3 package Catalyst::Plugin::Session;
4 use base qw/Class::Accessor::Fast/;
10 use Catalyst::Exception ();
13 use Object::Signature ();
15 our $VERSION = "0.12";
17 my @session_data_accessors; # used in delete_session
19 __PACKAGE__->mk_accessors(
20 "_session_delete_reason",
21 @session_data_accessors = qw/
25 _extended_session_expires
30 _tried_loading_session_id
31 _tried_loading_session_data
32 _tried_loading_session_expires
33 _tried_loading_flash_data
43 $c->check_session_plugin_requirements;
49 sub check_session_plugin_requirements {
52 unless ( $c->isa("Catalyst::Plugin::Session::State")
53 && $c->isa("Catalyst::Plugin::Session::Store") )
56 ( "The Session plugin requires both Session::State "
57 . "and Session::Store plugins to be used as well." );
60 Catalyst::Exception->throw($err);
67 my $cfg = ( $c->config->{session} ||= {} );
75 $c->NEXT::setup_session();
81 if ( $c->config->{session}{flash_to_stash}
83 and my $flash_data = $c->flash )
85 @{ $c->stash }{ keys %$flash_data } = values %$flash_data;
88 $c->NEXT::prepare_action(@_);
96 $c->NEXT::finalize(@_);
99 sub finalize_session {
102 $c->NEXT::finalize_session;
104 $c->_save_session_id;
107 $c->_save_session_expires;
109 $c->_clear_session_instance_data;
112 sub _save_session_id {
115 # we already called set when allocating
116 # no need to tell the state plugins anything new
119 sub _save_session_expires {
122 if ( defined($c->_session_expires) ) {
123 my $expires = $c->session_expires; # force extension
125 my $sid = $c->sessionid;
126 $c->store_session_data( "expires:$sid" => $expires );
133 if ( my $session_data = $c->_session ) {
135 no warnings 'uninitialized';
136 if ( Object::Signature::signature($session_data) ne
137 $c->_session_data_sig )
139 $session_data->{__updated} = time();
140 my $sid = $c->sessionid;
141 $c->store_session_data( "session:$sid" => $session_data );
149 if ( my $flash_data = $c->_flash ) {
151 my $hashes = $c->_flash_key_hashes || {};
152 my $keep = $c->_flash_keep_keys || {};
153 foreach my $key ( keys %$hashes ) {
154 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
155 delete $flash_data->{$key};
159 my $sid = $c->sessionid;
162 $c->store_session_data( "flash:$sid", $flash_data );
165 $c->delete_session_data("flash:$sid");
170 sub _load_session_expires {
172 return $c->_session_expires if $c->_tried_loading_session_expires;
173 $c->_tried_loading_session_expires(1);
175 if ( my $sid = $c->sessionid ) {
176 my $expires = $c->get_session_data("expires:$sid") || 0;
178 if ( $expires >= time() ) {
179 $c->_session_expires( $expires );
182 $c->delete_session( "session expired" );
192 return $c->_session if $c->_tried_loading_session_data;
193 $c->_tried_loading_session_data(1);
195 if ( my $sid = $c->sessionid ) {
196 if ( $c->_load_session_expires ) { # > 0
198 my $session_data = $c->get_session_data("session:$sid") || return;
199 $c->_session($session_data);
201 no warnings 'uninitialized'; # ne __address
202 if ( $c->config->{session}{verify_address}
203 && $session_data->{__address} ne $c->request->address )
206 "Deleting session $sid due to address mismatch ("
207 . $session_data->{__address} . " != "
208 . $c->request->address . ")"
210 $c->delete_session("address mismatch");
214 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
215 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
216 $c->_expire_session_keys;
218 return $session_data;
227 return $c->_flash if $c->_tried_loading_flash_data;
228 $c->_tried_loading_flash_data(1);
230 if ( my $sid = $c->sessionid ) {
231 if ( my $flash_data = $c->_flash
232 || $c->_flash( $c->get_session_data("flash:$sid") ) )
234 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
243 sub _expire_session_keys {
244 my ( $c, $data ) = @_;
248 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
249 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
250 delete $c->_session->{$key};
251 delete $expire_times->{$key};
255 sub _clear_session_instance_data {
257 $c->$_(undef) for @session_data_accessors;
