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 Source code for the tutorial in included in the F</root/Final> directory
67 of the Tutorial Virtual machine (one subdirectory per chapter). There
68 are also instructions for downloading the code in
69 L<Catalyst::Manual::Tutorial::01_Intro>.
72 =head1 BASIC AUTHENTICATION
74 This section explores how to add authentication logic to a Catalyst
78 =head2 Add Users and Roles to the Database
80 First, we add both user and role information to the database (we will
81 add the role information here although it will not be used until the
82 authorization section, Chapter 6). Create a new SQL script file by
83 opening C<myapp02.sql> in your editor and insert:
86 -- Add users and role tables, along with a many-to-many join table
88 PRAGMA foreign_keys = ON;
90 id INTEGER PRIMARY KEY,
99 id INTEGER PRIMARY KEY,
102 CREATE TABLE user_role (
103 user_id INTEGER REFERENCES users(id) ON DELETE CASCADE ON UPDATE CASCADE,
104 role_id INTEGER REFERENCES role(id) ON DELETE CASCADE ON UPDATE CASCADE,
105 PRIMARY KEY (user_id, role_id)
108 -- Load up some initial test data
110 INSERT INTO users VALUES (1, 'test01', 'mypass', 't01@na.com', 'Joe', 'Blow', 1);
111 INSERT INTO users VALUES (2, 'test02', 'mypass', 't02@na.com', 'Jane', 'Doe', 1);
112 INSERT INTO users VALUES (3, 'test03', 'mypass', 't03@na.com', 'No', 'Go', 0);
113 INSERT INTO role VALUES (1, 'user');
114 INSERT INTO role VALUES (2, 'admin');
115 INSERT INTO user_role VALUES (1, 1);
116 INSERT INTO user_role VALUES (1, 2);
117 INSERT INTO user_role VALUES (2, 1);
118 INSERT INTO user_role VALUES (3, 1);
120 Then load this into the C<myapp.db> database with the following command:
122 $ sqlite3 myapp.db < myapp02.sql
125 =head2 Add User and Role Information to DBIC Schema
127 Although we could manually edit the DBIC schema information to include
128 the new tables added in the previous step, let's use the
129 C<create=static> option on the DBIC model helper to do most of the work
132 $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
133 create=static components=TimeStamp dbi:SQLite:myapp.db \
134 on_connect_do="PRAGMA foreign_keys = ON"
135 exists "/root/dev/MyApp/script/../lib/MyApp/Model"
136 exists "/root/dev/MyApp/script/../t"
137 Dumping manual schema for MyApp::Schema to directory /root/dev/MyApp/script/../lib ...
138 Schema dump completed.
139 exists "/root/dev/MyApp/script/../lib/MyApp/Model/DB.pm"
141 $ ls lib/MyApp/Schema/Result
142 Author.pm BookAuthor.pm Book.pm Role.pm User.pm UserRole.pm
144 Notice how the helper has added three new table-specific Result Source
145 files to the C<lib/MyApp/Schema/Result> directory. And, more
146 importantly, even if there were changes to the existing result source
147 files, those changes would have only been written above the
148 C<# DO NOT MODIFY THIS OR ANYTHING ABOVE!> comment and your hand-edited
149 enhancements would have been preserved.
151 Speaking of "hand-edited enhancements," we should now add the
152 C<many_to_many> relationship information to the User Result Source file.
153 As with the Book, BookAuthor, and Author files in
154 L<Chapter 3|Catalyst::Manual::Tutorial::03_MoreCatalystBasics>,
155 L<DBIx::Class::Schema::Loader> has automatically created the C<has_many>
156 and C<belongs_to> relationships for the new User, UserRole, and Role
157 tables. However, as a convenience for mapping Users to their assigned
158 roles (see L<Chapter 6|Catalyst::Manual::Tutorial::06_Authorization>),
159 we will also manually add a C<many_to_many> relationship. Edit
160 C<lib/MyApp/Schema/Result/User.pm> add the following information between
161 the C<# DO NOT MODIFY THIS OR ANYTHING ABOVE!> comment and the closing
166 # 1) Name of relationship, DBIC will create accessor with this name
167 # 2) Name of has_many() relationship this many_to_many() is shortcut for
168 # 3) Name of belongs_to() relationship in model class of has_many() above
169 # You must already have the has_many() defined to use a many_to_many().
