3 package Catalyst::Plugin::Authentication;
5 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
8 __PACKAGE__->mk_accessors(qw/_user/);
17 # this optimization breaks under Template::Toolkit
18 # use user_exists instead
21 # constant->import(have_want => eval { require Want });
24 our $VERSION = "0.09999_02";
26 sub set_authenticated {
27 my ( $c, $user, $realmname ) = @_;
30 $c->request->{user} = $user; # compatibility kludge
33 $realmname = 'default';
36 if ( $c->isa("Catalyst::Plugin::Session")
37 and $c->config->{authentication}{use_session}
38 and $user->supports("session") )
40 $c->save_user_in_session($user, $realmname);
42 $user->auth_realm($realmname);
43 $user->store(ref($c->auth_realms->{$realmname}{'store'}));
45 $c->NEXT::set_authenticated($user, $realmname);
48 sub _should_save_user_in_session {
49 my ( $c, $user ) = @_;
51 $c->_auth_sessions_supported
52 and $c->config->{authentication}{use_session}
53 and $user->supports("session");
56 sub _should_load_user_from_session {
57 my ( $c, $user ) = @_;
59 $c->_auth_sessions_supported
60 and $c->config->{authentication}{use_session}
61 and $c->session_is_valid;
64 sub _auth_sessions_supported {
66 $c->isa("Catalyst::Plugin::Session");
76 if ( defined($c->_user) ) {
79 return $c->auth_restore_user;
83 # change this to allow specification of a realm - to verify the user is part of that realm
84 # in addition to verifying that they exist.
87 return defined($c->_user) || defined($c->_user_in_session);
90 # works like user_exists - except only returns true if user
91 # exists AND is in the realm requested.
93 my ($c, $realmname) = @_;
95 if (defined($c->_user)) {
96 return ($c->_user->auth_realm eq $realmname);
97 } elsif (defined($c->_user_in_session)) {
98 return ($c->session->{__user_realm} eq $realmname);
104 sub save_user_in_session {
105 my ( $c, $user, $realmname ) = @_;
107 $c->session->{__user_realm} = $realmname;
109 # we want to ask the store for a user prepared for the session.
110 # but older modules split this functionality between the user and the
111 # store. We try the store first. If not, we use the old method.
112 my $realm = $c->get_auth_realm($realmname);
113 if ($realm->{'store'}->can('for_session')) {
114 $c->session->{__user} = $realm->{'store'}->for_session($c, $user);
116 $c->session->{__user} = $user->for_session;
126 $c->isa("Catalyst::Plugin::Session")
127 and $c->config->{authentication}{use_session}
128 and $c->session_is_valid
130 delete @{ $c->session }{qw/__user __user_realm/};
133 $c->NEXT::logout(@_);
137 my ( $c, $userinfo, $realmname ) = @_;
139 $realmname ||= 'default';
140 my $realm = $c->get_auth_realm($realmname);
141 if ( $realm->{'store'} ) {
142 return $realm->{'store'}->find_user($userinfo, $c);
144 $c->log->debug('find_user: unable to locate a store matching the requested realm');
149 sub _user_in_session {
152 return unless $c->_should_load_user_from_session;
154 return $c->session->{__user};
157 sub auth_restore_user {
158 my ( $c, $frozen_user, $realmname ) = @_;
160 $frozen_user ||= $c->_user_in_session;
161 return unless defined($frozen_user);
163 $realmname ||= $c->session->{__user_realm};
164 return unless $realmname; # FIXME die unless? This is an internal inconsistency
166 my $realm = $c->get_auth_realm($realmname);
167 $c->_user( my $user = $realm->{'store'}->from_session( $c, $frozen_user ) );
169 # this sets the realm the user originated in.
170 $user->auth_realm($realmname);
171 ## compatibility - some pre 0.10 store / credentials may need the store name,
172 ## this is not used by the current api in any form.
173 $user->store(ref($c->auth_realms->{$realmname}{'store'}));
179 # we can't actually do our setup in setup because the model has not yet been loaded.
180 # So we have to trigger off of setup_finished. :-(
184 $app->_authentication_initialize();
185 $app->NEXT::setup(@_);
188 ## the actual initialization routine. whee.
189 sub _authentication_initialize {
192 ## let's avoid recreating / configuring everything if we have already done it, eh?
