=head1 NAME Catalyst::Manual::Tutorial::Authentication - Catalyst Tutorial - Part 5: Authentication =head1 OVERVIEW This is B for the Catalyst tutorial. L =over 4 =item 1 L =item 2 L =item 3 L =item 4 L =item 5 B =item 6 L =item 7 L =item 8 L =item 9 L =item 10 L =back =head1 DESCRIPTION Now that we finally have a simple yet functional application, we can focus on providing authentication (with authorization coming next in Part 5). This part of the tutorial is divided into two main sections: 1) basic, cleartext authentication and 2) hash-based authentication. You can checkout the source code for this example from the catalyst subversion repository as per the instructions in L =head1 BASIC AUTHENTICATION This section explores how to add authentication logic to a Catalyst application. =head2 Add Users and Roles to the Database First, we add both user and role information to the database (we will add the role information here although it will not be used until the authorization section, Part 5). Create a new SQL script file by opening C in your editor and insert: -- -- Add users and roles tables, along with a many-to-many join table -- CREATE TABLE users ( id INTEGER PRIMARY KEY, username TEXT, password TEXT, email_address TEXT, first_name TEXT, last_name TEXT, active INTEGER ); CREATE TABLE roles ( id INTEGER PRIMARY KEY, role TEXT ); CREATE TABLE user_roles ( user_id INTEGER, role_id INTEGER, PRIMARY KEY (user_id, role_id) ); -- -- Load up some initial test data -- INSERT INTO users VALUES (1, 'test01', 'mypass', 't01@na.com', 'Joe', 'Blow', 1); INSERT INTO users VALUES (2, 'test02', 'mypass', 't02@na.com', 'Jane', 'Doe', 1); INSERT INTO users VALUES (3, 'test03', 'mypass', 't03@na.com', 'No', 'Go', 0); INSERT INTO roles VALUES (1, 'user'); INSERT INTO roles VALUES (2, 'admin'); INSERT INTO user_roles VALUES (1, 1); INSERT INTO user_roles VALUES (1, 2); INSERT INTO user_roles VALUES (2, 1); INSERT INTO user_roles VALUES (3, 1); Then load this into the C database with the following command: $ sqlite3 myapp.db < myapp02.sql =head2 Add User and Role Information to DBIC Schema Although we could manually edit the DBIC schema information to include the new tables added in the previous step, let's use the C option on the DBIC model helper to do most of the work for us: $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema create=static dbi:SQLite:myapp.db $ ls lib/MyApp/Schema Authors.pm BookAuthors.pm Books.pm Roles.pm UserRoles.pm Users.pm Notice how the helper has added three new table-specific result source files to the C directory. And, more importantly, even if there were changes to the existing result source files, those changes would have only been written above the C<# DO NOT MODIFY THIS OR ANYTHING ABOVE!> comment and your hand-editted enhancements would have been preserved. Speaking of "hand-editted enhancements," we should now add relationship information to the three new result source files. Edit each of these files and add the following information between the C<# DO NOT MODIFY THIS OR ANYTHING ABOVE!> comment and the closing C<1;>: C: # # Set relationships: # # has_many(): # args: # 1) Name of relationship, DBIC will create accessor with this name # 2) Name of the model class referenced by this relationship # 3) Column name in *foreign* table __PACKAGE__->has_many(map_user_role => 'MyApp::Schema::UserRoles', 'user_id'); # many_to_many(): # args: # 1) Name of relationship, DBIC will create accessor with this name # 2) Name of has_many() relationship this many_to_many() is shortcut for # 3) Name of belongs_to() relationship in model class of has_many() above # You must already have the has_many() defined to use a many_to_many(). __PACKAGE__->many_to_many(roles => 'map_user_role', 'role'); C: # # Set relationships: # # has_many(): # args: # 1) Name of relationship, DBIC will create accessor with this name # 2) Name of the model class referenced by this relationship # 3) Column name in *foreign* table __PACKAGE__->has_many(map_user_role => 'MyApp::Schema::UserRoles', 'role_id'); C: # # Set relationships: # # belongs_to(): # args: # 1) Name of relationship, DBIC will create accessor with this name # 2) Name of the model class referenced by this relationship # 3) Column name in *this* table __PACKAGE__->belongs_to(user => 'MyApp::Schema::Users', 'user_id'); # belongs_to(): # args: # 1) Name of relationship, DBIC will create accessor with this name # 2) Name of the model class referenced by this relationship # 3) Column name in *this* table __PACKAGE__->belongs_to(role => 'MyApp::Schema::Roles', 'role_id'); The code for these three sets of updates is obviously very similar to the edits we made to the C, C, and C classes created in Part 3. Note that we do not need to make any change to the C schema file. It simple tells DBIC to load all of the result source files it finds in below the C directory, so it will automatically pick up our new table information. =head2 Sanity-Check Reload of Development Server We aren't ready to try out the authentication just yet; we only want to do a quick check to be sure our model loads correctly. Press C to kill the previous server instance (if it's still running) and restart it: $ script/myapp_server.pl Look for the three new model objects in the startup debug output: ... .