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 C<# DO NOT
147 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 L<Chapter
153 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 Chapter 3 with one
173 exception: we only defined the C<many_to_many> relationship in one
174 direction. Whereas we felt that we would want to map Authors to Books
175 B<AND> Books to Authors, here we are only adding the convenience
176 C<many_to_many> in the Users to Roles direction.
178 Note that we do not need to make any change to the
179 C<lib/MyApp/Schema.pm> schema file. It simply tells DBIC to load all of
180 the Result Class and ResultSet Class files it finds in below the
181 C<lib/MyApp/Schema> directory, so it will automatically pick up our new
185 =head2 Sanity-Check of the Development Server Reload
187 We aren't ready to try out the authentication just yet; we only want to
188 do a quick check to be sure our model loads correctly. Assuming that you
189 are following along and using the "-r" option on C<myapp_server.pl>,
190 then the development server should automatically reload (if not, press
191 C<Ctrl-C> to break out of the server if it's running and then enter
192 C<script/myapp_server.pl> to start it). Look for the three new model
193 objects in the startup debug output:
196 .-------------------------------------------------------------------+----------.
198 +-------------------------------------------------------------------+----------+
199 | MyApp::Controller::Books | instance |
200 | MyApp::Controller::Root | instance |
201 | MyApp::Model::DB | instance |
202 | MyApp::Model::DB::Author | class |
203 | MyApp::Model::DB::Book | class |
204 | MyApp::Model::DB::BookAuthor | class |
205 | MyApp::Model::DB::Role | class |
206 | MyApp::Model::DB::User | class |
207 | MyApp::Model::DB::UserRole | class |
208 | MyApp::View::HTML | instance |
209 '-------------------------------------------------------------------+----------'
212 Again, notice that your "Result Class" classes have been "re-loaded" by
213 Catalyst under C<MyApp::Model>.
216 =head2 Include Authentication and Session Plugins
218 Edit C<lib/MyApp.pm> and update it as follows (everything below
219 C<StackTrace> is new):
233 Session::State::Cookie
236 B<Note:> As discussed in MoreCatalystBasics, different versions of
237 C<Catalyst::Devel> have used a variety of methods to load the plugins,
238 but we are going to use the current Catalyst 5.8X practice of putting
239 them on the C<use Catalyst> line.
241 The C<Authentication> plugin supports Authentication while the
242 C<Session> plugins are required to maintain state across multiple HTTP
245 Note that the only required Authentication class is the main one. This
246 is a change that occurred in version 0.09999_01 of the C<Authentication>
247 plugin. You B<do not need> to specify a particular Authentication::Store
248 or Authentication::Credential plugin. Instead, indicate the Store and
249 Credential you want to use in your application configuration (see
252 Make sure you include the additional plugins as new dependencies in the
253 Makefile.PL file something like this:
255 requires 'Catalyst::Plugin::Authentication';
256 requires 'Catalyst::Plugin::Session';
257 requires 'Catalyst::Plugin::Session::Store::File';
258 requires 'Catalyst::Plugin::Session::State::Cookie';
260 Note that there are several options for
261 L<Session::Store|Catalyst::Plugin::Session::Store>.
262 L<Session::Store::Memcached|Catalyst::Plugin::Session::Store::Memcached>
263 is generally a good choice if you are on Unix. If you are running on
264 Windows L<Session::Store::File|Catalyst::Plugin::Session::Store::File>
265 is fine. Consult L<Session::Store|Catalyst::Plugin::Session::Store> and
266 its subclasses for additional information and options (for example to
267 use a database- backed session store).
