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
63 This chapter of the tutorial is divided into two main sections: 1) basic,
64 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 opening
82 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 C<create=static>
128 option on the DBIC model helper to do most of the work for us:
130 $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
131 create=static components=TimeStamp dbi:SQLite:myapp.db \
132 on_connect_do="PRAGMA foreign_keys = ON"
133 exists "/root/dev/MyApp/script/../lib/MyApp/Model"
134 exists "/root/dev/MyApp/script/../t"
135 Dumping manual schema for MyApp::Schema to directory /root/dev/MyApp/script/../lib ...
136 Schema dump completed.
137 exists "/root/dev/MyApp/script/../lib/MyApp/Model/DB.pm"
139 $ ls lib/MyApp/Schema/Result
140 Author.pm BookAuthor.pm Book.pm Role.pm User.pm UserRole.pm
142 Notice how the helper has added three new table-specific Result Source
143 files to the C<lib/MyApp/Schema/Result> directory. And, more
144 importantly, even if there were changes to the existing result source
145 files, those changes would have only been written above the C<# DO NOT
146 MODIFY THIS OR ANYTHING ABOVE!> comment and your hand-edited
147 enhancements would have been preserved.
149 Speaking of "hand-editted enhancements," we should now add the
150 C<many_to_many> relationship information to the User Result Source file.
151 As with the Book, BookAuthor, and Author files in
152 L<Chapter 3|Catalyst::Manual::Tutorial::03_MoreCatalystBasics>,
153 L<DBIx::Class::Schema::Loader> has
154 automatically created the C<has_many> and C<belongs_to> relationships
155 for the new User, UserRole, and Role tables. However, as a convenience
156 for mapping Users to their assigned roles (see
157 L<Chapter 6|Catalyst::Manual::Tutorial::06_Authorization>), we will
158 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
180 of 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
182 new table information.
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"
213 by 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
247 C<Authentication> plugin. You B<do not need> to specify a particular
248 Authentication::Store or Authentication::Credential plugin. Instead,
249 indicate the Store and Credential you want to use in your application
250 configuration (see below).
252 Make sure you include the additional plugins as new dependencies in
253 the 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> is
263 generally a good choice if you are on Unix. If you are running on
265 L<Session::Store::File|Catalyst::Plugin::Session::Store::File> is fine. Consult
266 L<Session::Store|Catalyst::Plugin::Session::Store> and its subclasses
267 for additional information and options (for example to use a database-
268 backed session store).
271 =head2 Configure Authentication
273 There are a variety of ways to provide configuration information to
274 L<Catalyst::Plugin::Authentication>.
276 L<Catalyst::Authentication::Realm::SimpleDB>
277 because it automatically sets a reasonable set of defaults for us. Open
278 C<lib/MyApp.pm> and place the following text above the call to
279 C<__PACKAGE__-E<gt>setup();>:
281 # Configure SimpleDB Authentication
283 'Plugin::Authentication' => {
286 user_model => 'DB::User',
287 password_type => 'clear',
292 We could have placed this configuration in C<myapp.conf>, but placing
293 it in C<lib/MyApp.pm> is probably a better place since it's not likely
294 something that users of your application will want to change during
295 deployment (or you could use a mixture: leave C<class> and
296 C<user_model> defined in C<lib/MyApp.pm> as we show above, but place
297 C<password_type> in C<myapp.conf> to allow the type of password to be
298 easily modified during deployment). We will stick with putting
299 all of the authentication-related configuration in C<lib/MyApp.pm>
300 for the tutorial, but if you wish to use C<myapp.conf>, just convert
301 to the following code:
303 <Plugin::Authentication>
309 </Plugin::Authentication>
311 B<TIP:> Here is a short script that will dump the contents of
312 C<MyApp->config> to L<Config::General> format in
315 $ CATALYST_DEBUG=0 perl -Ilib -e 'use MyApp; use Config::General;