193 if ($app->can('_auth_realms')) { return };
195 ## make classdata where it is used.
196 $app->mk_classdata( '_auth_realms' => {});
198 my $cfg = $app->config->{'authentication'} ||= {};
200 $cfg->{use_session} = 1;
202 if (exists($cfg->{'realms'})) {
203 foreach my $realm (keys %{$cfg->{'realms'}}) {
204 $app->setup_auth_realm($realm, $cfg->{'realms'}{$realm});
206 # if we have a 'default-realm' in the config hash and we don't already
207 # have a realm called 'default', we point default at the realm specified
208 if (exists($cfg->{'default_realm'}) && !$app->get_auth_realm('default')) {
209 $app->_set_default_auth_realm($cfg->{'default_realm'});
213 ## BACKWARDS COMPATIBILITY - if realm is not defined - then we are probably dealing
214 ## with an old-school config. The only caveat here is that we must add a classname
216 foreach my $storename (keys %{$cfg->{'stores'}}) {
218 store => $cfg->{'stores'}{$storename},
220 $app->setup_auth_realm($storename, $realmcfg);
227 sub setup_auth_realm {
228 my ($app, $realmname, $config) = @_;
230 $app->log->debug("Setting up auth realm $realmname") if $app->debug;
231 if (!exists($config->{'store'}{'class'})) {
232 Carp::croak "Couldn't setup the authentication realm named '$realmname', no class defined";
236 my $storeclass = $config->{'store'}{'class'};
238 ## follow catalyst class naming - a + prefix means a fully qualified class, otherwise it's
239 ## taken to mean C::P::A::Store::(specifiedclass)
240 if ($storeclass !~ /^\+(.*)$/ ) {
241 $storeclass = "Catalyst::Plugin::Authentication::Store::${storeclass}";
247 # a little niceness - since most systems seem to use the password credential class,
248 # if no credential class is specified we use password.
249 $config->{credential}{class} ||= "Catalyst::Plugin::Authentication::Credential::Password";
251 my $credentialclass = $config->{'credential'}{'class'};
253 ## follow catalyst class naming - a + prefix means a fully qualified class, otherwise it's
254 ## taken to mean C::P::A::Credential::(specifiedclass)
255 if ($credentialclass !~ /^\+(.*)$/ ) {
256 $credentialclass = "Catalyst::Plugin::Authentication::Credential::${credentialclass}";
258 $credentialclass = $1;
261 # if we made it here - we have what we need to load the classes;
262 Catalyst::Utils::ensure_class_loaded( $credentialclass );
263 Catalyst::Utils::ensure_class_loaded( $storeclass );
265 # BACKWARDS COMPATIBILITY - if the store class does not define find_user, we define it in terms
266 # of get_user and add it to the class. this is because the auth routines use find_user,
267 # and rely on it being present. (this avoids per-call checks)
268 if (!$storeclass->can('find_user')) {
270 *{"${storeclass}::find_user"} = sub {
271 my ($self, $info) = @_;
272 my @rest = @{$info->{rest}} if exists($info->{rest});
273 $self->get_user($info->{id}, @rest);
277 $app->auth_realms->{$realmname}{'store'} = $storeclass->new($config->{'store'}, $app);
278 $app->auth_realms->{$realmname}{'credential'} = $credentialclass->new($config->{'credential'}, $app);
283 return($self->_auth_realms);
287 my ($app, $realmname) = @_;
288 return $app->auth_realms->{$realmname};
292 # Very internal method. Vital Valuable Urgent, Do not touch on pain of death.
293 # Using this method just assigns the default realm to be the value associated
294 # with the realmname provided. It WILL overwrite any real realm called 'default'
295 # so can be very confusing if used improperly. It's used properly already.
296 # Translation: don't use it.
297 sub _set_default_auth_realm {
298 my ($app, $realmname) = @_;
300 if (exists($app->auth_realms->{$realmname})) {
301 $app->auth_realms->{'default'} = $app->auth_realms->{$realmname};
303 return $app->get_auth_realm('default');
307 my ($app, $userinfo, $realmname) = @_;
310 $realmname = 'default';
313 my $realm = $app->get_auth_realm($realmname);
315 ## note to self - make authenticate throw an exception if realm is invalid.
