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|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 user 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 user(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 user VALUES (1, 'test01', 'mypass', 't01@na.com', 'Joe', 'Blow', 1);
110 INSERT INTO user VALUES (2, 'test02', 'mypass', 't02@na.com', 'Jane', 'Doe', 1);
111 INSERT INTO user 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|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');
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::TT | 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):
232 Session::Store::FastMmap
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::FastMmap';
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> or
263 L<Session::Store::FastMmap|Catalyst::Plugin::Session::Store::FastMmap> is
264 generally a good choice if you are on Unix. If you are running on
266 L<Session::Store::File|Catalyst::Plugin::Session::Store::File>. Consult
267 L<Session::Store|Catalyst::Plugin::Session::Store> and its subclasses
268 for additional information and options (for example to use a database-
269 backed session store).
272 =head2 Configure Authentication
274 There are a variety of ways to provide configuration information to
275 L<Catalyst::Plugin::Authentication|Catalyst::Plugin::Authentication>.
277 L<Catalyst::Authentication::Realm::SimpleDB|Catalyst::Authentication::Realm::SimpleDB>
278 because it automatically sets a reasonable set of defaults for us. Open
279 C<lib/MyApp.pm> and place the following text above the call to
280 C<__PACKAGE__-E<gt>setup();>:
282 # Configure SimpleDB Authentication
283 __PACKAGE__->config->{'Plugin::Authentication'} = {
286 user_model => 'DB::User',
287 password_type => 'clear',
291 We could have placed this configuration in C<myapp.conf>, but placing
292 it in C<lib/MyApp.pm> is probably a better place since it's not likely
293 something that users of your application will want to change during
294 deployment (or you could use a mixture: leave C<class> and
295 C<user_model> defined in C<lib/MyApp.pm> as we show above, but place
296 C<password_type> in C<myapp.conf> to allow the type of password to be
297 easily modified during deployment). We will stick with putting
298 all of the authentication-related configuration in C<lib/MyApp.pm>
299 for the tutorial, but if you wish to use C<myapp.conf>, just convert
300 to the following code:
302 <Plugin::Authentication>
308 </Plugin::Authentication>
310 B<TIP:> Here is a short script that will dump the contents of
311 C<MyApp->config> to L<Config::General|Config::General> format in
314 $ CATALYST_DEBUG=0 perl -Ilib -e 'use MyApp; use Config::General;
315 Config::General->new->save_file("myapp.conf", MyApp->config);'
317 B<HOWEVER>, if you try out the command above, be sure to delete the
318 "myapp.conf" command. Otherwise, you will wind up with duplicate
321 B<NOTE:> Because we are using SimpleDB along with a database layout
322 that complies with its default assumptions: we don't need to specify
323 the names of the columns where our username and password information
324 is stored (hence, the "Simple" part of "SimpleDB"). That being said,
325 SimpleDB lets you specify that type of information if you need to.
327 C<Catalyst::Authentication::Realm::SimpleDB|Catalyst::Authentication::Realm::SimpleDB>
331 =head2 Add Login and Logout Controllers
333 Use the Catalyst create script to create a stub controller file:
335 $ script/myapp_create.pl controller Authentication
337 You could easily use multiple controller's here. For example, you could
338 have a C<User> controller for both C<login> and C<logout> actions.
339 Remember, Catalyst is designed to be very flexible, and leaves such
340 matters up to you, the designer and programmer.
342 Then open C<lib/MyApp/Controller/Authentication.pm>, locate the
343 C<sub index :Path :Args(0)> method (or C<sub index : Private> if you
344 are using an older version of Catalyst) that was automatically
345 inserted by the helpers when we created the Login controller above,
346 and remove the definition of C<sub index>. Add the following sub:
354 # global means the path to it will be /login not /authenticaton/login
355 sub login :Global :Args(0) {
358 # Get the username and password from form
359 my $username = $c->request->params->{username};
360 my $password = $c->request->params->{password};
362 # If the username and password values were found in form
363 if ($username && $password) {
364 # Attempt to log the user in
365 if ($c->authenticate({ username => $username,
366 password => $password } )) {
367 # If successful, then let them use the application
368 $c->response->redirect($c->uri_for(
369 $c->controller('Books')->action_for('list')));
372 $c->stash(error_msg => "Bad username or password.");
375 $c->stash(error_msg => "Empty username or password.");
378 # If either of above don't work out, send to the login page
379 $c->stash(template => 'login.tt2');
382 This controller fetches the C<username> and C<password> values from the
383 login form and attempts to authenticate the user. If successful, it
384 redirects the user to the book list page. If the login fails, the user
385 will stay at the login page and receive an error message. If the
386 C<username> and C<password> values are not present in the form, the
387 user will be taken to the empty login form.