316 Config::General->new->save_file("myapp.conf", MyApp->config);'
318 B<HOWEVER>, if you try out the command above, be sure to delete the
319 "myapp.conf" command. Otherwise, you will wind up with duplicate
322 B<NOTE:> Because we are using SimpleDB along with a database layout
323 that complies with its default assumptions: we don't need to specify
324 the names of the columns where our username and password information
325 is stored (hence, the "Simple" part of "SimpleDB"). That being said,
326 SimpleDB lets you specify that type of information if you need to.
328 C<Catalyst::Authentication::Realm::SimpleDB|Catalyst::Authentication::Realm::SimpleDB>
332 =head2 Add Login and Logout Controllers
334 Use the Catalyst create script to create two stub controller files:
336 $ script/myapp_create.pl controller Login
337 $ script/myapp_create.pl controller Logout
339 You could easily use a single controller here. For example, you could
340 have a C<User> controller with both C<login> and C<logout> actions.
341 Remember, Catalyst is designed to be very flexible, and leaves such
342 matters up to you, the designer and programmer.
344 Then open C<lib/MyApp/Controller/Login.pm>, locate the
345 C<sub index :Path :Args(0)> method (or C<sub index : Private> if you
346 are using an older version of Catalyst) that was automatically
347 inserted by the helpers when we created the Login controller above,
348 and update the definition of 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 $c->stash(template => 'login.tt2');
386 Be sure to remove the
387 C<$c-E<gt>response-E<gt>body('Matched MyApp::Controller::Login in Login.');>
388 line of the C<sub index>.
390 This controller fetches the C<username> and C<password> values from the
391 login form and attempts to authenticate the user. If successful, it
392 redirects the user to the book list page. If the login fails, the user
393 will stay at the login page and receive an error message. If the
394 C<username> and C<password> values are not present in the form, the
395 user will be taken to the empty login form.
397 Note that we could have used something like "C<sub default :Path>",
398 however, it is generally recommended (partly for historical reasons,
399 and partly for code clarity) only to use C<default> in
400 C<MyApp::Controller::Root>, and then mainly to generate the 404 not
401 found page for the application.
403 Instead, we are using "C<sub somename :Path :Args(0) {...}>" here to
404 specifically match the URL C</login>. C<Path> actions (aka, "literal
405 actions") create URI matches relative to the namespace of the
406 controller where they are defined. Although C<Path> supports
407 arguments that allow relative and absolute paths to be defined, here
408 we use an empty C<Path> definition to match on just the name of the
409 controller itself. The method name, C<index>, is arbitrary. We make
410 the match even more specific with the C<:Args(0)> action modifier --
411 this forces the match on I<only> C</login>, not
412 C</login/somethingelse>.
414 Next, update the corresponding method in
415 C<lib/MyApp/Controller/Logout.pm> to match:
423 sub index :Path :Args(0) {
426 # Clear the user's state
429 # Send the user to the starting point
430 $c->response->redirect($c->uri_for('/'));
433 As with the login controller, be sure to delete the
434 C<$c-E<gt>response-E<gt>body('Matched MyApp::Controller::Logout in Logout.');>
435 line of the C<sub index>.
438 =head2 Add a Login Form TT Template Page
440 Create a login form by opening C<root/src/login.tt2> and inserting:
442 [% META title = 'Login' %]
445 <form method="post" action="[% c.uri_for('/login') %]">
449 <td><input type="text" name="username" size="40" /></td>
453 <td><input type="password" name="password" size="40" /></td>
456 <td colspan="2"><input type="submit" name="submit" value="Submit" /></td>
462 =head2 Add Valid User Check
464 We need something that provides enforcement for the authentication
465 mechanism -- a I<global> mechanism that prevents users who have not
466 passed authentication from reaching any pages except the login page.
