3 package Catalyst::Plugin::Session;
4 use base qw/Class::Accessor::Fast/;
10 use Catalyst::Exception ();
13 use Object::Signature ();
16 our $VERSION = "0.18";
18 my @session_data_accessors; # used in delete_session
20 __PACKAGE__->mk_accessors(
21 "_session_delete_reason",
22 @session_data_accessors = qw/
26 _extended_session_expires
31 _tried_loading_session_id
32 _tried_loading_session_data
33 _tried_loading_session_expires
34 _tried_loading_flash_data
44 $c->check_session_plugin_requirements;
50 sub check_session_plugin_requirements {
53 unless ( $c->isa("Catalyst::Plugin::Session::State")
54 && $c->isa("Catalyst::Plugin::Session::Store") )
57 ( "The Session plugin requires both Session::State "
58 . "and Session::Store plugins to be used as well." );
61 Catalyst::Exception->throw($err);
68 my $cfg = ( $c->config->{session} ||= {} );
76 $c->NEXT::setup_session();
82 if ( $c->config->{session}{flash_to_stash}
84 and my $flash_data = $c->flash )
86 @{ $c->stash }{ keys %$flash_data } = values %$flash_data;
89 $c->NEXT::prepare_action(@_);
95 my $ret = $c->NEXT::finalize(@_);
102 sub finalize_session {
105 $c->NEXT::finalize_session;
107 $c->_save_session_id;
110 $c->_save_session_expires;
112 $c->_clear_session_instance_data;
115 sub _save_session_id {
118 # we already called set when allocating
119 # no need to tell the state plugins anything new
122 sub _save_session_expires {
125 if ( defined($c->_session_expires) ) {
126 my $expires = $c->session_expires; # force extension
128 my $sid = $c->sessionid;
129 $c->store_session_data( "expires:$sid" => $expires );
136 if ( my $session_data = $c->_session ) {
138 no warnings 'uninitialized';
139 if ( Object::Signature::signature($session_data) ne
140 $c->_session_data_sig )
142 $session_data->{__updated} = time();
143 my $sid = $c->sessionid;
144 $c->store_session_data( "session:$sid" => $session_data );
152 if ( my $flash_data = $c->_flash ) {
154 my $hashes = $c->_flash_key_hashes || {};
155 my $keep = $c->_flash_keep_keys || {};
156 foreach my $key ( keys %$hashes ) {
157 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
158 delete $flash_data->{$key};
162 my $sid = $c->sessionid;
165 $c->store_session_data( "flash:$sid", $flash_data );
168 $c->delete_session_data("flash:$sid");
173 sub _load_session_expires {
175 return $c->_session_expires if $c->_tried_loading_session_expires;
176 $c->_tried_loading_session_expires(1);
178 if ( my $sid = $c->sessionid ) {
179 my $expires = $c->get_session_data("expires:$sid") || 0;
181 if ( $expires >= time() ) {
182 $c->_session_expires( $expires );
185 $c->delete_session( "session expired" );
195 return $c->_session if $c->_tried_loading_session_data;
196 $c->_tried_loading_session_data(1);
198 if ( my $sid = $c->sessionid ) {
199 if ( $c->_load_session_expires ) { # > 0
201 my $session_data = $c->get_session_data("session:$sid") || return;
202 $c->_session($session_data);
204 no warnings 'uninitialized'; # ne __address
205 if ( $c->config->{session}{verify_address}
206 && $session_data->{__address} ne $c->request->address )
209 "Deleting session $sid due to address mismatch ("
210 . $session_data->{__address} . " != "
211 . $c->request->address . ")"
213 $c->delete_session("address mismatch");
217 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
218 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
219 $c->_expire_session_keys;
221 return $session_data;
230 return $c->_flash if $c->_tried_loading_flash_data;
231 $c->_tried_loading_flash_data(1);
233 if ( my $sid = $c->sessionid ) {
234 if ( my $flash_data = $c->_flash
235 || $c->_flash( $c->get_session_data("flash:$sid") ) )
237 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
246 sub _expire_session_keys {
247 my ( $c, $data ) = @_;
251 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
252 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
253 delete $c->_session->{$key};
254 delete $expire_times->{$key};
258 sub _clear_session_instance_data {
260 $c->$_(undef) for @session_data_accessors;
261 $c->NEXT::_clear_session_instance_data; # allow other plugins to hook in on this
265 my ( $c, $msg ) = @_;