170 __PACKAGE__->many_to_many(roles => 'user_roles', 'role');
172 The code for this update is obviously very similar to the edits we made
173 to the C<Book> and C<Author> classes created in
174 L<Chapter 3|Catalyst::Manual::Tutorial::03_MoreCatalystBasics> with one
175 exception: we only defined the C<many_to_many> relationship in one
176 direction. Whereas we felt that we would want to map Authors to Books
177 B<AND> Books to Authors, here we are only adding the convenience
178 C<many_to_many> in the Users to Roles direction.
180 Note that we do not need to make any change to the
181 C<lib/MyApp/Schema.pm> schema file. It simply tells DBIC to load all of
182 the Result Class and ResultSet Class files it finds below the
183 C<lib/MyApp/Schema> directory, so it will automatically pick up our new
187 =head2 Sanity-Check of the Development Server Reload
189 We aren't ready to try out the authentication just yet; we only want to
190 do a quick check to be sure our model loads correctly. Assuming that you
191 are following along and using the "-r" option on C<myapp_server.pl>,
192 then the development server should automatically reload (if not, press
193 C<Ctrl-C> to break out of the server if it's running and then enter
194 C<script/myapp_server.pl> to start it). Look for the three new model
195 objects in the startup debug output:
198 .-------------------------------------------------------------------+----------.
200 +-------------------------------------------------------------------+----------+
201 | MyApp::Controller::Books | instance |
202 | MyApp::Controller::Root | instance |
203 | MyApp::Model::DB | instance |
204 | MyApp::Model::DB::Author | class |
205 | MyApp::Model::DB::Book | class |
206 | MyApp::Model::DB::BookAuthor | class |
207 | MyApp::Model::DB::Role | class |
208 | MyApp::Model::DB::User | class |
209 | MyApp::Model::DB::UserRole | class |
210 | MyApp::View::HTML | instance |
211 '-------------------------------------------------------------------+----------'
214 Again, notice that your "Result Class" classes have been "re-loaded" by
215 Catalyst under C<MyApp::Model>.
218 =head2 Include Authentication and Session Plugins
220 Edit C<lib/MyApp.pm> and update it as follows (everything below
221 C<StackTrace> is new):
235 Session::State::Cookie
238 B<Note:> As discussed in
239 L<Chapter 3|Catalyst::Manual::Tutorial::03_MoreCatalystBasics>,
240 different versions of C<Catalyst::Devel> have used a variety of methods
241 to load the plugins, but we are going to use the current Catalyst 5.9
242 practice of putting them on the C<use Catalyst> line.
244 The C<Authentication> plugin supports Authentication while the
245 C<Session> plugins are required to maintain state across multiple HTTP
248 Note that the only required Authentication class is the main one. This
249 is a change that occurred in version 0.09999_01 of the
250 L<Authentication|Catalyst::Plugin::Authentication> plugin. You
251 B<do not need> to specify a particular
252 L<Authentication::Store|Catalyst::Authentication::Store> or
253 C<Authentication::Credential> you want to use. Instead, indicate the
254 Store and Credential you want to use in your application configuration
257 Make sure you include the additional plugins as new dependencies in the
258 Makefile.PL file something like this:
260 requires 'Catalyst::Plugin::Authentication';
261 requires 'Catalyst::Plugin::Session';
262 requires 'Catalyst::Plugin::Session::Store::File';
263 requires 'Catalyst::Plugin::Session::State::Cookie';
265 Note that there are several options for
266 L<Session::Store|Catalyst::Plugin::Session::Store>.
267 L<Session::Store::Memcached|Catalyst::Plugin::Session::Store::Memcached>
268 is generally a good choice if you are on Unix. If you are running on
269 Windows L<Session::Store::File|Catalyst::Plugin::Session::Store::File>
270 is fine. Consult L<Session::Store|Catalyst::Plugin::Session::Store> and
271 its subclasses for additional information and options (for example to
272 use a database-backed session store).
