mechanism is recommended for all Catalyst applications.
858 To enable C<StatusMessage>, first edit C<lib/MyApp.pm> and add
859 C<StatusMessage> to the list of plugins:
870 Session::State::Cookie
875 Then edit C<lib/MyApp/Controller/Books.pm> and modify the C<delete>
876 action to match the following:
878 sub delete :Chained('object') :PathPart('delete') :Args(0) {
881 # Saved the PK id for status_msg below
882 my $id = $c->stash->{object}->id;
884 # Use the book object saved by 'object' and delete it along
885 # with related 'book_authors' entries
886 $c->stash->{object}->delete;
888 # Redirect the user back to the list page
889 $c->response->redirect($c->uri_for($self->action_for('list'),
890 {mid => $c->set_status_msg("Deleted book $id")}));
893 This uses the C<set_status_msg> that the plugin added to C<$c> to save
894 the message under a random token. (If we wanted to save an error
895 message, we could have used C<set_error_msg>.) Because
896 C<set_status_msg> and C<set_error_msg> both return the random token, we
897 can assign that value to the "C<mid>" query parameter via C<uri_for> as
900 Next, we need to make sure that the list page will load display the
901 message. The easiest way to do this is to take advantage of the chained
902 dispatch we implemented in
903 L<Chapter 4|Catalyst::Manual::Tutorial::04_BasicCRUD>. Edit
904 C<lib/MyApp/Controller/Books.pm> again and update the C<base> action to
907 sub base :Chained('/') :PathPart('books') :CaptureArgs(0) {
910 # Store the ResultSet in stash so it's available for other methods
911 $c->stash(resultset => $c->model('DB::Book'));
913 # Print a message to the debug log
914 $c->log->debug('*** INSIDE BASE METHOD ***');
916 # Load status messages
917 $c->load_status_msgs;
920 That way, anything that chains off C<base> will automatically get any
921 status or error messages loaded into the stash. Let's convert the
922 C<list> action to take advantage of this. Modify the method signature
929 sub list :Chained('base') :PathParth('list') :Args(0) {
931 Finally, let's clean up the status/error message code in our wrapper
932 template. Edit C<root/src/wrapper.tt2> and change the "content" div
933 to match the following:
936 [%# Status and error messages %]
937 <span class="message">[% status_msg %]</span>
938 <span class="error">[% error_msg %]</span>
939 [%# This is where TT will stick all of your template's contents. -%]
941 </div><!-- end content -->
943 Now go to L<http://localhost:3000/books/list> in your browser. Delete
944 another of the "Test" books you added in the previous step. You should
945 get redirection from the C<delete> action back to the C<list> action,
946 but with a "mid=########" message ID query parameter. The screen should
947 say "Deleted book #" (where # is the PK id of the book you removed).
948 However, if you hit refresh in your browser, the status message is no
949 longer displayed (even though the URL does still contain the message ID
950 token, it is ignored -- thereby keeping the state of our status/error
951 messages in sync with the users actions).
956 Kennedy Clark, C<hkclark@gmail.com>
958 Feel free to contact the author for any errors or suggestions, but the
959 best way to report issues is via the CPAN RT Bug system at
960 <https://rt.cpan.org/Public/Dist/Display.html?Name=Catalyst-Manual>.
962 The most recent version of the Catalyst Tutorial can be found at
963 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
965 Copyright 2006-2010, Kennedy Clark, under the
966 Creative Commons Attribution Share-Alike License Version 3.0
967 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).