389 Note that we could have used something like "C<sub default :Path>",
390 however, it is generally recommended (partly for historical reasons,
391 and partly for code clarity) only to use C<default> in
392 C<MyApp::Controller::Root>, and then mainly to generate the 404 not
393 found page for the application.
395 Instead, we are using "C<sub somename :Global :Args(0) {...}>" here to
396 specifically match the URL C</login>. C<Global> actions create URI matches
397 relative to the web root. We make the match even more specific with the
398 C<:Args(0)> action modifier -- this forces the match on I<only> C</login>,
399 not C</login/somethingelse>.
401 Next, update the corresponding method in
402 C<lib/MyApp/Controller/Logout.pm> to match:
410 sub index :Path :Args(0) {
413 # Clear the user's state
416 # Send the user to the starting point
417 $c->response->redirect($c->uri_for('/'));
420 As with the login controller, be sure to delete the
421 C<$c-E<gt>response-E<gt>body('Matched MyApp::Controller::Logout in Logout.');>
422 line of the C<sub index>.
425 =head2 Add a Login Form TT Template Page
427 Create a login form by opening C<root/src/login.tt2> and inserting:
429 [% META title = 'Login' %]
432 <form method="post" action="[% c.uri_for('/login') %]">
436 <td><input type="text" name="username" size="40" /></td>
440 <td><input type="password" name="password" size="40" /></td>
443 <td colspan="2"><input type="submit" name="submit" value="Submit" /></td>
449 =head2 Add Valid User Check
451 We need something that provides enforcement for the authentication
452 mechanism -- a I<global> mechanism that prevents users who have not
453 passed authentication from reaching any pages except the login page.
454 This is generally done via an C<auto> action/method in
455 C<lib/MyApp/Controller/Root.pm>.
457 Edit the existing C<lib/MyApp/Controller/Root.pm> class file and insert
458 the following method:
462 Check if there is a user and, if not, forward to login page
466 # Note that 'auto' runs after 'begin' but before your actions and that
467 # 'auto's "chain" (all from application path to most specific class are run)
468 # See the 'Actions' section of 'Catalyst::Manual::Intro' for more info.
472 # Allow unauthenticated users to reach the login page. This
473 # allows unauthenticated users to reach any action in the Login
474 # controller. To lock it down to a single action, we could use:
475 # if ($c->action eq $c->controller('Login')->action_for('index'))
476 # to only allow unauthenticated access to the 'index' action we
478 if ($c->controller eq $c->controller('Login')) {
482 # If a user doesn't exist, force login
483 if (!$c->user_exists) {
484 # Dump a log message to the development server debug output
485 $c->log->debug('***Root::auto User not found, forwarding to /login');
486 # Redirect the user to the login page
487 $c->response->redirect($c->uri_for('/login'));
488 # Return 0 to cancel 'post-auto' processing and prevent use of application
492 # User found, so return 1 to continue with processing after this 'auto'
497 L<Catalyst::Manual::Tutorial::03_MoreCatalystBasics/CREATE A CATALYST CONTROLLER>,
498 every C<auto> method from the application/root controller down to the
499 most specific controller will be called. By placing the
500 authentication enforcement code inside the C<auto> method of
501 C<lib/MyApp/Controller/Root.pm> (or C<lib/MyApp.pm>), it will be
502 called for I<every> request that is received by the entire
506 =head2 Displaying Content Only to Authenticated Users
508 Let's say you want to provide some information on the login page that
509 changes depending on whether the user has authenticated yet. To do
510 this, open C<root/src/login.tt2> in your editor and add the following
511 lines to the bottom of the file:
516 # This code illustrates how certain parts of the TT
517 # template will only be shown to users who have logged in
519 [% IF c.user_exists %]
520 Please Note: You are already logged in as '[% c.user.username %]'.
521 You can <a href="[% c.uri_for('/logout') %]">logout</a> here.
523 You need to log in to use this application.
526 Note that this whole block is a comment because the "#" appears
527 immediate after the "[%" (with no spaces in between). Although it
528 can be a handy way to temporarily "comment out" a whole block of
529 TT code, it's probably a little too subtle for use in "normal"
534 Although most of the code is comments, the middle few lines provide a
535 "you are already logged in" reminder if the user returns to the login
536 page after they have already authenticated. For users who have not yet
537 authenticated, a "You need to log in..." message is displayed (note the
538 use of an IF-THEN-ELSE construct in TT).