275 =head2 Configure Authentication
277 There are a variety of ways to provide configuration information to
278 L<Catalyst::Plugin::Authentication>. Here we will use
279 L<Catalyst::Authentication::Realm::SimpleDB> because it automatically
280 sets a reasonable set of defaults for us. (Note: the C<SimpleDB> here
281 has nothing to do with the SimpleDB offered in Amazon's web services
282 offerings -- here we are only talking about a "simple" way to use your
283 DB as an authentication backend.) Open C<lib/MyApp.pm> and place the
284 following text above the call to C<__PACKAGE__-E<gt>setup();>:
286 # Configure SimpleDB Authentication
288 'Plugin::Authentication' => {
291 user_model => 'DB::User',
292 password_type => 'clear',
297 We could have placed this configuration in C<myapp.conf>, but placing it
298 in C<lib/MyApp.pm> is probably a better place since it's not likely
299 something that users of your application will want to change during
300 deployment (or you could use a mixture: leave C<class> and C<user_model>
301 defined in C<lib/MyApp.pm> as we show above, but place C<password_type>
302 in C<myapp.conf> to allow the type of password to be easily modified
303 during deployment). We will stick with putting all of the
304 authentication-related configuration in C<lib/MyApp.pm> for the
305 tutorial, but if you wish to use C<myapp.conf>, just convert to the
308 <Plugin::Authentication>
314 </Plugin::Authentication>
316 B<TIP:> Here is a short script that will dump the contents of
317 C<MyApp->config> to L<Config::General> format in C<myapp.conf>:
319 $ CATALYST_DEBUG=0 perl -Ilib -e 'use MyApp; use Config::General;
320 Config::General->new->save_file("myapp.conf", MyApp->config);'
322 B<HOWEVER>, if you try out the command above, be sure to delete the
323 "myapp.conf" command. Otherwise, you will wind up with duplicate
326 B<NOTE:> Because we are using
327 L<SimpleDB|L<Catalyst::Authentication::Realm::SimpleDB> along with a
328 database layout that complies with its default assumptions: we don't
329 need to specify the names of the columns where our username and password
330 information is stored (hence, the "Simple" part of "SimpleDB"). That
331 being said, SimpleDB lets you specify that type of information if you
332 need to. Take a look at C<Catalyst::Authentication::Realm::SimpleDB>
336 =head2 Add Login and Logout Controllers
338 Use the Catalyst create script to create two stub controller files:
340 $ script/myapp_create.pl controller Login
341 $ script/myapp_create.pl controller Logout
343 You could easily use a single controller here. For example, you could
344 have a C<User> controller with both C<login> and C<logout> actions.
345 Remember, Catalyst is designed to be very flexible, and leaves such
346 matters up to you, the designer and programmer.
348 Then open C<lib/MyApp/Controller/Login.pm>, and update the definition of
349 C<sub index> to match:
357 sub index :Path :Args(0) {
360 # Get the username and password from form
361 my $username = $c->request->params->{username};
362 my $password = $c->request->params->{password};
364 # If the username and password values were found in form
365 if ($username && $password) {
366 # Attempt to log the user in
367 if ($c->authenticate({ username => $username,
368 password => $password } )) {
369 # If successful, then let them use the application
370 $c->response->redirect($c->uri_for(
371 $c->controller('Books')->action_for('list')));
374 # Set an error message
375 $c->stash(error_msg => "Bad username or password.");
378 # Set an error message
379 $c->stash(error_msg => "Empty username or password.")
380 unless ($c->user_exists);
383 # If either of above don't work out, send to the login page
384 $c->stash(template => 'login.tt2');
387 This controller fetches the C<username> and C<password> values from the
388 login form and attempts to authenticate the user. If successful, it
389 redirects the user to the book list page. If the login fails, the user
390 will stay at the login page and receive an error message. If the
391 C<username> and C<password> values are not present in the form, the user
392 will be taken to the empty login form.
394 Note that we could have used something like "C<sub default :Path>",
395 however, it is generally recommended (partly for historical reasons, and
396 partly for code clarity) only to use C<default> in
397 C<MyApp::Controller::Root>, and then mainly to generate the 404 not
398 found page for the application.