267 $c->log->debug("Deleting session" . ( defined($msg) ? "($msg)" : '(no reason given)') ) if $c->debug;
269 # delete the session data
270 if ( my $sid = $c->sessionid ) {
271 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
272 $c->delete_session_id($sid);
275 # reset the values in the context object
276 # see the BEGIN block
277 $c->_clear_session_instance_data;
279 $c->_session_delete_reason($msg);
282 sub session_delete_reason {
285 $c->session_is_valid; # check that it was loaded
287 $c->_session_delete_reason(@_);
290 sub session_expires {
293 if ( defined( my $expires = $c->_extended_session_expires ) ) {
295 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
296 return $c->extend_session_expires( $expires );
302 sub extend_session_expires {
303 my ( $c, $expires ) = @_;
304 $c->_extended_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
305 $c->extend_session_id( $c->sessionid, $updated );
309 sub calculate_initial_session_expires {
311 return ( time() + $c->config->{session}{expires} );
314 sub calculate_extended_session_expires {
315 my ( $c, $prev ) = @_;
316 $c->calculate_initial_session_expires;
319 sub reset_session_expires {
320 my ( $c, $sid ) = @_;
322 my $exp = $c->calculate_initial_session_expires;
323 $c->_session_expires( $exp );
324 $c->_extended_session_expires( $exp );
331 return $c->_sessionid || $c->_load_sessionid;
334 sub _load_sessionid {
336 return if $c->_tried_loading_session_id;
337 $c->_tried_loading_session_id(1);
339 if ( defined( my $sid = $c->get_session_id ) ) {
340 if ( $c->validate_session_id($sid) ) {
341 # temporarily set the inner key, so that validation will work
342 $c->_sessionid($sid);
345 my $err = "Tried to set invalid session ID '$sid'";
346 $c->log->error($err);
347 Catalyst::Exception->throw($err);
354 sub session_is_valid {
357 # force a check for expiry, but also __address, etc
358 if ( $c->_load_session ) {
365 sub validate_session_id {
366 my ( $c, $sid ) = @_;
368 $sid and $sid =~ /^[a-f\d]+$/i;
374 $c->_session || $c->_load_session || do {
375 $c->create_session_id_if_needed;
376 $c->initialize_session_data;
381 my ( $c, @keys ) = @_;
382 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
383 (@{$href}{@keys}) = ((undef) x @keys);
388 $c->_flash || $c->_load_flash || do {
389 $c->create_session_id_if_needed;
397 my $items = @_ > 1 ? {@_} : $_[0];
398 croak('flash takes a hash or hashref') unless ref $items;
399 @{ $c->_flash }{ keys %$items } = values %$items;
413 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
414 $c->_flash_key_hashes({});
415 $c->_flash_keep_keys({});
419 sub session_expire_key {
420 my ( $c, %keys ) = @_;
423 @{ $c->session->{__expire_keys} }{ keys %keys } =
424 map { $now + $_ } values %keys;
427 sub initialize_session_data {
438 $c->config->{session}{verify_address}
439 ? ( __address => $c->request->address )
446 sub generate_session_id {
449 my $digest = $c->_find_digest();
450 $digest->add( $c->session_hash_seed() );
451 return $digest->hexdigest;
454 sub create_session_id_if_needed {
456 $c->create_session_id unless $c->sessionid;
459 sub create_session_id {
462 my $sid = $c->generate_session_id;
464 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
466 $c->_sessionid($sid);
467 $c->reset_session_expires;
468 $c->set_session_id($sid);
475 sub session_hash_seed {
478 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
483 sub _find_digest () {
485 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
486 if ( eval { Digest->new($alg) } ) {
491 Catalyst::Exception->throw(
492 "Could not find a suitable Digest module. Please install "
493 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
497 return Digest->new($usable);
504 $c->NEXT::dump_these(),
507 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
513 sub get_session_id { shift->NEXT::get_session_id(@_) }
514 sub set_session_id { shift->NEXT::set_session_id(@_) }
515 sub delete_session_id { shift->NEXT::delete_session_id(@_) }
516 sub extend_session_id { shift->NEXT::extend_session_id(@_) }
526 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
527 storage and client side state required to maintain session data.