270 =head2 Configure Authentication
272 There are a variety of ways to provide configuration information to
273 L<Catalyst::Plugin::Authentication>. Here we will use
274 L<Catalyst::Authentication::Realm::SimpleDB> because it automatically
275 sets a reasonable set of defaults for us. Open C<lib/MyApp.pm> and place
276 the following text above the call to C<__PACKAGE__-E<gt>setup();>:
278 # Configure SimpleDB Authentication
280 'Plugin::Authentication' => {
283 user_model => 'DB::User',
284 password_type => 'clear',
289 We could have placed this configuration in C<myapp.conf>, but placing it
290 in C<lib/MyApp.pm> is probably a better place since it's not likely
291 something that users of your application will want to change during
292 deployment (or you could use a mixture: leave C<class> and C<user_model>
293 defined in C<lib/MyApp.pm> as we show above, but place C<password_type>
294 in C<myapp.conf> to allow the type of password to be easily modified
295 during deployment). We will stick with putting all of the
296 authentication-related configuration in C<lib/MyApp.pm> for the
297 tutorial, but if you wish to use C<myapp.conf>, just convert to the
300 <Plugin::Authentication>
306 </Plugin::Authentication>
308 B<TIP:> Here is a short script that will dump the contents of
309 C<MyApp->config> to L<Config::General> format in C<myapp.conf>:
311 $ CATALYST_DEBUG=0 perl -Ilib -e 'use MyApp; use Config::General;
312 Config::General->new->save_file("myapp.conf", MyApp->config);'
314 B<HOWEVER>, if you try out the command above, be sure to delete the
315 "myapp.conf" command. Otherwise, you will wind up with duplicate
318 B<NOTE:> Because we are using SimpleDB along with a database layout that
319 complies with its default assumptions: we don't need to specify the
320 names of the columns where our username and password information is
321 stored (hence, the "Simple" part of "SimpleDB"). That being said,
322 SimpleDB lets you specify that type of information if you need to. Take
324 C<Catalyst::Authentication::Realm::SimpleDB|Catalyst::Authentication::Realm::SimpleDB>
328 =head2 Add Login and Logout Controllers
330 Use the Catalyst create script to create two stub controller files:
332 $ script/myapp_create.pl controller Login
333 $ script/myapp_create.pl controller Logout
335 You could easily use a single controller here. For example, you could
336 have a C<User> controller with both C<login> and C<logout> actions.
337 Remember, Catalyst is designed to be very flexible, and leaves such
338 matters up to you, the designer and programmer.
340 Then open C<lib/MyApp/Controller/Login.pm>, locate the
341 C<sub index :Path :Args(0)> method (or C<sub index : Private> if you are
342 using an older version of Catalyst) that was automatically inserted by
343 the helpers when we created the Login controller above, and update the
344 definition of C<sub index> to match:
352 sub index :Path :Args(0) {
355 # Get the username and password from form
356 my $username = $c->request->params->{username};
357 my $password = $c->request->params->{password};
359 # If the username and password values were found in form
360 if ($username && $password) {
361 # Attempt to log the user in
362 if ($c->authenticate({ username => $username,
363 password => $password } )) {
364 # If successful, then let them use the application
365 $c->response->redirect($c->uri_for(
366 $c->controller('Books')->action_for('list')));
369 # Set an error message
370 $c->stash(error_msg => "Bad username or password.");
373 # Set an error message
374 $c->stash(error_msg => "Empty username or password.")
375 unless ($c->user_exists);
378 # If either of above don't work out, send to the login page
379 $c->stash(template => 'login.tt2');
382 Be sure to remove the
383 C<$c-E<gt>response-E<gt>body('Matched MyApp::Controller::Login in Login.');>
384 line of the C<sub index>.
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('/'));
428 As with the login controller, be sure to delete the
429 C<$c-E<gt>response-E<gt>body('Matched MyApp::Controller::Logout in Logout.');>
430 line of the C<sub index>.
433 =head2 Add a Login Form TT Template Page
435 Create a login form by opening C<root/src/login.tt2> and inserting:
437 [% META title = 'Login' %]
440 <form method="post" action="[% c.uri_for('/login') %]">
444 <td><input type="text" name="username" size="40" /></td>
448 <td><input type="password" name="password" size="40" /></td>
451 <td colspan="2"><input type="submit" name="submit" value="Submit" /></td>
457 =head2 Add Valid User Check
459 We need something that provides enforcement for the authentication
460 mechanism -- a I<global> mechanism that prevents users who have not
461 passed authentication from reaching any pages except the login page.