541 =head2 Try Out Authentication
543 The development server should have reloaded each time we edited one of
544 the Controllers in the previous section. Now trying going to
545 L<http://localhost:3000/books/list> and you should be redirected to the
546 login page, hitting Shift+Reload or Ctrl+Reload if necessary (the "You
547 are already logged in" message should I<not> appear -- if it does, click
548 the C<logout> button and try again). Note the C<***Root::auto User not
549 found...> debug message in the development server output. Enter username
550 C<test01> and password C<mypass>, and you should be taken to the Book
553 B<IMPORTANT NOTE:> If you are having issues with authentication on
554 Internet Explorer, be sure to check the system clocks on both your
555 server and client machines. Internet Explorer is very picky about
556 timestamps for cookies. You can quickly sync a Debian system by
557 installing the "ntpdate" package:
559 sudo aptitude -y install ntpdate
561 And then run the following command:
565 Or, depending on your firewall configuration:
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
586 to 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
598 random "salt" value to make them extremely difficult to crack 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 browser
605 still transmits the passwords in cleartext to your application. We are
606 just avoiding the I<storage> of cleartext passwords in the database by
607 using a salted SHA-1 hash. If you are concerned about cleartext passwords
608 between the browser and your application, consider using SSL/TLS, made
609 easy with the Catalyst plugin Catalyst::Plugin:RequireSSL.
612 =head2 Re-Run the DBIC::Schema Model Helper to Include DBIx::Class::EncodedColumn
614 Next, we can re-run the model helper to have it include
615 L<DBIx::Class::EncodedColumn|DBIx::Class::EncodedColumn> in all of the
616 Result Classes it generates for us. Simply use the same command we
617 saw in Chapters 3 and 4, but add C<,EncodedColumn> to the C<components>
620 $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
621 create=static components=TimeStamp,EncodedColumn 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 EncodedColumn in the C<load_components> line. Take a look at
626 C<lib/MyApp/Schema/Result/User.pm> since that's the main class where we
627 want to use hashed and salted passwords:
629 __PACKAGE__->load_components("InflateColumn::DateTime", "TimeStamp", "EncodedColumn");
632 =head2 Modify the "password" Column to Use EncodedColumn
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 10-character salt
639 # with hex encoding; Generate the 'check_password" method
640 __PACKAGE__->add_columns(
643 encode_class => 'Digest',
644 encode_args => {salt_length => 10},
645 encode_check_method => 'check_password',
649 This redefines the automatically generated definition for the password
650 fields at the top of the Result Class file to now use EncodedColumn
651 logic (C<encoded_column> is set to 1). C<encode_class> can be set to
652 either C<Digest> to use
653 L<DBIx::Class::EncodedColumn::Digest|DBIx::Class::EncodedColumn::Digest>,
654 or C<Crypt::Eksblowfish::Bcrypt> for
655 L<DBIx::Class::EncodedColumn::Crypt::Eksblowfish::Bcrypt|DBIx::Class::EncodedColumn::Crypt::Eksblowfish::Bcrypt>.
656 C<encode_args> is then used to customize the type of Digest you
657 selected. Here we only specified the size of the salt to use, but
658 we could have also modified the hashing algorithm ('SHA-256' is
659 the default) and the format to use ('base64' is the default, but
660 'hex' and 'binary' are other options). To use these, you could
661 change the C<encode_args> to something like:
663 encode_args => {algorithm => 'SHA-1',
668 =head2 Load Hashed Passwords in the Database
670 Next, let's create a quick script to load some hashed and salted passwords
671 into the C<password> column of our C<users> table. Open the file
672 C<set_hashed_passwords.pl> in your editor and enter the following text:
681 my $schema = MyApp::Schema->connect('dbi:SQLite:myapp.db');
683 my @users = $schema->resultset('User')->all;
685 foreach my $user (@users) {
686 $user->password('mypass');
690 EncodedColumn lets us simple call C<$user->check_password($password)>
691 to see if the user has supplied the correct password, or, as we show
692 above, call C<$user->update($new_password)> to update the hashed
693 password stored for this user.