317 if ($realm && exists($realm->{'credential'})) {
318 my $user = $realm->{'credential'}->authenticate($app, $realm->{store}, $userinfo);
320 $app->set_authenticated($user, $realmname);
324 $app->log->debug("The realm requested, '$realmname' does not exist," .
325 " or there is no credential associated with it.")
330 ## BACKWARDS COMPATIBILITY -- Warning: Here be monsters!
332 # What follows are backwards compatibility routines - for use with Stores and Credentials
333 # that have not been updated to work with C::P::Authentication v0.10.
334 # These are here so as to not break people's existing installations, but will go away
335 # in a future version.
337 # The old style of configuration only supports a single store, as each store module
338 # sets itself as the default store upon being loaded. This is the only supported
339 # 'compatibility' mode.
343 my ( $c, $uid, @rest ) = @_;
345 return $c->find_user( {'id' => $uid, 'rest'=>\@rest }, 'default' );
349 ## this should only be called when using old-style authentication plugins. IF this gets
350 ## called in a new-style config - it will OVERWRITE the store of your default realm. Don't do it.
351 ## also - this is a partial setup - because no credential is instantiated... in other words it ONLY
352 ## works with old-style auth plugins and C::P::Authentication in compatibility mode. Trying to combine
353 ## this with a realm-type config will probably crash your app.
354 sub default_auth_store {
357 if ( my $new = shift ) {
358 $self->auth_realms->{'default'}{'store'} = $new;
359 my $storeclass = ref($new);
361 # BACKWARDS COMPATIBILITY - if the store class does not define find_user, we define it in terms
362 # of get_user and add it to the class. this is because the auth routines use find_user,
363 # and rely on it being present. (this avoids per-call checks)
364 if (!$storeclass->can('find_user')) {
366 *{"${storeclass}::find_user"} = sub {
367 my ($self, $info) = @_;
368 my @rest = @{$info->{rest}} if exists($info->{rest});
369 $self->get_user($info->{id}, @rest);
374 return $self->get_auth_realm('default')->{'store'};
377 ## BACKWARDS COMPATIBILITY
378 ## this only ever returns a hash containing 'default' - as that is the only
379 ## supported mode of calling this.
380 sub auth_store_names {
383 my %hash = ( $self->get_auth_realm('default')->{'store'} => 'default' );
387 my ( $self, $name ) = @_;
389 if ($name ne 'default') {
390 Carp::croak "get_auth_store called on non-default realm '$name'. Only default supported in compatibility mode";
392 $self->default_auth_store();
396 sub get_auth_store_name {
397 my ( $self, $store ) = @_;
401 # sub auth_stores is only used internally - here for completeness
405 my %hash = ( 'default' => $self->get_auth_realm('default')->{'store'});
416 Catalyst::Plugin::Authentication - Infrastructure plugin for the Catalyst
417 authentication framework.
426 $c->authenticate({ username => 'myusername',
427 password => 'mypassword' });
428 my $age = $c->user->get('age');
433 The authentication plugin provides generic user support for Catalyst apps. It
434 is the basis for both authentication (checking the user is who they claim to
435 be), and authorization (allowing the user to do what the system authorises
438 Using authentication is split into two parts. A Store is used to actually
439 store the user information, and can store any amount of data related to the
440 user. Credentials are used to verify users, using information from the store,
441 given data from the frontend. A Credential and a Store are paired to form a
442 'Realm'. A Catalyst application using the authentication framework must have
443 at least one realm, and may have several.
445 To implement authentication in a Catalyst application you need to add this
446 module, and specify at least one realm in the configuration.
448 Authentication data can also be stored in a session, if the application
449 is using the L<Catalyst::Plugin::Session> module.
451 B<NOTE> in version 0.10 of this module, the interface to this module changed.
452 Please see L</COMPATIBILITY ROUTINES> for more information.
456 =head2 The Authentication/Authorization Process
458 Web applications typically need to identify a user - to tell the user apart
459 from other users. This is usually done in order to display private information
460 that is only that user's business, or to limit access to the application so
461 that only certain entities can access certain parts.
463 This process is split up into several steps. First you ask the user to identify
464 themselves. At this point you can't be sure that the user is really who they
467 Then the user tells you who they are, and backs this claim with some piece of
468 information that only the real user could give you. For example, a password is
469 a secret that is known to both the user and you. When the user tells you this
470 password you can assume they're in on the secret and can be trusted (ignore
471 identity theft for now). Checking the password, or any other proof is called
472 B<credential verification>.
474 By this time you know exactly who the user is - the user's identity is
475 B<authenticated>. This is where this module's job stops, and your application
476 or other plugins step in.