462 This is generally done via an C<auto> action/method in
463 C<lib/MyApp/Controller/Root.pm>.
465 Edit the existing C<lib/MyApp/Controller/Root.pm> class file and insert
466 the following method:
470 Check if there is a user and, if not, forward to login page
474 # Note that 'auto' runs after 'begin' but before your actions and that
475 # 'auto's "chain" (all from application path to most specific class are run)
476 # See the 'Actions' section of 'Catalyst::Manual::Intro' for more info.
480 # Allow unauthenticated users to reach the login page. This
481 # allows unauthenticated users to reach any action in the Login
482 # controller. To lock it down to a single action, we could use:
483 # if ($c->action eq $c->controller('Login')->action_for('index'))
484 # to only allow unauthenticated access to the 'index' action we
486 if ($c->controller eq $c->controller('Login')) {
490 # If a user doesn't exist, force login
491 if (!$c->user_exists) {
492 # Dump a log message to the development server debug output
493 $c->log->debug('***Root::auto User not found, forwarding to /login');
494 # Redirect the user to the login page
495 $c->response->redirect($c->uri_for('/login'));
496 # Return 0 to cancel 'post-auto' processing and prevent use of application
500 # User found, so return 1 to continue with processing after this 'auto'
505 L<Catalyst::Manual::Tutorial::03_MoreCatalystBasics/CREATE A CATALYST CONTROLLER>,
506 every C<auto> method from the application/root controller down to the
507 most specific controller will be called. By placing the authentication
508 enforcement code inside the C<auto> method of
509 C<lib/MyApp/Controller/Root.pm> (or C<lib/MyApp.pm>), it will be called
510 for I<every> request that is received by the entire application.
513 =head2 Displaying Content Only to Authenticated Users
515 Let's say you want to provide some information on the login page that
516 changes depending on whether the user has authenticated yet. To do
517 this, open C<root/src/login.tt2> in your editor and add the following
518 lines to the bottom of the file:
523 # This code illustrates how certain parts of the TT
524 # template will only be shown to users who have logged in
526 [% IF c.user_exists %]
527 Please Note: You are already logged in as '[% c.user.username %]'.
528 You can <a href="[% c.uri_for('/logout') %]">logout</a> here.
530 You need to log in to use this application.
533 Note that this whole block is a comment because the "#" appears
534 immediate after the "[%" (with no spaces in between). Although it
535 can be a handy way to temporarily "comment out" a whole block of
536 TT code, it's probably a little too subtle for use in "normal"
541 Although most of the code is comments, the middle few lines provide a
542 "you are already logged in" reminder if the user returns to the login
543 page after they have already authenticated. For users who have not yet
544 authenticated, a "You need to log in..." message is displayed (note the
545 use of an IF-THEN-ELSE construct in TT).
548 =head2 Try Out Authentication
550 The development server should have reloaded each time we edited one of
551 the Controllers in the previous section. Now try going to
552 L<http://localhost:3000/books/list> and you should be redirected to the
553 login page, hitting Shift+Reload or Ctrl+Reload if necessary (the "You
554 are already logged in" message should I<not> appear -- if it does, click
555 the C<logout> button and try again). Note the C<***Root::auto User not
556 found...> debug message in the development server output. Enter username
557 C<test01> and password C<mypass>, and you should be taken to the Book
560 B<IMPORTANT NOTE:> If you are having issues with authentication on
561 Internet Explorer, be sure to check the system clocks on both your
562 server and client machines. Internet Explorer is very picky about
563 timestamps for cookies. You can quickly sync a Debian system by
564 installing the "ntpdate" package:
566 sudo aptitude -y install ntpdate
568 And then run the following command:
572 Or, depending on your firewall configuration:
574 sudo ntpdate-debian -u
576 Note: NTP can be a little more finicky about firewalls because it uses
577 UDP vs. the more common TCP that you see with most Internet protocols.
578 Worse case, you might have to manually set the time on your development
579 box instead of using NTP.