400 Instead, we are using "C<sub somename :Path :Args(0) {...}>" here to
401 specifically match the URL C</login>. C<Path> actions (aka, "literal
402 actions") create URI matches relative to the namespace of the controller
403 where they are defined. Although C<Path> supports arguments that allow
404 relative and absolute paths to be defined, here we use an empty C<Path>
405 definition to match on just the name of the controller itself. The
406 method name, C<index>, is arbitrary. We make the match even more
407 specific with the C<:Args(0)> action modifier -- this forces the match
408 on I<only> C</login>, not C</login/somethingelse>.
410 Next, update the corresponding method in
411 C<lib/MyApp/Controller/Logout.pm> to match:
419 sub index :Path :Args(0) {
422 # Clear the user's state
425 # Send the user to the starting point
426 $c->response->redirect($c->uri_for('/'));
430 =head2 Add a Login Form TT Template Page
432 Create a login form by opening C<root/src/login.tt2> and inserting:
434 [% META title = 'Login' %]
437 <form method="post" action="[% c.uri_for('/login') %]">
441 <td><input type="text" name="username" size="40" /></td>
445 <td><input type="password" name="password" size="40" /></td>
448 <td colspan="2"><input type="submit" name="submit" value="Submit" /></td>
454 =head2 Add Valid User Check
456 We need something that provides enforcement for the authentication
457 mechanism -- a I<global> mechanism that prevents users who have not
458 passed authentication from reaching any pages except the login page.
459 This is generally done via an C<auto> action/method in
460 C<lib/MyApp/Controller/Root.pm>.
462 Edit the existing C<lib/MyApp/Controller/Root.pm> class file and insert
463 the following method:
467 Check if there is a user and, if not, forward to login page
471 # Note that 'auto' runs after 'begin' but before your actions and that
472 # 'auto's "chain" (all from application path to most specific class are run)
473 # See the 'Actions' section of 'Catalyst::Manual::Intro' for more info.
477 # Allow unauthenticated users to reach the login page. This
478 # allows unauthenticated users to reach any action in the Login
479 # controller. To lock it down to a single action, we could use:
480 # if ($c->action eq $c->controller('Login')->action_for('index'))
481 # to only allow unauthenticated access to the 'index' action we
483 if ($c->controller eq $c->controller('Login')) {
487 # If a user doesn't exist, force login
488 if (!$c->user_exists) {
489 # Dump a log message to the development server debug output
490 $c->log->debug('***Root::auto User not found, forwarding to /login');
491 # Redirect the user to the login page
492 $c->response->redirect($c->uri_for('/login'));
493 # Return 0 to cancel 'post-auto' processing and prevent use of application
497 # User found, so return 1 to continue with processing after this 'auto'
502 L<Catalyst::Manual::Tutorial::03_MoreCatalystBasics/CREATE A CATALYST CONTROLLER>,
503 every C<auto> method from the application/root controller down to the
504 most specific controller will be called. By placing the authentication
505 enforcement code inside the C<auto> method of
506 C<lib/MyApp/Controller/Root.pm> (or C<lib/MyApp.pm>), it will be called
507 for I<every> request that is received by the entire application.
510 =head2 Displaying Content Only to Authenticated Users
512 Let's say you want to provide some information on the login page that
513 changes depending on whether the user has authenticated yet. To do
514 this, open C<root/src/login.tt2> in your editor and add the following
515 lines to the bottom of the file:
520 # This code illustrates how certain parts of the TT
521 # template will only be shown to users who have logged in
523 [% IF c.user_exists %]
524 Please Note: You are already logged in as '[% c.user.username %]'.
525 You can <a href="[% c.uri_for('/logout') %]">logout</a> here.
527 You need to log in to use this application.
530 Note that this whole block is a comment because the "#" appears
531 immediate after the "[%" (with no spaces in between). Although it
532 can be a handy way to temporarily "comment out" a whole block of
533 TT code, it's probably a little too subtle for use in "normal"
538 Although most of the code is comments, the middle few lines provide a
539 "you are already logged in" reminder if the user returns to the login
540 page after they have already authenticated. For users who have not yet
541 authenticated, a "You need to log in..." message is displayed (note the
542 use of an IF-THEN-ELSE construct in TT).