-------------------------------------------------------------------+----------. | Class | Type | +-------------------------------------------------------------------+----------+ | MyApp::Controller::Books | instance | | MyApp::Controller::Root | instance | | MyApp::Model::DB | instance | | MyApp::Model::DB::Author | class | | MyApp::Model::DB::Books | class | | MyApp::Model::DB::BookAuthors | class | | MyApp::Model::DB::Roles | class | | MyApp::Model::DB::Users | class | | MyApp::Model::DB::UserRoles | class | | MyApp::View::TT | instance | '-------------------------------------------------------------------+----------' ... Again, notice that your "result source" classes have been "re-loaded" by Catalyst under C. =head2 Include Authentication and Session Plugins Edit C and update it as follows (everything below C is new): use Catalyst qw/ -Debug ConfigLoader Static::Simple StackTrace Authentication Session Session::Store::FastMmap Session::State::Cookie /; The C plugin supports Authentication while the C plugins are required to maintain state across multiple HTTP requests. Note that the only required Authentication class is the main one. This is a change that occurred in version 0.09999_01 of the C plugin. You B to specify a particular Authentication::Store or Authentication::Credential plugin. Instead, indicate the Store and Credential you want to use in your application configuration (see below). Note that there are several options for L (L is generally a good choice if you are on Unix; try L if you are on Win32) -- consult L and its subclasses for additional information and options (for example to use a database- backed session store). =head2 Configure Authentication Although C<__PACKAGE__-Econfig(name =E 'value');> is still supported, newer Catalyst applications tend to place all configuration information in C and automatically load this information into Cconfig> using the L plugin. First, as noted in Part 3 of the tutorial, Catalyst has recently switched from a default config file format of YAML to C (an apache-like format). In case you are using a version of Catalyst earlier than v5.7014, delete the C file and simply follow the directions below to create a new C file. Here, we need to load several parameters that tell L where to locate information in your database. To do this, edit the C file and update it to match: name MyApp default_realm dbic # Note this first definition would be the same as setting # __PACKAGE__->config->{authentication}->{realms}->{dbic} # ->{credential} = 'Password' in lib/MyApp.pm # # Specify that we are going to do password-based auth class Password # This is the name of the field in the users table with the # password stored in it password_field password # We are using an unencrypted password now password_type clear # Use DBIC to retrieve username, password & role information class DBIx::Class # This is the model object created by Catalyst::Model::DBIC # from your schema (you created 'MyApp::Schema::User' but as # the Catalyst startup debug messages show, it was loaded as # 'MyApp::Model::DB::Users'). # NOTE: Omit 'MyApp::Model' here just as you would when using # '$c->model("DB::Users)' user_class DB::Users # This is the name of the field in your 'users' table that # contains the user's name id_field username Inline comments in the code above explain how each field is being used. Note that you can use many other config file formats with catalyst. See L for details. =head2 Add Login and Logout Controllers Use the Catalyst create script to create two stub controller files: $ script/myapp_create.pl controller Login $ script/myapp_create.pl controller Logout B You could easily use a single controller here. For example, you could have a C controller with both C and C actions. Remember, Catalyst is designed to be very flexible, and leaves such matters up to you, the designer and programmer. Then open C, locate the C method (or C if you are using an older version of Catalyst) that was automatically inserted by the helpers when we created the Login controller above, and delete this line: $c->response->body('Matched MyApp::Controller::Login in Login.'); Then update it to match: =head2 index Login logic =cut sub index :Path :Args(0) { my ($self, $c) = @_; # Get the username and password from form my $username = $c->request->params->{username} || ""; my $password = $c->request->params->{password} || ""; # If the username and password values