581 Open C<root/src/books/list.tt2> and add the following lines to the
582 bottom (below the closing </table> tag):
586 <a href="[% c.uri_for('/login') %]">Login</a>
587 <a href="[% c.uri_for(c.controller.action_for('form_create')) %]">Create</a>
590 Reload your browser and you should now see a "Login" and "Create" links
591 at the bottom of the page (as mentioned earlier, you can update template
592 files without a development server reload). Click the first link to
593 return to the login page. This time you I<should> see the "You are
594 already logged in" message.
596 Finally, click the C<You can logout here> link on the C</login> page.
597 You should stay at the login page, but the message should change to "You
598 need to log in to use this application."
601 =head1 USING PASSWORD HASHES
603 In this section we increase the security of our system by converting
604 from cleartext passwords to SHA-1 password hashes that include a random
605 "salt" value to make them extremely difficult to crack with dictionary
606 and "rainbow table" attacks.
608 B<Note:> This section is optional. You can skip it and the rest of the
609 tutorial will function normally.
611 Be aware that even with the techniques shown in this section, the
612 browser still transmits the passwords in cleartext to your application.
613 We are just avoiding the I<storage> of cleartext passwords in the
614 database by using a salted SHA-1 hash. If you are concerned about
615 cleartext passwords between the browser and your application, consider
616 using SSL/TLS, made easy with the Catalyst plugin
617 L<Catalyst::Plugin:RequireSSL>.
620 =head2 Re-Run the DBIC::Schema Model Helper to Include DBIx::Class::PassphraseColumn
622 Next, we can re-run the model helper to have it include
623 L<DBIx::Class::PassphraseColumn> in all of the Result Classes it
624 generates for us. Simply use the same command we saw in Chapters 3 and
625 4, but add C<,PassphraseColumn> to the C<components> argument:
627 $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
628 create=static components=TimeStamp,PassphraseColumn dbi:SQLite:myapp.db \
629 on_connect_do="PRAGMA foreign_keys = ON"
631 If you then open one of the Result Classes, you will see that it
632 includes PassphraseColumn in the C<load_components> line. Take a look
633 at C<lib/MyApp/Schema/Result/User.pm> since that's the main class where
634 we want to use hashed and salted passwords:
636 __PACKAGE__->load_components("InflateColumn::DateTime", "TimeStamp", "PassphraseColumn");
639 =head2 Modify the "password" Column to Use PassphraseColumn
641 Open the file C<lib/MyApp/Schema/Result/User.pm> and enter the following
642 text below the "# DO NOT MODIFY THIS OR ANYTHING ABOVE!" line but above
645 # Have the 'password' column use a SHA-1 hash and 20-byte salt
646 # with RFC 2307 encoding; Generate the 'check_password" method
647 __PACKAGE__->add_columns(
649 passphrase => 'rfc2307',
650 passphrase_class => 'SaltedDigest',
652 algorithm => 'SHA-1',
655 passphrase_check_method => 'check_password',
659 This redefines the automatically generated definition for the password
660 fields at the top of the Result Class file to now use PassphraseColumn
661 logic, storing passwords in RFC 2307 format (C<passphrase> is set to
662 C<rfc2307>). C<passphrase_class> can be set to the name of any
663 C<Authen::Passphrase::*> class, such as C<SaltedDigest> to use
664 L<Authen::Passphrase::SaltedDigest>, or C<BlowfishCrypt> to use
665 L<Authen::Passphrase::BlowfishCrypt>. C<passphrase_args> is then used
666 to customize the passphrase class you selected. Here we specified the
667 digest algorithm to use as C<SHA-1> and the size of the salt to use, but
668 we could have also specified any other option the selected passphrase
672 =head2 Load Hashed Passwords in the Database
674 Next, let's create a quick script to load some hashed and salted
675 passwords into the C<password> column of our C<users> table. Open the
676 file C<set_hashed_passwords.pl> in your editor and enter the following
686 my $schema = MyApp::Schema->connect('dbi:SQLite:myapp.db');
688 my @users = $schema->resultset('User')->all;
690 foreach my $user (@users) {
691 $user->password('mypass');
695 PassphraseColumn lets us simply call C<$user->check_password($password)>
696 to see if the user has supplied the correct password, or, as we show
697 above, call C<$user->update($new_password)> to update the hashed
698 password stored for this user.