545 =head2 Try Out Authentication
547 The development server should have reloaded each time we edited one of
548 the Controllers in the previous section. Now try going to
549 L<http://localhost:3000/books/list> and you should be redirected to the
550 login page, hitting Shift+Reload or Ctrl+Reload if necessary (the "You
551 are already logged in" message should I<not> appear -- if it does, click
552 the C<logout> button and try again). Note the C<***Root::auto User not
553 found...> debug message in the development server output. Enter username
554 C<test01> and password C<mypass>, and you should be taken to the Book
557 B<IMPORTANT NOTE:> If you are having issues with authentication on
558 Internet Explorer (or potentially other browsers), be sure to check the
559 system clocks on both your server and client machines. Internet
560 Explorer is very picky about timestamps for cookies. You can use the
561 C<ntpq -p> command on the Tutorial Virtual Machine to check time sync
562 and/or use the following command to force a sync:
566 Or, depending on your firewall configuration, try it with "-u":
568 sudo ntpdate-debian -u
570 Note: NTP can be a little more finicky about firewalls because it uses
571 UDP vs. the more common TCP that you see with most Internet protocols.
572 Worse case, you might have to manually set the time on your development
573 box instead of using NTP.
575 Open C<root/src/books/list.tt2> and add the following lines to the
576 bottom (below the closing </table> tag):
580 <a href="[% c.uri_for('/login') %]">Login</a>
581 <a href="[% c.uri_for(c.controller.action_for('form_create')) %]">Create</a>
584 Reload your browser and you should now see a "Login" and "Create" links
585 at the bottom of the page (as mentioned earlier, you can update template
586 files without a development server reload). Click the first link to
587 return to the login page. This time you I<should> see the "You are
588 already logged in" message.
590 Finally, click the C<You can logout here> link on the C</login> page.
591 You should stay at the login page, but the message should change to "You
592 need to log in to use this application."
595 =head1 USING PASSWORD HASHES
597 In this section we increase the security of our system by converting
598 from cleartext passwords to SHA-1 password hashes that include a random
599 "salt" value to make them extremely difficult to crack, even with
600 dictionary and "rainbow table" attacks.
602 B<Note:> This section is optional. You can skip it and the rest of the
603 tutorial will function normally.
605 Be aware that even with the techniques shown in this section, the
606 browser still transmits the passwords in cleartext to your application.