478 The next logical step is B<authorization>, the process of deciding what a user
479 is (or isn't) allowed to do. For example, say your users are split into two
480 main groups - regular users and administrators. You want to verify that the
481 currently logged in user is indeed an administrator before performing the
482 actions in an administrative part of your application. These decisions may be
483 made within your application code using just the information available after
484 authentication, or it may be facilitated by a number of plugins.
486 =head2 The Components In This Framework
490 Configuration of the Catalyst::Plugin::Authentication framework is done in
491 terms of realms. In simplest terms, a realm is a pairing of a Credential
492 verifier and a User storage (Store) backend.
494 An application can have any number of Realms, each of which operates
495 independant of the others. Each realm has a name, which is used to identify it
496 as the target of an authentication request. This name can be anything, such as
497 'users' or 'members'. One realm must be defined as the default_realm, which is
498 used when no realm name is specified. More information about configuring
499 realms is available in the configuration section.
501 =head3 Credential Verifiers
503 When user input is transferred to the L<Catalyst> application (typically via
504 form inputs) the application may pass this information into the authentication
505 system through the $c->authenticate() method. From there, it is passed to the
506 appropriate Credential verifier.
508 These plugins check the data, and ensure that it really proves the user is who
511 =head3 Storage Backends
513 The authentication data also identifies a user, and the Storage backend modules
514 use this data to locate and return a standardized object-oriented
515 representation of a user.
517 When a user is retrieved from a store it is not necessarily authenticated.
518 Credential verifiers accept a set of authentication data and use this
519 information to retrieve the user from the store they are paired with.
521 =head3 The Core Plugin
523 This plugin on its own is the glue, providing realm configuration, session
524 integration, and other goodness for the other plugins.
528 More layers of plugins can be stacked on top of the authentication code. For
529 example, L<Catalyst::Plugin::Session::PerUser> provides an abstraction of
530 browser sessions that is more persistent per users.
531 L<Catalyst::Plugin::Authorization::Roles> provides an accepted way to separate
532 and group users into categories, and then check which categories the current
537 Let's say we were storing users in a simple perl hash. Users are
538 verified by supplying a password which is matched within the hash.
540 This means that our application will begin like this:
548 __PACKAGE__->config->{authentication} =
550 default_realm => 'members',
555 password_field => 'password',
556 password_type => 'clear'
562 password => "s00p3r",
564 roles => [qw/edit delete/],
567 password => "s3cr3t",
568 roles => [qw/comment/],
577 This tells the authentication plugin what realms are available, which
578 credential and store modules are used, and the configuration of each. With
579 this code loaded, we can now attempt to authenticate users.
581 To show an example of this, let's create an authentication controller:
583 package MyApp::Controller::Auth;
586 my ( $self, $c ) = @_;
588 if ( my $user = $c->req->param("user")
589 and my $password = $c->req->param("password") )
591 if ( $c->authenticate( { username => $user,
592 password => $password } ) ) {
593 $c->res->body( "hello " . $c->user->get("name") );
603 This code should be very readable. If all the necessary fields are supplied,
604 call the "authenticate" method from the controller. If it succeeds the
607 The credential verifier will attempt to retrieve the user whose details match
608 the authentication information provided to $c->authenticate(). Once it fetches
609 the user the password is checked and if it matches the user will be
610 B<authenticated> and C<< $c->user >> will contain the user object retrieved
613 In the above case, the default realm is checked, but we could just as easily
614 check an alternate realm. If this were an admin login, for example, we could
615 authenticate on the admin realm by simply changing the $c->authenticate()
618 if ( $c->authenticate( { username => $user,
619 password => $password }, 'admin' )l ) {
620 $c->res->body( "hello " . $c->user->get("name") );
624 Now suppose we want to restrict the ability to edit to a user with an
625 'editor' value of yes.
627 The restricted action might look like this:
630 my ( $self, $c ) = @_;
632 $c->detach("unauthorized")
633 unless $c->user_exists
634 and $c->user->get('editor') eq 'yes';
636 # do something restricted here
639 (Note that if you have multiple realms, you can use $c->user_in_realm('realmname')
640 in place of $c->user_exists(); This will essentially perform the same
641 verification as user_exists, with the added requirement that if there is a
642 user, it must have come from the realm specified.)