700 Then run the following command:
702 $ DBIC_TRACE=1 perl -Ilib set_hashed_passwords.pl
704 We had to use the C<-Ilib> argument to tell perl to look under the
705 C<lib> directory for our C<MyApp::Schema> model.
707 The DBIC_TRACE output should show that the update worked:
709 $ DBIC_TRACE=1 perl -Ilib set_hashed_passwords.pl
710 SELECT me.id, me.username, me.password, me.email_address,
711 me.first_name, me.last_name, me.active FROM users me:
712 UPDATE users SET password = ? WHERE ( id = ? ):
713 '{SSHA}esgz64CpHMo8pMfgIIszP13ft23z/zio04aCwNdm0wc6MDeloMUH4g==', '1'
714 UPDATE users SET password = ? WHERE ( id = ? ):
715 '{SSHA}FpGhpCJus+Ea9ne4ww8404HH+hJKW/fW+bAv1v6FuRUy2G7I2aoTRQ==', '2'
716 UPDATE users SET password = ? WHERE ( id = ? ):
717 '{SSHA}ZyGlpiHls8qFBSbHr3r5t/iqcZE602XLMbkSVRRNl6rF8imv1abQVg==', '3'
719 But we can further confirm our actions by dumping the users table:
721 $ sqlite3 myapp.db "select * from users"
722 1|test01|{SSHA}esgz64CpHMo8pMfgIIszP13ft23z/zio04aCwNdm0wc6MDeloMUH4g==|t01@na.com|Joe|Blow|1
723 2|test02|{SSHA}FpGhpCJus+Ea9ne4ww8404HH+hJKW/fW+bAv1v6FuRUy2G7I2aoTRQ==|t02@na.com|Jane|Doe|1
724 3|test03|{SSHA}ZyGlpiHls8qFBSbHr3r5t/iqcZE602XLMbkSVRRNl6rF8imv1abQVg==|t03@na.com|No|Go|0
726 As you can see, the passwords are much harder to steal from the database
727 (not only are the hashes stored, but every hash is different even though
728 the passwords are the same because of the added "salt" value). Also
729 note that this demonstrates how to use a DBIx::Class model outside of
730 your web application -- a very useful feature in many situations.
733 =head2 Enable Hashed and Salted Passwords
735 Edit C<lib/MyApp.pm> and update it to match the following text (the only
736 change is to the C<password_type> field):
738 # Configure SimpleDB Authentication
740 'Plugin::Authentication' => {
743 user_model => 'DB::User',
744 password_type => 'self_check',
749 The use of C<self_check> will cause
750 Catalyst::Plugin::Authentication::Store::DBIC to call the
751 C<check_password> method we enabled on our C<password> columns.
754 =head2 Try Out the Hashed Passwords
756 The development server should restart as soon as your save the
757 C<lib/MyApp.pm> file in the previous section. You should now be able to
758 go to L<http://localhost:3000/books/list> and login as before. When
759 done, click the "logout" link on the login page (or point your browser
760 at L<http://localhost:3000/logout>).