607 We are just avoiding the I<storage> of cleartext passwords in the
608 database by using a salted SHA-1 hash. If you are concerned about
609 cleartext passwords between the browser and your application, consider
610 using SSL/TLS, made easy with modules such as
611 L<Catalyst::Plugin:RequireSSL> and L<Catalyst::ActionRole::RequireSSL>.
614 =head2 Re-Run the DBIC::Schema Model Helper to Include DBIx::Class::PassphraseColumn
616 Let's re-run the model helper to have it include
617 L<DBIx::Class::PassphraseColumn> in all of the Result Classes it
618 generates for us. Simply use the same command we saw in Chapters 3 and
619 4, but add C<,PassphraseColumn> to the C<components> argument:
621 $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
622 create=static components=TimeStamp,PassphraseColumn dbi:SQLite:myapp.db \
623 on_connect_do="PRAGMA foreign_keys = ON"
625 If you then open one of the Result Classes, you will see that it
626 includes PassphraseColumn in the C<load_components> line. Take a look
627 at C<lib/MyApp/Schema/Result/User.pm> since that's the main class where
628 we want to use hashed and salted passwords:
630 __PACKAGE__->load_components("InflateColumn::DateTime", "TimeStamp", "PassphraseColumn");
633 =head2 Modify the "password" Column to Use PassphraseColumn
635 Open the file C<lib/MyApp/Schema/Result/User.pm> and enter the following
636 text below the "# DO NOT MODIFY THIS OR ANYTHING ABOVE!" line but above
639 # Have the 'password' column use a SHA-1 hash and 20-byte salt
640 # with RFC 2307 encoding; Generate the 'check_password" method
641 __PACKAGE__->add_columns(
643 passphrase => 'rfc2307',
644 passphrase_class => 'SaltedDigest',
646 algorithm => 'SHA-1',
649 passphrase_check_method => 'check_password',
653 This redefines the automatically generated definition for the password
654 fields at the top of the Result Class file to now use PassphraseColumn
655 logic, storing passwords in RFC 2307 format (C<passphrase> is set to
656 C<rfc2307>). C<passphrase_class> can be set to the name of any
657 C<Authen::Passphrase::*> class, such as C<SaltedDigest> to use
658 L<Authen::Passphrase::SaltedDigest>, or C<BlowfishCrypt> to use
659 L<Authen::Passphrase::BlowfishCrypt>. C<passphrase_args> is then used
660 to customize the passphrase class you selected. Here we specified the
661 digest algorithm to use as C<SHA-1> and the size of the salt to use, but
662 we could have also specified any other option the selected passphrase
666 =head2 Load Hashed Passwords in the Database
668 Next, let's create a quick script to load some hashed and salted
669 passwords into the C<password> column of our C<users> table. Open the
670 file C<set_hashed_passwords.pl> in your editor and enter the following
680 my $schema = MyApp::Schema->connect('dbi:SQLite:myapp.db');
682 my @users = $schema->resultset('User')->all;
684 foreach my $user (@users) {
685 $user->password('mypass');
689 PassphraseColumn lets us simply call C<$user->check_password($password)>
690 to see if the user has supplied the correct password, or, as we show
691 above, call C<$user->update($new_password)> to update the hashed
692 password stored for this user.
694 Then run the following command:
696 $ DBIC_TRACE=1 perl -Ilib set_hashed_passwords.pl
698 We had to use the C<-Ilib> argument to tell Perl to look under the
699 C<lib> directory for our C<MyApp::Schema> model.
701 The DBIC_TRACE output should show that the update worked:
703 $ DBIC_TRACE=1 perl -Ilib set_hashed_passwords.pl
704 SELECT me.id, me.username, me.password, me.email_address,
705 me.first_name, me.last_name, me.active FROM users me:
706 UPDATE users SET password = ? WHERE ( id = ? ):
707 '{SSHA}esgz64CpHMo8pMfgIIszP13ft23z/zio04aCwNdm0wc6MDeloMUH4g==', '1'
708 UPDATE users SET password = ? WHERE ( id = ? ):
709 '{SSHA}FpGhpCJus+Ea9ne4ww8404HH+hJKW/fW+bAv1v6FuRUy2G7I2aoTRQ==', '2'
710 UPDATE users SET password = ? WHERE ( id = ? ):
711 '{SSHA}ZyGlpiHls8qFBSbHr3r5t/iqcZE602XLMbkSVRRNl6rF8imv1abQVg==', '3'
713 But we can further confirm our actions by dumping the users table:
715 $ sqlite3 myapp.db "select * from users"
716 1|test01|{SSHA}esgz64CpHMo8pMfgIIszP13ft23z/zio04aCwNdm0wc6MDeloMUH4g==|t01@na.com|Joe|Blow|1
717 2|test02|{SSHA}FpGhpCJus+Ea9ne4ww8404HH+hJKW/fW+bAv1v6FuRUy2G7I2aoTRQ==|t02@na.com|Jane|Doe|1
718 3|test03|{SSHA}ZyGlpiHls8qFBSbHr3r5t/iqcZE602XLMbkSVRRNl6rF8imv1abQVg==|t03@na.com|No|Go|0
720 As you can see, the passwords are much harder to steal from the database
721 (not only are the hashes stored, but every hash is different even though
722 the passwords are the same because of the added "salt" value). Also
723 note that this demonstrates how to use a DBIx::Class model outside of
724 your web application -- a very useful feature in many situations.