258 $c->NEXT::_clear_session_instance_data; # allow other plugins to hook in on this
262 my ( $c, $msg ) = @_;
264 $c->log->debug("Deleting session" . ( defined($msg) ? "($msg)" : '(no reason given)') ) if $c->debug;
266 # delete the session data
267 if ( my $sid = $c->sessionid ) {
268 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
269 $c->delete_session_id($sid);
272 # reset the values in the context object
273 # see the BEGIN block
274 $c->_clear_session_instance_data;
276 $c->_session_delete_reason($msg);
279 sub session_delete_reason {
282 $c->session_is_valid; # check that it was loaded
284 $c->_session_delete_reason(@_);
287 sub session_expires {
290 if ( defined( my $expires = $c->_extended_session_expires ) ) {
292 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
293 return $c->extend_session_expires( $expires );
299 sub extend_session_expires {
300 my ( $c, $expires ) = @_;
301 $c->_extended_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
302 $c->extend_session_id( $c->sessionid, $updated );
306 sub calculate_initial_session_expires {
308 return ( time() + $c->config->{session}{expires} );
311 sub calculate_extended_session_expires {
312 my ( $c, $prev ) = @_;
313 $c->calculate_initial_session_expires;
316 sub reset_session_expires {
317 my ( $c, $sid ) = @_;
319 my $exp = $c->calculate_initial_session_expires;
320 $c->_session_expires( $exp );
321 $c->_extended_session_expires( $exp );
328 return $c->_sessionid || $c->_load_sessionid;
331 sub _load_sessionid {
333 return if $c->_tried_loading_session_id;
334 $c->_tried_loading_session_id(1);
336 if ( defined( my $sid = $c->get_session_id ) ) {
337 if ( $c->validate_session_id($sid) ) {
338 # temporarily set the inner key, so that validation will work
339 $c->_sessionid($sid);
342 my $err = "Tried to set invalid session ID '$sid'";
343 $c->log->error($err);
344 Catalyst::Exception->throw($err);
351 sub session_is_valid {
354 # force a check for expiry, but also __address, etc
355 if ( $c->_load_session ) {
362 sub validate_session_id {
363 my ( $c, $sid ) = @_;
365 $sid and $sid =~ /^[a-f\d]+$/i;
371 $c->_session || $c->_load_session || do {
372 $c->create_session_id_if_needed;
373 $c->initialize_session_data;
378 my ( $c, @keys ) = @_;
379 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
380 (@{$href}{@keys}) = ((undef) x @keys);
385 $c->_flash || $c->_load_flash || do {
386 $c->create_session_id_if_needed;
393 $c->_flash_key_hashes({});
397 sub session_expire_key {
398 my ( $c, %keys ) = @_;
401 @{ $c->session->{__expire_keys} }{ keys %keys } =
402 map { $now + $_ } values %keys;
405 sub initialize_session_data {
416 $c->config->{session}{verify_address}
417 ? ( __address => $c->request->address )
424 sub generate_session_id {
427 my $digest = $c->_find_digest();
428 $digest->add( $c->session_hash_seed() );
429 return $digest->hexdigest;
432 sub create_session_id_if_needed {
434 $c->create_session_id unless $c->sessionid;
437 sub create_session_id {
440 my $sid = $c->generate_session_id;
442 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
444 $c->_sessionid($sid);
445 $c->reset_session_expires;
446 $c->set_session_id($sid);
453 sub session_hash_seed {
456 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
461 sub _find_digest () {
463 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
464 if ( eval { Digest->new($alg) } ) {
469 Catalyst::Exception->throw(
470 "Could not find a suitable Digest module. Please install "
471 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
475 return Digest->new($usable);
482 $c->NEXT::dump_these(),
485 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
491 sub get_session_id { shift->NEXT::get_session_id(@_) }
492 sub set_session_id { shift->NEXT::set_session_id(@_) }
493 sub delete_session_id { shift->NEXT::delete_session_id(@_) }
494 sub extend_session_id { shift->NEXT::extend_session_id(@_) }
504 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
505 storage and client side state required to maintain session data.