763 =head1 USING THE SESSION FOR FLASH
765 As discussed in the previous chapter of the tutorial, C<flash> allows
766 you to set variables in a way that is very similar to C<stash>, but it
767 will remain set across multiple requests. Once the value is read, it is
768 cleared (unless reset). Although C<flash> has nothing to do with
769 authentication, it does leverage the same session plugins. Now that
770 those plugins are enabled, let's go back and update the "delete and
771 redirect with query parameters" code seen at the end of the
772 L<Basic CRUD|Catalyst::Manual::Tutorial::04_BasicCRUD> chapter of the
773 tutorial to take advantage of C<flash>.
775 First, open C<lib/MyApp/Controller/Books.pm> and modify C<sub delete> to
776 match the following (everything after the model search line of code has
785 sub delete :Chained('object') :PathPart('delete') :Args(0) {
788 # Use the book object saved by 'object' and delete it along
789 # with related 'book_authors' entries
790 $c->stash->{object}->delete;
792 # Use 'flash' to save information across requests until it's read
793 $c->flash->{status_msg} = "Book deleted";
795 # Redirect the user back to the list page
796 $c->response->redirect($c->uri_for($self->action_for('list')));
799 Next, open C<root/src/wrapper.tt2> and update the TT code to pull from
800 flash vs. the C<status_msg> query parameter:
804 [%# Status and error messages %]
805 <span class="message">[% status_msg || c.flash.status_msg %]</span>
806 <span class="error">[% error_msg %]</span>
807 [%# This is where TT will stick all of your template's contents. -%]
809 </div><!-- end content -->
812 Although the sample above only shows the C<content> div, leave the rest
813 of the file intact -- the only change we made to replace "||
814 c.request.params.status_msg" with "c.flash.status_msg" in the
815 C<E<lt>span class="message"E<gt>> line.
820 Authenticate using the login screen and then point your browser to
821 L<http://localhost:3000/books/url_create/Test/1/4> to create an extra
822 several books. Click the "Return to list" link and delete one of the
823 "Test" books you just added. The C<flash> mechanism should retain our
824 "Book deleted" status message across the redirect.
826 B<NOTE:> While C<flash> will save information across multiple requests,
827 I<it does get cleared the first time it is read>. In general, this is
828 exactly what you want -- the C<flash> message will get displayed on the
829 next screen where it's appropriate, but it won't "keep showing up" after
830 that first time (unless you reset it). Please refer to
831 L<Catalyst::Plugin::Session> for additional information.
834 =head2 Switch To Flash-To-Stash
836 Although the use of flash above works well, the
837 C<status_msg || c.flash.status_msg> statement is a little ugly. A nice
838 alternative is to use the C<flash_to_stash> feature that automatically
839 copies the content of flash to stash. This makes your controller and
840 template code work regardless of where it was directly access, a
841 forward, or a redirect. To enable C<flash_to_stash>, you can either set
842 the value in C<lib/MyApp.pm> by changing the default
843 C<__PACKAGE__-E<gt>config> setting to something like:
847 # Disable deprecated behavior needed by old applications
848 disable_component_resolution_regex_fallback => 1,
849 'Plugin::Session' => { flash_to_stash => 1 },
852 B<or> add the following to C<myapp.conf>:
858 The C<__PACKAGE__-E<gt>config> option is probably preferable here since
859 it's not something you will want to change at runtime without it
860 possibly breaking some of your code.
862 Then edit C<root/src/wrapper.tt2> and change the C<status_msg> line to
865 <span class="message">[% status_msg %]</span>
867 Now go to L<http://localhost:3000/books/list> in your browser. Delete
868 another of the "Test" books you added in the previous step. Flash should
869 still maintain the status message across the redirect even though you
870 are no longer explicitly accessing C<c.flash>.
875 Kennedy Clark, C<hkclark@gmail.com>
877 Feel free to contact the author for any errors or suggestions, but the
878 best way to report issues is via the CPAN RT Bug system at
879 <https://rt.cpan.org/Public/Dist/Display.html?Name=Catalyst-Manual>.
881 The most recent version of the Catalyst Tutorial can be found at
882 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
884 Copyright 2006-2010, Kennedy Clark, under the
885 Creative Commons Attribution Share-Alike License Version 3.0
886 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).