727 =head2 Enable Hashed and Salted Passwords
729 Edit C<lib/MyApp.pm> and update the config() section for
730 C<Plugin::Authentication> it to match the following text (the only
731 change is to the C<password_type> field):
733 # Configure SimpleDB Authentication
735 'Plugin::Authentication' => {
738 user_model => 'DB::User',
739 password_type => 'self_check',
744 The use of C<self_check> will cause
745 Catalyst::Plugin::Authentication::Store::DBIC to call the
746 C<check_password> method we enabled on our C<password> columns.
749 =head2 Try Out the Hashed Passwords
751 The development server should restart as soon as your save the
752 C<lib/MyApp.pm> file in the previous section. You should now be able to
753 go to L<http://localhost:3000/books/list> and login as before. When
754 done, click the "logout" link on the login page (or point your browser
755 at L<http://localhost:3000/logout>).
758 =head1 USING THE SESSION FOR FLASH
760 As discussed in the previous chapter of the tutorial, C<flash> allows
761 you to set variables in a way that is very similar to C<stash>, but it
762 will remain set across multiple requests. Once the value is read, it is
763 cleared (unless reset). Although C<flash> has nothing to do with
764 authentication, it does leverage the same session plugins. Now that
765 those plugins are enabled, let's go back and update the "delete and
766 redirect with query parameters" code seen at the end of the
767 L<Basic CRUD|Catalyst::Manual::Tutorial::04_BasicCRUD> chapter of the
768 tutorial to take advantage of C<flash>.
770 First, open C<lib/MyApp/Controller/Books.pm> and modify C<sub delete> to
771 match the following (everything after the model search line of code has
780 sub delete :Chained('object') :PathPart('delete') :Args(0) {
783 # Use the book object saved by 'object' and delete it along
784 # with related 'book_authors' entries
785 $c->stash->{object}->delete;
787 # Use 'flash' to save information across requests until it's read
788 $c->flash->{status_msg} = "Book deleted";
790 # Redirect the user back to the list page
791 $c->response->redirect($c->uri_for($self->action_for('list')));
794 Next, open C<root/src/wrapper.tt2> and update the TT code to pull from
795 flash vs. the C<status_msg> query parameter:
799 [%# Status and error messages %]
800 <span class="message">[% status_msg || c.flash.status_msg %]</span>
801 <span class="error">[% error_msg %]</span>
802 [%# This is where TT will stick all of your template's contents. -%]
804 </div><!-- end content -->
807 Although the sample above only shows the C<content> div, leave the rest
808 of the file intact -- the only change we made to replace "||
809 c.request.params.status_msg" with "c.flash.status_msg" in the
810 C<E<lt>span class="message"E<gt>> line.
815 Authenticate using the login screen and then point your browser to
816 L<http://localhost:3000/books/url_create/Test/1/4> to create an extra
817 several books. Click the "Return to list" link and delete one of the
818 "Test" books you just added. The C<flash> mechanism should retain our
819 "Book deleted" status message across the redirect.
821 B<NOTE:> While C<flash> will save information across multiple requests,
822 I<it does get cleared the first time it is read>. In general, this is
823 exactly what you want -- the C<flash> message will get displayed on the
824 next screen where it's appropriate, but it won't "keep showing up" after
825 that first time (unless you reset it). Please refer to
826 L<Catalyst::Plugin::Session> for additional information.
828 B<Note:> There is also a C<flash-to-stash> feature that will
829 automatically load the contents the contents of flash into stash,
830 allowing us to use the more typical C<c.flash.status_msg> in our TT
831 template in lieu of the more verbose C<status_msg || c.flash.status_msg>
832 we used above. Consult L<Catalyst::Plugin::Session> for additional
836 =head2 Switch To Catalyst::Plugin::StatusMessages
838 Although the query parameter technique we used in
839 L<Chapter 4|Catalyst::Manual::Tutorial::04_BasicCRUD> and the C<flash>
840 approach we used above will work in most cases, they both have their
841 drawbacks. The query parameters can leave the status message on the
842 screen longer than it should (for example, if the user hits refresh).