were found in form if ($username && $password) { # Attempt to log the user in if ($c->authenticate({ username => $username, password => $password} )) { # If successful, then let them use the application $c->response->redirect($c->uri_for('/books/list')); return; } else { # Set an error message $c->stash->{error_msg} = "Bad username or password."; } } # If either of above don't work out, send to the login page $c->stash->{template} = 'login.tt2'; } This controller fetches the C and C values from the login form and attempts to authenticate the user. If successful, it redirects the user to the book list page. If the login fails, the user will stay at the login page but receive an error message. If the C and C values are not present in the form, the user will be taken to the empty login form. Note that we could have used something like C, however partly for historical reasons, and partly for code clarity it is generally recommended only to use C in C, and then mainly to generate the 404 not found page for the application. Instead, we are using C here to specifically match the URL C. C actions (aka, "literal actions") create URI matches relative to the namespace of the controller where they are defined. Although C supports arguments that allow relative and absolute paths to be defined, here we use an empty C definition to match on just the name of the controller itself. The method name, C, is arbitrary. We make the match even more specific with the C<:Args(0)> action modifier -- this forces the match on I C, not C. Next, update the corresponding method in C to match: =head2 index Logout logic =cut sub index :Path :Args(0) { my ($self, $c) = @_; # Clear the user's state $c->logout; # Send the user to the starting point $c->response->redirect($c->uri_for('/')); } As with the login controller, be sure to delete the C<$c->response->body('Matched MyApp::Controller::Logout in Logout.');> line of the C. =head2 Add a Login Form TT Template Page Create a login form by opening C and inserting: [% META title = 'Login' %]
Username:
Password:
=head2 Add Valid User Check We need something that provides enforcement for the authentication mechanism -- a I mechanism that prevents users who have not passed authentication from reaching any pages except the login page. This is generally done via an C action/method (prior to Catalyst v5.66, this sort of thing would go in C, but starting in v5.66, the preferred location is C). Edit the existing C class file and insert the following method: =head2 auto Check if there is a user and, if not, forward to login page =cut # Note that 'auto' runs after 'begin' but before your actions and that # 'auto' "chain" (all from application path to most specific class are run) # See the 'Actions' section of 'Catalyst::Manual::Intro' for more info. sub auto : Private { my ($self, $c) = @_; # Allow unauthenticated users to reach the login page. This # allows anauthenticated users to reach any action in the Login # controller. To lock it down to a single action, we could use: # if ($c->action eq $c->controller('Login')->action_for('index')) # to only allow unauthenticated access to the C action we # added above. if ($c->controller eq $c->controller('Login')) { return 1; } # If a user doesn't exist, force login if (!$c->user_exists) { # Dump a log message to the development server debug output $c->log->debug('***Root::auto User not found, forwarding to /login'); # Redirect the user to the login page $c->response->redirect($c->uri_for('/login')); # Return 0 to cancel 'post-auto' processing and prevent use of application return 0; } # User found, so return 1 to continue with processing after this 'auto' return 1; } B Catalyst provides a number of different types of actions, such as C, C, C and the new C. You should refer to L for a more detailed explanation, but the following bullet points provide a quick introduction: =over 4 =item * The majority of application have traditionally use C actions for items that respond to user requests and C actions for those that do not directly respond to user input. =item * Newer Catalyst applications tend to use C actions and the C attribute because of their power and flexibility. You can specify the path to match relative to the namespace of the current module as an argument to C. For example C in C would match on the URL C but C would match on C. =item * Automatic "chaining" of actions by the dispatcher is a powerful feature that allows multiple methods to handle a single URL. See L for more information on chained actions. =item * There are five types of build-in C actions: C, C, C, C, and C. =item * With C, C, C, C private actions, only the most specific action of each type will be called. For example, if you define a C action in your controller it will I a C action in your application/root controller -- I the action in your controller will be called. =item * Unlike the other actions where only a single method is called for each request, I auto action along the chain of namespaces will be called. Each C action will be called I. =back By placing the authentication enforcement code inside the C method of C (or C), it will be called for I request that is received by the entire application. =head2 Displaying Content Only to Authenticated Users Let's say you want to provide some information on the login page that changes depending on whether the user has authenticated yet. To do this, open C in your editor and add the following lines to the bottom of the file:

[% # This code illustrates how certain parts of the TT # template will only be shown to users who have logged in %] [% IF Catalyst.user_exists %] Please Note: You are already logged in as '[% Catalyst.user.username %]'. You can logout here. [% ELSE %] You need to log in to use this application. [% END %] [%# Note that this whole block is a comment because the "#" appears immediate after the "[%" (with no spaces in between). Although it can be a handy way to temporarily "comment out" a whole block of TT code, it's probably a little too subtle for use in "normal" comments. %]

Although most of the code is comments, the middle few lines provide a "you are already logged in" reminder if the user returns to the login page after they have already authenticated. For users who have not yet authenticated, a "You need to log in..." message is displayed (note the use of an IF-THEN-ELSE construct in TT). =head2 Try Out Authentication Press C to kill the previous server instance (if it's still running) and restart it: $ script/myapp_server.pl B If you are having issues with authentication on Internet Explorer, be sure to check the system clocks on both your server and client machines. Internet Explorer is very picky about timestamps for cookies. Note that you can quickly sync an Ubuntu system with the following command: sudo ntpdate ntp.ubuntu.com Now trying going to L and you should be redirected to the login page, hitting Shift+Reload if necessary (the "You are already logged in" message should I appear -- if it does, click the C button and try again). Note the C<***Root::auto User not found...> debug message in the development server output. Enter username C and password C, and you should be taken to the Book List page. Open C and add the following lines to the bottom (below the closing tag):

Login Create

Reload your browser and you should now see a "Login" and "Create" links at the bottom of the page (as mentioned earlier, you can update template files without reloading the development server). Click the first link to return to the login page. This time you I see the "You are already logged in" message. Finally, click the C link on the C page. You should stay at the login page, but the message should change to "You need to log in to use this application." =head1 USING PASSWORD HASHES In this section we increase the security of our system by converting from cleartext passwords to SHA-1 password hashes. B This section is optional. You can skip it and the rest of the tutorial will function normally. Note that even with the techniques shown in this section, the browser still transmits the passwords in cleartext to your application. We are just avoiding the I of cleartext passwords in the database by using a SHA-1 hash. If you are concerned about cleartext passwords between the browser and your application, consider using SSL/TLS, made easy with the Catalyst plugin Catalyst::Plugin:RequireSSL. =head2 Get a SHA-1 Hash for the Password Catalyst uses the C module to support a variety of hashing algorithms. Here we will use SHA-1 (SHA = Secure Hash Algorithm). First, we should compute the SHA-1 hash for the "mypass" password we are using. The following command-line Perl script provides a "quick and dirty" way to do this: $ perl -MDigest::SHA -e 'print Digest::SHA::sha1_hex("mypass"), "\n"' e727d1464ae12436e899a726da5b2f11d8381b26 $ B If you are following along in Ubuntu, you will need to install C with the following command to run the example code above: sudo apt-get install libdigest-sha-perl B You should probably modify this code for production use to not read the password from the command line. By having the script prompt for the cleartext password, it avoids having the password linger in forms such as your C<.bash_history> files (assuming you are using BASH as your shell). An example of such a script can be found in Appendix 3. =head2 Switch to SHA-1 Password Hashes in the Database Next, we need to change the C column of our C table to store this hash value vs. the existing cleartext password. Open C in your editor and enter: -- -- Convert passwords to SHA-1 hashes -- UPDATE users SET password = 'e727d1464ae12436e899a726da5b2f11d8381b26' WHERE id = 1; UPDATE users SET password = 