531 # To get sessions to "just work", all you need to do is use these plugins:
535 Session::Store::FastMmap
536 Session::State::Cookie
539 # you can replace Store::FastMmap with Store::File - both have sensible
540 # default configurations (see their docs for details)
542 # more complicated backends are available for other scenarios (DBI storage,
546 # after you've loaded the plugins you can save session data
547 # For example, if you are writing a shopping cart, it could be implemented
550 sub add_item : Local {
551 my ( $self, $c ) = @_;
553 my $item_id = $c->req->param("item");
555 # $c->session is a hash ref, a bit like $c->stash
556 # the difference is that it' preserved across requests
558 push @{ $c->session->{items} }, $item_id;
560 $c->forward("MyView");
563 sub display_items : Local {
564 my ( $self, $c ) = @_;
566 # values in $c->session are restored
567 $c->stash->{items_to_display} =
568 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
570 $c->forward("MyView");
575 The Session plugin is the base of two related parts of functionality required
576 for session management in web applications.
578 The first part, the State, is getting the browser to repeat back a session key,
579 so that the web application can identify the client and logically string
580 several requests together into a session.
582 The second part, the Store, deals with the actual storage of information about
583 the client. This data is stored so that the it may be revived for every request
584 made by the same client.
586 This plugin links the two pieces together.
588 =head1 RECOMENDED BACKENDS
592 =item Session::State::Cookie
594 The only really sane way to do state is using cookies.
596 =item Session::Store::File
598 A portable backend, based on Cache::File.
600 =item Session::Store::FastMmap
602 A fast and flexible backend, based on Cache::FastMmap.
612 An accessor for the session ID value.
616 Returns a hash reference that might contain unserialized values from previous
617 requests in the same session, and whose modified value will be saved for future
620 This method will automatically create a new session and session ID if none
623 =item session_expires
625 =item session_expires $reset
627 This method returns the time when the current session will expire, or 0 if
628 there is no current session. If there is a session and it already expired, it
629 will delete the session and return 0 as well.
631 If the C<$reset> parameter is true, and there is a session ID the expiry time
632 will be reset to the current time plus the time to live (see
633 L</CONFIGURATION>). This is used when creating a new session.
637 This is like Ruby on Rails' flash data structure. Think of it as a stash that
638 lasts for longer than one request, letting you redirect instead of forward.
640 The flash data will be cleaned up only on requests on which actually use
641 $c->flash (thus allowing multiple redirections), and the policy is to delete
642 all the keys which haven't changed since the flash data was loaded at the end
646 my ( $self, $c ) = @_;
648 $c->flash->{beans} = 10;
649 $c->response->redirect( $c->uri_for("foo") );
653 my ( $self, $c ) = @_;
655 my $value = $c->flash->{beans};
659 $c->response->redirect( $c->uri_for("bar") );
663 my ( $self, $c ) = @_;
665 if ( exists $c->flash->{beans} ) { # false
672 Zap all the keys in the flash regardless of their current state.
674 =item keep_flash @keys
676 If you wawnt to keep a flash key for the next request too, even if it hasn't
677 changed, call C<keep_flash> and pass in the keys as arguments.
679 =item delete_session REASON
681 This method is used to invalidate a session. It takes an optional parameter
682 which will be saved in C<session_delete_reason> if provided.
684 =item session_delete_reason
686 This accessor contains a string with the reason a session was deleted. Possible
701 =item session_expire_key $key, $ttl
703 Mark a key to expire at a certain time (only useful when shorter than the
704 expiry time for the whole session).
708 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
712 $c->session_expire_key( __user => 3600 );
714 Will make the session data survive, but the user will still be logged out after
717 Note that these values are not auto extended.
721 =head1 INTERNAL METHODS
727 This method is extended to also make calls to
728 C<check_session_plugin_requirements> and C<setup_session>.
730 =item check_session_plugin_requirements
732 This method ensures that a State and a Store plugin are also in use by the
737 This method populates C<< $c->config->{session} >> with the default values
738 listed in L</CONFIGURATION>.
742 This methoid is extended.
744 It's only effect is if the (off by default) C<flash_to_stash> configuration
745 parameter is on - then it will copy the contents of the flash to the stash at
750 This method is extended and will extend the expiry time, as well as persist the
751 session data if a session exists.
753 =item initialize_session_data
755 This method will initialize the internal structure of the session, and is
756 called by the C<session> method if appropriate.