467 This is generally done via an C<auto> action/method in
468 C<lib/MyApp/Controller/Root.pm>.
470 Edit the existing C<lib/MyApp/Controller/Root.pm> class file and insert
471 the following method:
475 Check if there is a user and, if not, forward to login page
479 # Note that 'auto' runs after 'begin' but before your actions and that
480 # 'auto's "chain" (all from application path to most specific class are run)
481 # See the 'Actions' section of 'Catalyst::Manual::Intro' for more info.
485 # Allow unauthenticated users to reach the login page. This
486 # allows unauthenticated users to reach any action in the Login
487 # controller. To lock it down to a single action, we could use:
488 # if ($c->action eq $c->controller('Login')->action_for('index'))
489 # to only allow unauthenticated access to the 'index' action we
491 if ($c->controller eq $c->controller('Login')) {
495 # If a user doesn't exist, force login
496 if (!$c->user_exists) {
497 # Dump a log message to the development server debug output
498 $c->log->debug('***Root::auto User not found, forwarding to /login');
499 # Redirect the user to the login page
500 $c->response->redirect($c->uri_for('/login'));
501 # Return 0 to cancel 'post-auto' processing and prevent use of application
505 # User found, so return 1 to continue with processing after this 'auto'
510 L<Catalyst::Manual::Tutorial::03_MoreCatalystBasics/CREATE A CATALYST CONTROLLER>,
511 every C<auto> method from the application/root controller down to the
512 most specific controller will be called. By placing the
513 authentication enforcement code inside the C<auto> method of
514 C<lib/MyApp/Controller/Root.pm> (or C<lib/MyApp.pm>), it will be
515 called for I<every> request that is received by the entire
519 =head2 Displaying Content Only to Authenticated Users
521 Let's say you want to provide some information on the login page that
522 changes depending on whether the user has authenticated yet. To do
523 this, open C<root/src/login.tt2> in your editor and add the following
524 lines to the bottom of the file:
529 # This code illustrates how certain parts of the TT
530 # template will only be shown to users who have logged in
532 [% IF c.user_exists %]
533 Please Note: You are already logged in as '[% c.user.username %]'.
534 You can <a href="[% c.uri_for('/logout') %]">logout</a> here.
536 You need to log in to use this application.
539 Note that this whole block is a comment because the "#" appears
540 immediate after the "[%" (with no spaces in between). Although it
541 can be a handy way to temporarily "comment out" a whole block of
542 TT code, it's probably a little too subtle for use in "normal"
547 Although most of the code is comments, the middle few lines provide a
548 "you are already logged in" reminder if the user returns to the login
549 page after they have already authenticated. For users who have not yet
550 authenticated, a "You need to log in..." message is displayed (note the
551 use of an IF-THEN-ELSE construct in TT).
554 =head2 Try Out Authentication
556 The development server should have reloaded each time we edited one of
557 the Controllers in the previous section. Now try going to
558 L<http://localhost:3000/books/list> and you should be redirected to the
559 login page, hitting Shift+Reload or Ctrl+Reload if necessary (the "You
560 are already logged in" message should I<not> appear -- if it does, click
561 the C<logout> button and try again). Note the C<***Root::auto User not
562 found...> debug message in the development server output. Enter username
563 C<test01> and password C<mypass>, and you should be taken to the Book
566 B<IMPORTANT NOTE:> If you are having issues with authentication on
567 Internet Explorer, be sure to check the system clocks on both your
568 server and client machines. Internet Explorer is very picky about
569 timestamps for cookies. You can quickly sync a Debian system by
570 installing the "ntpdate" package:
572 sudo aptitude -y install ntpdate
574 And then run the following command:
578 Or, depending on your firewall configuration:
580 sudo ntpdate-debian -u
582 Note: NTP can be a little more finicky about firewalls because it uses
583 UDP vs. the more common TCP that you see with most Internet protocols.
584 Worse case, you might have to manually set the time on your development
585 box instead of using NTP.