644 The above example is somewhat similar to role based access control.
645 L<Catalyst::Plugin::Authentication::Store::Minimal> treats the roles field as
646 an array of role names. Let's leverage this. Add the role authorization
655 my ( $self, $c ) = @_;
657 $c->detach("unauthorized") unless $c->check_roles("edit");
659 # do something restricted here
662 This is somewhat simpler and will work if you change your store, too, since the
663 role interface is consistent.
665 Let's say your app grew, and you now have 10000 users. It's no longer
666 efficient to maintain a hash of users, so you move this data to a database.
667 You can accomplish this simply by installing the DBIx::Class Store and
668 changing your config:
670 __PACKAGE__->config->{authentication} =
672 default_realm => 'members',
677 password_field => 'password',
678 password_type => 'clear'
681 class => 'DBIx::Class',
682 user_class => 'MyApp::Users',
683 role_column => 'roles'
689 The authentication system works behind the scenes to load your data from the
690 new source. The rest of your application is completely unchanged.
698 __PACKAGE__->config->{authentication} =
700 default_realm => 'members',
705 password_field => 'password',
706 password_type => 'clear'
709 class => 'DBIx::Class',
710 user_class => 'MyApp::Users',
711 role_column => 'roles'
717 password_field => 'password',
718 password_type => 'clear'
721 class => '+MyApp::Authentication::Store::NetAuth',
722 authserver => '192.168.10.17'
731 Whether or not to store the user's logged in state in the session, if the
732 application is also using L<Catalyst::Plugin::Session>. This
733 value is set to true per default.
737 This defines which realm should be used as when no realm is provided to methods
738 that require a realm such as authenticate or find_user.
742 This contains the series of realm configurations you want to use for your app.
743 The only rule here is that there must be at least one. A realm consists of a
744 name, which is used to reference the realm, a credential and a store.
746 Each realm config contains two hashes, one called 'credential' and one called
747 'store', each of which provide configuration details to the respective modules.
748 The contents of these hashes is specific to the module being used, with the
749 exception of the 'class' element, which tells the core Authentication module the
750 classname to instantiate.
752 The 'class' element follows the standard Catalyst mechanism of class
753 specification. If a class is prefixed with a +, it is assumed to be a complete
754 class name. Otherwise it is considered to be a portion of the class name. For
755 credentials, the classname 'B<Password>', for example, is expanded to
756 Catalyst::Plugin::Authentication::Credential::B<Password>. For stores, the
757 classname 'B<storename>' is expanded to:
758 Catalyst::Plugin::Authentication::Store::B<storename>.
768 =item authenticate( $userinfo, $realm )
770 Attempts to authenticate the user using the information in the $userinfo hash
771 reference using the realm $realm. $realm may be omitted, in which case the
772 default realm is checked.
776 Returns the currently logged in user or undef if there is none.
780 Returns true if a user is logged in right now. The difference between
781 user_exists and user is that user_exists will return true if a user is logged
782 in, even if it has not been yet retrieved from the storage backend. If you only
783 need to know if the user is logged in, depending on the storage mechanism this
784 can be much more efficient.
786 =item user_in_realm ( $realm )
788 Works like user_exists, except that it only returns true if a user is both
789 logged in right now and was retrieved from the realm provided.
793 Logs the user out, Deletes the currently logged in user from $c->user and the session.
795 =item find_user( $userinfo, $realm )
797 Fetch a particular users details, matching the provided user info, from the realm
802 =head1 INTERNAL METHODS
804 These methods are for Catalyst::Plugin::Authentication B<INTERNAL USE> only.
805 Please do not use them in your own code, whether application or credential /
806 store modules. If you do, you will very likely get the nasty shock of having
807 to fix / rewrite your code when things change. They are documented here only
812 =item set_authenticated ( $user, $realmname )
814 Marks a user as authenticated. This is called from within the authenticate
815 routine when a credential returns a user. $realmname defaults to 'default'
817 =item auth_restore_user ( $user, $realmname )
819 Used to restore a user from the session. In most cases this is called without
820 arguments to restore the user via the session. Can be called with arguments
821 when restoring a user from some other method. Currently not used in this way.