'e727d1464ae12436e899a726da5b2f11d8381b26' WHERE id = 2; UPDATE users SET password = 'e727d1464ae12436e899a726da5b2f11d8381b26' WHERE id = 3; Then use the following command to update the SQLite database: $ sqlite3 myapp.db < myapp03.sql B We are using SHA-1 hashes here, but many other hashing algorithms are supported. See C for more information. =head2 Enable SHA-1 Hash Passwords in C Edit C and update it to match (the C and C are new, everything else is the same): name MyApp default_realm dbic # Note this first definition would be the same as setting # __PACKAGE__->config->{authentication}->{realms}->{dbic} # ->{credential} = 'Password' in lib/MyApp.pm # # Specify that we are going to do password-based auth class Password # This is the name of the field in the users table with the # password stored in it password_field password # Switch to more secure hashed passwords password_type hashed # Use the SHA-1 hashing algorithm password_hash_type SHA-1 # Use DBIC to retrieve username, password & role information class DBIx::Class # This is the model object created by Catalyst::Model::DBIC # from your schema (you created 'MyApp::Schema::User' but as # the Catalyst startup debug messages show, it was loaded as # 'MyApp::Model::DB::Users'). # NOTE: Omit 'MyApp::Model' here just as you would when using # '$c->model("DB::Users)' user_class DB::Users # This is the name of the field in your 'users' table that # contains the user's name id_field username =head2 Try Out the Hashed Passwords Press C to kill the previous server instance (if it's still running) and restart it: $ script/myapp_server.pl You should now be able to go to L and login as before. When done, click the "Logout" link on the login page (or point your browser at L). =head1 USING THE SESSION FOR FLASH As discussed in Part 3 of the tutorial, C allows you to set variables in a way that is very similar to C, but it will remain set across multiple requests. Once the value is read, it is cleared (unless reset). Although C has nothing to do with authentication, it does leverage the same session plugins. Now that those plugins are enabled, let's go back and improve the "delete and redirect with query parameters" code seen at the end of the L part of the tutorial. First, open C and modify C to match the following (everything after the model search line of code has changed): =head2 delete Delete a book =cut sub delete : Local { # $id = primary key of book to delete my ($self, $c, $id) = @_; # Search for the book and then delete it $c->model('DB::Books')->search({id => $id})->delete_all; # Use 'flash' to save information across requests until it's read $c->flash->{status_msg} = "Book deleted"; # Redirect the user back to the list page $c->response->redirect($c->uri_for('/books/list')); } Next, open C and update the TT code to pull from flash vs. the C query parameter:
[% status_msg || Catalyst.flash.status_msg %] [% error_msg %] [% content %]
=head2 Try Out Flash Restart the development server and point your browser to L to create an extra several books. Click the "Return to list" link and delete one of the "Test" books you just added. The C mechanism should retain our "Book deleted" status message across the redirect. B While C will save information across multiple requests, I. In general, this is exactly what you want -- the C message will get displayed on the next screen where it's appropriate, but it won't "keep showing up" after that first time (unless you reset it). Please refer to L for additional information. =head2 Switch To Flash-To-Stash Although the a use of flash above is certainly an improvement over the C we employed in Part 4 of the tutorial, the C statement is a little ugly. A nice alternative is to use the C feature that automatically copies the content of flash to stash. This makes your code controller and template code work regardless of where it was directly access, a forward, or a redirect. To enable C, you can either set the value in C by changing the default C<__PACKAGE__-Econfig> setting to something like: __PACKAGE__->config( name => 'MyApp', session => {flash_to_stash => 1} ); B add the following to C: flash_to_stash 1 The C<__PACKAGE__-Econfig> option is probably preferable here since it's not something you will want to change at runtime without it possibly breaking some of your code. Then edit C and change the C line to look like the following: [% status_msg %] Restart the development server and go to L in your browser. Delete another of the "Test" books you added in the previous step. Flash should still maintain the status message across the redirect even though you are no longer explicitly accessing C. =head1 AUTHOR Kennedy Clark, C Please report any errors, issues or suggestions to the author. The most recent version of the Catalyst Tutorial can be found at L. Copyright 2006, Kennedy Clark, under Creative Commons License (L).