758 =item create_session_id
760 Creates a new session id using C<generate_session_id> if there is no session ID
763 =item validate_session_id SID
765 Make sure a session ID is of the right format.
767 This currently ensures that the session ID string is any amount of case
768 insensitive hexadecimal characters.
770 =item generate_session_id
772 This method will return a string that can be used as a session ID. It is
773 supposed to be a reasonably random string with enough bits to prevent
774 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
775 MD5 or SHA-256, depending on the availibility of these modules.
777 =item session_hash_seed
779 This method is actually rather internal to generate_session_id, but should be
780 overridable in case you want to provide more random data.
782 Currently it returns a concatenated string which contains:
796 One value from C<rand>.
800 The stringified value of a newly allocated hash reference
804 The stringified value of the Catalyst context object
808 In the hopes that those combined values are entropic enough for most uses. If
809 this is not the case you can replace C<session_hash_seed> with e.g.
811 sub session_hash_seed {
812 open my $fh, "<", "/dev/random";
813 read $fh, my $bytes, 20;
818 Or even more directly, replace C<generate_session_id>:
820 sub generate_session_id {
821 open my $fh, "<", "/dev/random";
822 read $fh, my $bytes, 20;
824 return unpack("H*", $bytes);
827 Also have a look at L<Crypt::Random> and the various openssl bindings - these
828 modules provide APIs for cryptographically secure random data.
830 =item finalize_session
832 Clean up the session during C<finalize>.
834 This clears the various accessors after saving to the store.
838 See L<Catalyst/dump_these> - ammends the session data structure to the list of
839 dumped objects if session ID is defined.
843 =head1 USING SESSIONS DURING PREPARE
845 The earliest point in time at which you may use the session data is after
846 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
848 State plugins must set $c->session ID before C<prepare_action>, and during
849 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
855 # don't touch $c->session yet!
857 $c->NEXT::prepare_action( @_ );
859 $c->session; # this is OK
860 $c->sessionid; # this is also OK
865 $c->config->{session} = {
869 All configuation parameters are provided in a hash reference under the
870 C<session> key in the configuration hash.
876 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
881 When true, C<<$c->request->address>> will be checked at prepare time. If it is
882 not the same as the address that initiated the session, the session is deleted.
888 This option makes it easier to have actions behave the same whether they were
889 forwarded to or redirected to. On prepare time it copies the contents of
890 C<flash> (if any) to the stash.
896 The hash reference returned by C<< $c->session >> contains several keys which
897 are automatically set:
903 This key no longer exists. Use C<session_expires> instead.
907 The last time a session was saved to the store.
911 The time when the session was first created.
915 The value of C<< $c->request->address >> at the time the session was created.
916 This value is only populated if C<verify_address> is true in the configuration.
922 =head2 Round the Robin Proxies
924 C<verify_address> could make your site inaccessible to users who are behind
925 load balanced proxies. Some ISPs may give a different IP to each request by the
926 same client due to this type of proxying. If addresses are verified these
927 users' sessions cannot persist.
929 To let these users access your site you can either disable address verification
930 as a whole, or provide a checkbox in the login dialog that tells the server
931 that it's OK for the address of the client to change. When the server sees that
932 this box is checked it should delete the C<__address> sepcial key from the
933 session hash when the hash is first created.
935 =head2 Race Conditions
937 In this day and age where cleaning detergents and dutch football (not the
938 american kind) teams roam the plains in great numbers, requests may happen
939 simultaneously. This means that there is some risk of session data being
940 overwritten, like this:
946 request a starts, request b starts, with the same session id
950 session data is loaded in request a
954 session data is loaded in request b
958 session data is changed in request a
962 request a finishes, session data is updated and written to store
966 request b finishes, session data is updated and written to store, overwriting
971 If this is a concern in your application, a soon to be developed locking
972 solution is the only safe way to go. This will have a bigger overhead.
974 For applications where any given user is only making one request at a time this
975 plugin should be safe enough.
983 =item Christian Hansen
985 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
987 =item Sebastian Riedel
991 And countless other contributers from #catalyst. Thanks guys!
993 =head1 COPYRIGHT & LICENSE
995 Copyright (c) 2005 the aforementioned authors. All rights
996 reserved. This program is free software; you can redistribute
997 it and/or modify it under the same terms as Perl itself.