823 =item save_user_in_session ( $user, $realmname )
825 Used to save the user in a session. Saves $user in session, marked as
826 originating in $realmname. Both arguments are required.
830 Returns a hashref containing realmname -> realm instance pairs. Realm
831 instances contain an instantiated store and credential object as the 'store'
832 and 'credential' elements, respectively
834 =item get_auth_realm ( $realmname )
836 Retrieves the realm instance for the realmname provided.
844 This list might not be up to date. Below are modules known to work with the updated
845 API of 0.10 and are therefore compatible with realms.
847 =head2 User Storage Backends
849 L<Catalyst::Plugin::Authentication::Store::Minimal>,
850 L<Catalyst::Plugin::Authentication::Store::DBIx::Class>,
852 =head2 Credential verification
854 L<Catalyst::Plugin::Authentication::Credential::Password>,
858 L<Catalyst::Plugin::Authorization::ACL>,
859 L<Catalyst::Plugin::Authorization::Roles>
861 =head2 Internals Documentation
863 L<Catalyst::Plugin::Authentication::Internals>
867 L<Catalyst::Plugin::Session>,
868 L<Catalyst::Plugin::Session::PerUser>
870 =head1 DON'T SEE ALSO
872 This module along with its sub plugins deprecate a great number of other
873 modules. These include L<Catalyst::Plugin::Authentication::Simple>,
874 L<Catalyst::Plugin::Authentication::CDBI>.
876 At the time of writing these plugins have not yet been replaced or updated, but
877 should be eventually: L<Catalyst::Plugin::Authentication::OpenID>,
878 L<Catalyst::Plugin::Authentication::LDAP>,
879 L<Catalyst::Plugin::Authentication::CDBI::Basic>,
880 L<Catalyst::Plugin::Authentication::Basic::Remote>.
882 =head1 INCOMPATABILITIES
884 The realms based configuration and functionality of the 0.10 update
885 of L<Catalyst::Plugin::Authentication> required a change in the API used by
886 credentials and stores. It has a compatibility mode which allows use of
887 modules that have not yet been updated. This, however, completely mimics the
888 older api and disables the new realm-based features. In other words you can
889 not mix the older credential and store modules with realms, or realm-based
890 configs. The changes required to update modules are relatively minor and are
891 covered in L<Catalyst::Plugin::Authentication::Internals>. We hope that most
892 modules will move to the compatible list above very quickly.
894 =head1 COMPATIBILITY ROUTINES
896 In version 0.10 of L<Catalyst::Plugin::Authentication>, the API
897 changed. For app developers, this change is fairly minor, but for
898 Credential and Store authors, the changes are significant.
900 Please see the documentation in version 0.09 of
901 Catalyst::Plugin::Authentication for a better understanding of how the old API
904 The items below are still present in the plugin, though using them is
905 deprecated. They remain only as a transition tool, for those sites which can
906 not yet be upgraded to use the new system due to local customizations or use
907 of Credential / Store modules that have not yet been updated to work with the
910 These routines should not be used in any application using realms
911 functionality or any of the methods described above. These are for reference
918 This method is used to initiate authentication and user retrieval. Technically
919 this is part of the old Password credential module and it still resides in the
920 L<Password|Catalyst::Plugin::Authentication::Credential::Password> class. It is
921 included here for reference only.
923 =item default_auth_store
925 Return the store whose name is 'default'.
927 This is set to C<< $c->config->{authentication}{store} >> if that value exists,
928 or by using a Store plugin:
930 # load the Minimal authentication store.
931 use Catalyst qw/Authentication Authentication::Store::Minimal/;
933 Sets the default store to
934 L<Catalyst::Plugin::Authentication::Store::Minimal>.
936 =item get_auth_store $name
938 Return the store whose name is $name.
940 =item get_auth_store_name $store
942 Return the name of the store $store.
946 A hash keyed by name, with the stores registered in the app.
948 =item register_auth_stores %stores_by_name
950 Register stores into the application.
958 Yuval Kogman, C<nothingmuch@woobling.org>
960 Jay Kuri, C<jayk@cpan.org>
967 =head1 COPYRIGHT & LICENSE
969 Copyright (c) 2005 the aforementioned authors. All rights
970 reserved. This program is free software; you can redistribute
971 it and/or modify it under the same terms as Perl itself.