509 # To get sessions to "just work", all you need to do is use these plugins:
513 Session::Store::FastMmap
514 Session::State::Cookie
517 # you can replace Store::FastMmap with Store::File - both have sensible
518 # default configurations (see their docs for details)
520 # more complicated backends are available for other scenarios (DBI storage,
524 # after you've loaded the plugins you can save session data
525 # For example, if you are writing a shopping cart, it could be implemented
528 sub add_item : Local {
529 my ( $self, $c ) = @_;
531 my $item_id = $c->req->param("item");
533 # $c->session is a hash ref, a bit like $c->stash
534 # the difference is that it' preserved across requests
536 push @{ $c->session->{items} }, $item_id;
538 $c->forward("MyView");
541 sub display_items : Local {
542 my ( $self, $c ) = @_;
544 # values in $c->session are restored
545 $c->stash->{items_to_display} =
546 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
548 $c->forward("MyView");
553 The Session plugin is the base of two related parts of functionality required
554 for session management in web applications.
556 The first part, the State, is getting the browser to repeat back a session key,
557 so that the web application can identify the client and logically string
558 several requests together into a session.
560 The second part, the Store, deals with the actual storage of information about
561 the client. This data is stored so that the it may be revived for every request
562 made by the same client.
564 This plugin links the two pieces together.
566 =head1 RECCOMENDED BACKENDS
570 =item Session::State::Cookie
572 The only really sane way to do state is using cookies.
574 =item Session::Store::File
576 A portable backend, based on Cache::File.
578 =item Session::Store::FastMmap
580 A fast and flexible backend, based on Cache::FastMmap.
590 An accessor for the session ID value.
594 Returns a hash reference that might contain unserialized values from previous
595 requests in the same session, and whose modified value will be saved for future
598 This method will automatically create a new session and session ID if none
601 =item session_expires
603 =item session_expires $reset
605 This method returns the time when the current session will expire, or 0 if
606 there is no current session. If there is a session and it already expired, it
607 will delete the session and return 0 as well.
609 If the C<$reset> parameter is true, and there is a session ID the expiry time
610 will be reset to the current time plus the time to live (see
611 L</CONFIGURATION>). This is used when creating a new session.
615 This is like Ruby on Rails' flash data structure. Think of it as a stash that
616 lasts for longer than one request, letting you redirect instead of forward.
618 The flash data will be cleaned up only on requests on which actually use
619 $c->flash (thus allowing multiple redirections), and the policy is to delete
620 all the keys which haven't changed since the flash data was loaded at the end
624 my ( $self, $c ) = @_;
626 $c->flash->{beans} = 10;
627 $c->response->redirect( $c->uri_for("foo") );
631 my ( $self, $c ) = @_;
633 my $value = $c->flash->{beans};
637 $c->response->redirect( $c->uri_for("bar") );
641 my ( $self, $c ) = @_;
643 if ( exists $c->flash->{beans} ) { # false
650 Zap all the keys in the flash regardless of their current state.
652 =item keep_flash @keys
654 If you wawnt to keep a flash key for the next request too, even if it hasn't
655 changed, call C<keep_flash> and pass in the keys as arguments.
657 =item delete_session REASON
659 This method is used to invalidate a session. It takes an optional parameter
660 which will be saved in C<session_delete_reason> if provided.
662 =item session_delete_reason
664 This accessor contains a string with the reason a session was deleted. Possible
679 =item session_expire_key $key, $ttl
681 Mark a key to expire at a certain time (only useful when shorter than the
682 expiry time for the whole session).
686 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
690 $c->session_expire_key( __user => 3600 );
692 Will make the session data survive, but the user will still be logged out after
695 Note that these values are not auto extended.
699 =head1 INTERNAL METHODS
705 This method is extended to also make calls to
706 C<check_session_plugin_requirements> and C<setup_session>.
708 =item check_session_plugin_requirements
710 This method ensures that a State and a Store plugin are also in use by the
715 This method populates C<< $c->config->{session} >> with the default values
716 listed in L</CONFIGURATION>.
720 This methoid is extended.
722 It's only effect is if the (off by default) C<flash_to_stash> configuration
723 parameter is on - then it will copy the contents of the flash to the stash at
728 This method is extended and will extend the expiry time, as well as persist the
729 session data if a session exists.
731 =item initialize_session_data
733 This method will initialize the internal structure of the session, and is
734 called by the C<session> method if appropriate.