587 Open C<root/src/books/list.tt2> and add the following lines to the
588 bottom (below the closing </table> tag):
592 <a href="[% c.uri_for('/login') %]">Login</a>
593 <a href="[% c.uri_for(c.controller.action_for('form_create')) %]">Create</a>
596 Reload your browser and you should now see a "Login" and "Create" links
597 at the bottom of the page (as mentioned earlier, you can update template
598 files without a development server reload). Click the first link
599 to return to the login page. This time you I<should> see the "You are
600 already logged in" message.
602 Finally, click the C<You can logout here> link on the C</login> page.
603 You should stay at the login page, but the message should change to "You
604 need to log in to use this application."
607 =head1 USING PASSWORD HASHES
609 In this section we increase the security of our system by converting
610 from cleartext passwords to SHA-1 password hashes that include a
611 random "salt" value to make them extremely difficult to crack with
612 dictionary and "rainbow table" attacks.
614 B<Note:> This section is optional. You can skip it and the rest of the
615 tutorial will function normally.
617 Be aware that even with the techniques shown in this section, the browser
618 still transmits the passwords in cleartext to your application. We are
619 just avoiding the I<storage> of cleartext passwords in the database by
620 using a salted SHA-1 hash. If you are concerned about cleartext passwords
621 between the browser and your application, consider using SSL/TLS, made
622 easy with the Catalyst plugin Catalyst::Plugin:RequireSSL.
625 =head2 Re-Run the DBIC::Schema Model Helper to Include DBIx::Class::PassphraseColumn
627 Next, we can re-run the model helper to have it include
628 L<DBIx::Class::PassphraseColumn> in all of the Result Classes it generates for
629 us. Simply use the same command we saw in Chapters 3 and 4, but add
630 C<,PassphraseColumn> to the C<components> argument:
632 $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
633 create=static components=TimeStamp,PassphraseColumn dbi:SQLite:myapp.db \
634 on_connect_do="PRAGMA foreign_keys = ON"
636 If you then open one of the Result Classes, you will see that it
637 includes PassphraseColumn in the C<load_components> line. Take a look at
638 C<lib/MyApp/Schema/Result/User.pm> since that's the main class where we
639 want to use hashed and salted passwords:
641 __PACKAGE__->load_components("InflateColumn::DateTime", "TimeStamp", "PassphraseColumn");
644 =head2 Modify the "password" Column to Use PassphraseColumn
646 Open the file C<lib/MyApp/Schema/Result/User.pm> and enter the following
647 text below the "# DO NOT MODIFY THIS OR ANYTHING ABOVE!" line but above
650 # Have the 'password' column use a SHA-1 hash and 20-byte salt
651 # with RFC 2307 encoding; Generate the 'check_password" method
652 __PACKAGE__->add_columns(
654 passphrase => 'rfc2307',
655 passphrase_class => 'SaltedDigest',
657 algorithm => 'SHA-1',
660 passphrase_check_method => 'check_password',
664 This redefines the automatically generated definition for the password fields at
665 the top of the Result Class file to now use PassphraseColumn logic, storing
666 passwords in RFC 2307 format (C<passphrase> is set to C<rfc2307>).
667 C<passphrase_class> can be set to the name of any C<Authen::Passphrase::*>
668 class, such as C<SaltedDigest> to use L<Authen::Passphrase::SaltedDigest>, or
669 C<BlowfishCrypt> to use L<Authen::Passphrase::BlowfishCrypt>.
670 C<passphrase_args> is then used to customize the passphrase class you
671 selected. Here we specified the digest algorithm to use as C<SHA-1> and the size
672 of the salt to use, but we could have also specified any other option the
673 selected passphrase class supports.