843 And C<flash> can display the wrong message on the wrong screen (flash
844 just shows the message on the next page for that user... if the user
845 has multiple windows or tabs open, then the wrong one can get the
848 L<Catalyst::Plugin::StatusMessage> is designed to address these
849 shortcomings. It stores the messages in the user's session (so they are
850 available across multiple requests), but ties each status message to a
851 random token. By passing this token across the redirect, we are no
852 longer relying on a potentially ambiguous "next request" like we do with
853 flash. And, because the message is deleted the first time it's
854 displayed, the user can hit refresh and still only see the message a
855 single time (even though the URL may continue to reference the token,
856 it's only displayed the first time). The use of C<StatusMessage>
857 or a similar mechanism is recommended for all Catalyst applications.
859 To enable C<StatusMessage>, first edit C<lib/MyApp.pm> and add
860 C<StatusMessage> to the list of plugins:
873 Session::State::Cookie
878 Then edit C<lib/MyApp/Controller/Books.pm> and modify the C<delete>
879 action to match the following:
881 sub delete :Chained('object') :PathPart('delete') :Args(0) {
884 # Saved the PK id for status_msg below
885 my $id = $c->stash->{object}->id;
887 # Use the book object saved by 'object' and delete it along
888 # with related 'book_authors' entries
889 $c->stash->{object}->delete;
891 # Redirect the user back to the list page
892 $c->response->redirect($c->uri_for($self->action_for('list'),
893 {mid => $c->set_status_msg("Deleted book $id")}));
896 This uses the C<set_status_msg> that the plugin added to C<$c> to save
897 the message under a random token. (If we wanted to save an error
898 message, we could have used C<set_error_msg>.) Because
899 C<set_status_msg> and C<set_error_msg> both return the random token, we
900 can assign that value to the "C<mid>" query parameter via C<uri_for> as
903 Next, we need to make sure that the list page will load display the
904 message. The easiest way to do this is to take advantage of the chained
905 dispatch we implemented in
906 L<Chapter 4|Catalyst::Manual::Tutorial::04_BasicCRUD>. Edit
907 C<lib/MyApp/Controller/Books.pm> again and update the C<base> action to
910 sub base :Chained('/') :PathPart('books') :CaptureArgs(0) {
913 # Store the ResultSet in stash so it's available for other methods
914 $c->stash(resultset => $c->model('DB::Book'));
916 # Print a message to the debug log
917 $c->log->debug('*** INSIDE BASE METHOD ***');
919 # Load status messages
920 $c->load_status_msgs;
923 That way, anything that chains off C<base> will automatically get any
924 status or error messages loaded into the stash. Let's convert the
925 C<list> action to take advantage of this. Modify the method signature
932 sub list :Chained('base') :PathParth('list') :Args(0) {
934 Finally, let's clean up the status/error message code in our wrapper
935 template. Edit C<root/src/wrapper.tt2> and change the "content" div
936 to match the following:
939 [%# Status and error messages %]
940 <span class="message">[% status_msg %]</span>
941 <span class="error">[% error_msg %]</span>
942 [%# This is where TT will stick all of your template's contents. -%]
944 </div><!-- end content -->
946 Now go to L<http://localhost:3000/books/list> in your browser. Delete
947 another of the "Test" books you added in the previous step. You should
948 get redirection from the C<delete> action back to the C<list> action,
949 but with a "mid=########" message ID query parameter. The screen should
950 say "Deleted book #" (where # is the PK id of the book you removed).
951 However, if you hit refresh in your browser, the status message is no
952 longer displayed (even though the URL does still contain the message ID
953 token, it is ignored -- thereby keeping the state of our status/error
954 messages in sync with the users actions).
957 You can jump to the next chapter of the tutorial here:
958 L<Authorization|Catalyst::Manual::Tutorial::06_Authorization>
963 Kennedy Clark, C<hkclark@gmail.com>
965 Feel free to contact the author for any errors or suggestions, but the
966 best way to report issues is via the CPAN RT Bug system at
967 <https://rt.cpan.org/Public/Dist/Display.html?Name=Catalyst-Manual>.
969 The most recent version of the Catalyst Tutorial can be found at
970 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
972 Copyright 2006-2010, Kennedy Clark, under the
973 Creative Commons Attribution Share-Alike License Version 3.0
974 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).