695 Then run the following command:
697 $ DBIC_TRACE=1 perl -Ilib set_hashed_passwords.pl
699 We had to use the C<-Ilib> argument to tell perl to look under the
700 C<lib> directory for our C<MyApp::Schema> model.
702 The DBIC_TRACE output should show that the update worked:
704 $ DBIC_TRACE=1 perl -Ilib set_hashed_passwords.pl
705 SELECT me.id, me.username, me.password, me.email_address,
706 me.first_name, me.last_name, me.active FROM user me:
707 UPDATE user SET password = ? WHERE ( id = ? ):
708 'oXiyAcGOjowz7ISUhpIm1IrS8AxSZ9r4jNjpX9VnVeQmN6GRtRKTz', '1'
709 UPDATE user SET password = ? WHERE ( id = ? ):
710 'PmyEPrkB8EGwvaF/DvJm7LIfxoZARjv8ygFIR7pc1gEA1OfwHGNzs', '2'
711 UPDATE user SET password = ? WHERE ( id = ? ):
712 'h7CS1Fm9UCs4hjcbu2im0HumaHCJUq4Uriac+SQgdUMUfFSoOrz3c', '3'
714 But we can further confirm our actions by dumping the users table:
716 $ sqlite3 myapp.db "select * from user"
717 1|test01|38d3974fa9e9263099f7bc2574284b2f55473a9bM=fwpX2NR8|t01@na.com|Joe|Blow|1
718 2|test02|6ed8586587e53e0d7509b1cfed5df08feadc68cbMJlnPyPt0I|t02@na.com|Jane|Doe|1
719 3|test03|af929a151340c6aed4d54d7e2651795d1ad2e2f7UW8dHoGv9z|t03@na.com|No|Go|0
721 As you can see, the passwords are much harder to steal from the
722 database (not only are the hashes stored, but every hash is different
723 even though the passwords are the same because of the added "salt"
724 value). Also note that this demonstrates how to use a DBIx::Class
725 model outside of your web application -- a very useful feature in many
729 =head2 Enable Hashed and Salted Passwords
731 Edit C<lib/MyApp.pm> and update it to match the following text (the
732 only change is to the C<password_type> field):
734 # Configure SimpleDB Authentication
735 __PACKAGE__->config->{'Plugin::Authentication'} = {
738 user_model => 'DB::User',
739 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
762 is 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 L<Basic
766 CRUD|Catalyst::Manual::Tutorial::04_BasicCRUD> chapter of the tutorial to
767 take advantage of C<flash>.
769 First, open C<lib/MyApp/Controller/Books.pm> and modify C<sub delete>
770 to match the following (everything after the model search line of code
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
807 rest 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<< <span class="message"> >> 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
823 the next screen where it's appropriate, but it won't "keep showing up"
824 after that first time (unless you reset it). Please refer to
825 L<Catalyst::Plugin::Session|Catalyst::Plugin::Session> for additional
829 =head2 Switch To Flash-To-Stash
831 Although the a use of flash above works well, the
832 C<status_msg || c.flash.status_msg> statement is a little ugly. A nice
833 alternative is to use the C<flash_to_stash> feature that automatically
834 copies the content of flash to stash. This makes your controller
835 and template code work regardless of where it was directly access, a
836 forward, or a redirect. To enable C<flash_to_stash>, you can either
837 set the value in C<lib/MyApp.pm> by changing the default
838 C<__PACKAGE__-E<gt>config> setting to something like:
842 # Disable deprecated behavior needed by old applications
843 disable_component_resolution_regex_fallback => 1,
844 session => { flash_to_stash => 1 },
847 B<or> add the following to C<myapp.conf>:
853 The C<__PACKAGE__-E<gt>config> option is probably preferable here
854 since it's not something you will want to change at runtime without it
855 possibly breaking some of your code.
857 Then edit C<root/src/wrapper.tt2> and change the C<status_msg> line
858 to match the following:
860 <span class="message">[% status_msg %]</span>
862 Now go to L<http://localhost:3000/books/list> in your browser. Delete
863 another of the "Test" books you added in the previous step. Flash should
864 still maintain the status message across the redirect even though you
865 are no longer explicitly accessing C<c.flash>.
870 Kennedy Clark, C<hkclark@gmail.com>
872 Please report any errors, issues or suggestions to the author. The
873 most recent version of the Catalyst Tutorial can be found at
874 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
876 Copyright 2006-2008, Kennedy Clark, under Creative Commons License
877 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).