675 =head2 Load Hashed Passwords in the Database
677 Next, let's create a quick script to load some hashed and salted passwords
678 into the C<password> column of our C<users> table. Open the file
679 C<set_hashed_passwords.pl> in your editor and enter the following text:
688 my $schema = MyApp::Schema->connect('dbi:SQLite:myapp.db');
690 my @users = $schema->resultset('User')->all;
692 foreach my $user (@users) {
693 $user->password('mypass');
697 PassphraseColumn lets us simply call C<$user->check_password($password)>
698 to see if the user has supplied the correct password, or, as we show
699 above, call C<$user->update($new_password)> to update the hashed
700 password stored for this user.
702 Then run the following command:
704 $ DBIC_TRACE=1 perl -Ilib set_hashed_passwords.pl
706 We had to use the C<-Ilib> argument to tell perl to look under the
707 C<lib> directory for our C<MyApp::Schema> model.
709 The DBIC_TRACE output should show that the update worked:
711 $ DBIC_TRACE=1 perl -Ilib set_hashed_passwords.pl
712 SELECT me.id, me.username, me.password, me.email_address,
713 me.first_name, me.last_name, me.active FROM users me:
714 UPDATE users SET password = ? WHERE ( id = ? ):
715 '{SSHA}esgz64CpHMo8pMfgIIszP13ft23z/zio04aCwNdm0wc6MDeloMUH4g==', '1'
716 UPDATE users SET password = ? WHERE ( id = ? ):
717 '{SSHA}FpGhpCJus+Ea9ne4ww8404HH+hJKW/fW+bAv1v6FuRUy2G7I2aoTRQ==', '2'
718 UPDATE users SET password = ? WHERE ( id = ? ):
719 '{SSHA}ZyGlpiHls8qFBSbHr3r5t/iqcZE602XLMbkSVRRNl6rF8imv1abQVg==', '3'
721 But we can further confirm our actions by dumping the users table:
723 $ sqlite3 myapp.db "select * from users"
724 1|test01|{SSHA}esgz64CpHMo8pMfgIIszP13ft23z/zio04aCwNdm0wc6MDeloMUH4g==|t01@na.com|Joe|Blow|1
725 2|test02|{SSHA}FpGhpCJus+Ea9ne4ww8404HH+hJKW/fW+bAv1v6FuRUy2G7I2aoTRQ==|t02@na.com|Jane|Doe|1
726 3|test03|{SSHA}ZyGlpiHls8qFBSbHr3r5t/iqcZE602XLMbkSVRRNl6rF8imv1abQVg==|t03@na.com|No|Go|0
728 As you can see, the passwords are much harder to steal from the
729 database (not only are the hashes stored, but every hash is different
730 even though the passwords are the same because of the added "salt"
731 value). Also note that this demonstrates how to use a DBIx::Class
732 model outside of your web application -- a very useful feature in many
736 =head2 Enable Hashed and Salted Passwords
738 Edit C<lib/MyApp.pm> and update it to match the following text (the
739 only change is to the C<password_type> field):
741 # Configure SimpleDB Authentication
743 'Plugin::Authentication' => {
746 user_model => 'DB::User',
747 password_type => 'self_check',
752 The use of C<self_check> will cause
753 Catalyst::Plugin::Authentication::Store::DBIC to call the
754 C<check_password> method we enabled on our C<password> columns.
757 =head2 Try Out the Hashed Passwords
759 The development server should restart as soon as your save the
760 C<lib/MyApp.pm> file in the previous section. You should now be able to
761 go to L<http://localhost:3000/books/list> and login as before. When
762 done, click the "logout" link on the login page (or point your browser
763 at L<http://localhost:3000/logout>).
766 =head1 USING THE SESSION FOR FLASH
768 As discussed in the previous chapter of the tutorial, C<flash> allows
769 you to set variables in a way that is very similar to C<stash>, but it
770 will remain set across multiple requests. Once the value is read, it
771 is cleared (unless reset). Although C<flash> has nothing to do with
772 authentication, it does leverage the same session plugins. Now that
773 those plugins are enabled, let's go back and update the "delete and
774 redirect with query parameters" code seen at the end of the L<Basic
775 CRUD|Catalyst::Manual::Tutorial::04_BasicCRUD> chapter of the tutorial to
776 take advantage of C<flash>.