736 =item create_session_id
738 Creates a new session id using C<generate_session_id> if there is no session ID
741 =item validate_session_id SID
743 Make sure a session ID is of the right format.
745 This currently ensures that the session ID string is any amount of case
746 insensitive hexadecimal characters.
748 =item generate_session_id
750 This method will return a string that can be used as a session ID. It is
751 supposed to be a reasonably random string with enough bits to prevent
752 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
753 MD5 or SHA-256, depending on the availibility of these modules.
755 =item session_hash_seed
757 This method is actually rather internal to generate_session_id, but should be
758 overridable in case you want to provide more random data.
760 Currently it returns a concatenated string which contains:
774 One value from C<rand>.
778 The stringified value of a newly allocated hash reference
782 The stringified value of the Catalyst context object
786 In the hopes that those combined values are entropic enough for most uses. If
787 this is not the case you can replace C<session_hash_seed> with e.g.
789 sub session_hash_seed {
790 open my $fh, "<", "/dev/random";
791 read $fh, my $bytes, 20;
796 Or even more directly, replace C<generate_session_id>:
798 sub generate_session_id {
799 open my $fh, "<", "/dev/random";
800 read $fh, my $bytes, 20;
802 return unpack("H*", $bytes);
805 Also have a look at L<Crypt::Random> and the various openssl bindings - these
806 modules provide APIs for cryptographically secure random data.
808 =item finalize_session
810 Clean up the session during C<finalize>.
812 This clears the various accessors after saving to the store.
816 See L<Catalyst/dump_these> - ammends the session data structure to the list of
817 dumped objects if session ID is defined.
821 =head1 USING SESSIONS DURING PREPARE
823 The earliest point in time at which you may use the session data is after
824 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
826 State plugins must set $c->session ID before C<prepare_action>, and during
827 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
833 # don't touch $c->session yet!
835 $c->NEXT::prepare_action( @_ );
837 $c->session; # this is OK
838 $c->sessionid; # this is also OK
843 $c->config->{session} = {
847 All configuation parameters are provided in a hash reference under the
848 C<session> key in the configuration hash.
854 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
859 When true, C<<$c->request->address>> will be checked at prepare time. If it is
860 not the same as the address that initiated the session, the session is deleted.
864 This option makes it easier to have actions behave the same whether they were
865 forwarded to or redirected to. On prepare time it copies the contents of
866 C<flash> (if any) to the stash.
872 The hash reference returned by C<< $c->session >> contains several keys which
873 are automatically set:
879 This key no longer exists. Use C<session_expires> instead.
883 The last time a session was saved to the store.
887 The time when the session was first created.
891 The value of C<< $c->request->address >> at the time the session was created.
892 This value is only populated if C<verify_address> is true in the configuration.
898 =head2 Round the Robin Proxies
900 C<verify_address> could make your site inaccessible to users who are behind
901 load balanced proxies. Some ISPs may give a different IP to each request by the
902 same client due to this type of proxying. If addresses are verified these
903 users' sessions cannot persist.
905 To let these users access your site you can either disable address verification
906 as a whole, or provide a checkbox in the login dialog that tells the server
907 that it's OK for the address of the client to change. When the server sees that
908 this box is checked it should delete the C<__address> sepcial key from the
909 session hash when the hash is first created.
911 =head2 Race Conditions
913 In this day and age where cleaning detergents and dutch football (not the
914 american kind) teams roam the plains in great numbers, requests may happen
915 simultaneously. This means that there is some risk of session data being
916 overwritten, like this:
922 request a starts, request b starts, with the same session id
926 session data is loaded in request a
930 session data is loaded in request b
934 session data is changed in request a
938 request a finishes, session data is updated and written to store
942 request b finishes, session data is updated and written to store, overwriting
947 If this is a concern in your application, a soon to be developed locking
948 solution is the only safe way to go. This will have a bigger overhead.
950 For applications where any given user is only making one request at a time this
951 plugin should be safe enough.
959 =item Christian Hansen
961 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
963 =item Sebastian Riedel
967 And countless other contributers from #catalyst. Thanks guys!
969 =head1 COPYRIGHT & LICENSE
971 Copyright (c) 2005 the aforementioned authors. All rights
972 reserved. This program is free software; you can redistribute
973 it and/or modify it under the same terms as Perl itself.