778 First, open C<lib/MyApp/Controller/Books.pm> and modify C<sub delete>
779 to match the following (everything after the model search line of code
788 sub delete :Chained('object') :PathPart('delete') :Args(0) {
791 # Use the book object saved by 'object' and delete it along
792 # with related 'book_authors' entries
793 $c->stash->{object}->delete;
795 # Use 'flash' to save information across requests until it's read
796 $c->flash->{status_msg} = "Book deleted";
798 # Redirect the user back to the list page
799 $c->response->redirect($c->uri_for($self->action_for('list')));
802 Next, open C<root/src/wrapper.tt2> and update the TT code to pull from
803 flash vs. the C<status_msg> query parameter:
807 [%# Status and error messages %]
808 <span class="message">[% status_msg || c.flash.status_msg %]</span>
809 <span class="error">[% error_msg %]</span>
810 [%# This is where TT will stick all of your template's contents. -%]
812 </div><!-- end content -->
815 Although the sample above only shows the C<content> div, leave the
816 rest of the file intact -- the only change we made to replace
817 "|| c.request.params.status_msg" with "c.flash.status_msg" in the
818 C<< <span class="message"> >> line.
823 Authenticate using the login screen and then point your browser to
824 L<http://localhost:3000/books/url_create/Test/1/4> to create an extra
825 several books. Click the "Return to list" link and delete one of the
826 "Test" books you just added. The C<flash> mechanism should retain our
827 "Book deleted" status message across the redirect.
829 B<NOTE:> While C<flash> will save information across multiple requests,
830 I<it does get cleared the first time it is read>. In general, this is
831 exactly what you want -- the C<flash> message will get displayed on
832 the next screen where it's appropriate, but it won't "keep showing up"
833 after that first time (unless you reset it). Please refer to
834 L<Catalyst::Plugin::Session> for additional
838 =head2 Switch To Flash-To-Stash
840 Although the a use of flash above works well, the
841 C<status_msg || c.flash.status_msg> statement is a little ugly. A nice
842 alternative is to use the C<flash_to_stash> feature that automatically
843 copies the content of flash to stash. This makes your controller
844 and template code work regardless of where it was directly access, a
845 forward, or a redirect. To enable C<flash_to_stash>, you can either
846 set the value in C<lib/MyApp.pm> by changing the default
847 C<__PACKAGE__-E<gt>config> setting to something like:
851 # Disable deprecated behavior needed by old applications
852 disable_component_resolution_regex_fallback => 1,
853 'Plugin::Session' => { flash_to_stash => 1 },
856 B<or> add the following to C<myapp.conf>:
862 The C<__PACKAGE__-E<gt>config> option is probably preferable here
863 since it's not something you will want to change at runtime without it
864 possibly breaking some of your code.
866 Then edit C<root/src/wrapper.tt2> and change the C<status_msg> line
867 to match the following:
869 <span class="message">[% status_msg %]</span>
871 Now go to L<http://localhost:3000/books/list> in your browser. Delete
872 another of the "Test" books you added in the previous step. Flash should
873 still maintain the status message across the redirect even though you
874 are no longer explicitly accessing C<c.flash>.
879 Kennedy Clark, C<hkclark@gmail.com>
881 Feel free to contact the author for any errors or suggestions, but the
882 best way to report issues is via the CPAN RT Bug system at
883 <https://rt.cpan.org/Public/Dist/Display.html?Name=Catalyst-Manual>.
885 The most recent version of the Catalyst Tutorial can be found at
886 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
888 Copyright 2006-2010, Kennedy Clark, under the
889 Creative Commons Attribution Share-Alike License Version 3.0
890 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).