3 package Catalyst::Plugin::Session;
4 use base qw/Class::Accessor::Fast/;
10 use Catalyst::Exception ();
13 use Object::Signature ();
15 our $VERSION = "0.13";
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;
394 my $items = @_ > 1 ? {@_} : $_[0];
395 croak('flash takes a hash or hashref') unless ref $items;
396 @{ $c->_flash }{ keys %$items } = values %$items;
410 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
411 $c->_flash_key_hashes({});
412 $c->_flash_keep_keys({});
416 sub session_expire_key {
417 my ( $c, %keys ) = @_;
420 @{ $c->session->{__expire_keys} }{ keys %keys } =
421 map { $now + $_ } values %keys;
424 sub initialize_session_data {
435 $c->config->{session}{verify_address}
436 ? ( __address => $c->request->address )
443 sub generate_session_id {
446 my $digest = $c->_find_digest();
447 $digest->add( $c->session_hash_seed() );
448 return $digest->hexdigest;
451 sub create_session_id_if_needed {
453 $c->create_session_id unless $c->sessionid;
456 sub create_session_id {
459 my $sid = $c->generate_session_id;
461 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
463 $c->_sessionid($sid);
464 $c->reset_session_expires;
465 $c->set_session_id($sid);
472 sub session_hash_seed {
475 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
480 sub _find_digest () {
482 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
483 if ( eval { Digest->new($alg) } ) {
488 Catalyst::Exception->throw(
489 "Could not find a suitable Digest module. Please install "
490 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
494 return Digest->new($usable);
501 $c->NEXT::dump_these(),
504 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
510 sub get_session_id { shift->NEXT::get_session_id(@_) }
511 sub set_session_id { shift->NEXT::set_session_id(@_) }
512 sub delete_session_id { shift->NEXT::delete_session_id(@_) }
513 sub extend_session_id { shift->NEXT::extend_session_id(@_) }
523 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
524 storage and client side state required to maintain session data.
528 # To get sessions to "just work", all you need to do is use these plugins:
532 Session::Store::FastMmap
533 Session::State::Cookie
536 # you can replace Store::FastMmap with Store::File - both have sensible
537 # default configurations (see their docs for details)
539 # more complicated backends are available for other scenarios (DBI storage,
543 # after you've loaded the plugins you can save session data
544 # For example, if you are writing a shopping cart, it could be implemented
547 sub add_item : Local {
548 my ( $self, $c ) = @_;
550 my $item_id = $c->req->param("item");
552 # $c->session is a hash ref, a bit like $c->stash
553 # the difference is that it' preserved across requests
555 push @{ $c->session->{items} }, $item_id;
557 $c->forward("MyView");
560 sub display_items : Local {
561 my ( $self, $c ) = @_;
563 # values in $c->session are restored
564 $c->stash->{items_to_display} =
565 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
567 $c->forward("MyView");
572 The Session plugin is the base of two related parts of functionality required
573 for session management in web applications.
575 The first part, the State, is getting the browser to repeat back a session key,
576 so that the web application can identify the client and logically string
577 several requests together into a session.
579 The second part, the Store, deals with the actual storage of information about
580 the client. This data is stored so that the it may be revived for every request
581 made by the same client.
583 This plugin links the two pieces together.
585 =head1 RECCOMENDED BACKENDS
589 =item Session::State::Cookie
591 The only really sane way to do state is using cookies.
593 =item Session::Store::File
595 A portable backend, based on Cache::File.
597 =item Session::Store::FastMmap
599 A fast and flexible backend, based on Cache::FastMmap.
609 An accessor for the session ID value.
613 Returns a hash reference that might contain unserialized values from previous
614 requests in the same session, and whose modified value will be saved for future
617 This method will automatically create a new session and session ID if none
620 =item session_expires
622 =item session_expires $reset
624 This method returns the time when the current session will expire, or 0 if
625 there is no current session. If there is a session and it already expired, it
626 will delete the session and return 0 as well.
628 If the C<$reset> parameter is true, and there is a session ID the expiry time
629 will be reset to the current time plus the time to live (see
630 L</CONFIGURATION>). This is used when creating a new session.
634 This is like Ruby on Rails' flash data structure. Think of it as a stash that
635 lasts for longer than one request, letting you redirect instead of forward.
637 The flash data will be cleaned up only on requests on which actually use
638 $c->flash (thus allowing multiple redirections), and the policy is to delete
639 all the keys which haven't changed since the flash data was loaded at the end
643 my ( $self, $c ) = @_;
645 $c->flash->{beans} = 10;
646 $c->response->redirect( $c->uri_for("foo") );
650 my ( $self, $c ) = @_;
652 my $value = $c->flash->{beans};
656 $c->response->redirect( $c->uri_for("bar") );
660 my ( $self, $c ) = @_;
662 if ( exists $c->flash->{beans} ) { # false
669 Zap all the keys in the flash regardless of their current state.
671 =item keep_flash @keys
673 If you wawnt to keep a flash key for the next request too, even if it hasn't
674 changed, call C<keep_flash> and pass in the keys as arguments.
676 =item delete_session REASON
678 This method is used to invalidate a session. It takes an optional parameter
679 which will be saved in C<session_delete_reason> if provided.
681 =item session_delete_reason
683 This accessor contains a string with the reason a session was deleted. Possible
698 =item session_expire_key $key, $ttl
700 Mark a key to expire at a certain time (only useful when shorter than the
701 expiry time for the whole session).
705 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
709 $c->session_expire_key( __user => 3600 );
711 Will make the session data survive, but the user will still be logged out after
714 Note that these values are not auto extended.
718 =head1 INTERNAL METHODS
724 This method is extended to also make calls to
725 C<check_session_plugin_requirements> and C<setup_session>.
727 =item check_session_plugin_requirements
729 This method ensures that a State and a Store plugin are also in use by the
734 This method populates C<< $c->config->{session} >> with the default values
735 listed in L</CONFIGURATION>.
739 This methoid is extended.
741 It's only effect is if the (off by default) C<flash_to_stash> configuration
742 parameter is on - then it will copy the contents of the flash to the stash at
747 This method is extended and will extend the expiry time, as well as persist the
748 session data if a session exists.
750 =item initialize_session_data
752 This method will initialize the internal structure of the session, and is
753 called by the C<session> method if appropriate.
755 =item create_session_id
757 Creates a new session id using C<generate_session_id> if there is no session ID
760 =item validate_session_id SID
762 Make sure a session ID is of the right format.
764 This currently ensures that the session ID string is any amount of case
765 insensitive hexadecimal characters.
767 =item generate_session_id
769 This method will return a string that can be used as a session ID. It is
770 supposed to be a reasonably random string with enough bits to prevent
771 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
772 MD5 or SHA-256, depending on the availibility of these modules.
774 =item session_hash_seed
776 This method is actually rather internal to generate_session_id, but should be
777 overridable in case you want to provide more random data.
779 Currently it returns a concatenated string which contains:
793 One value from C<rand>.
797 The stringified value of a newly allocated hash reference
801 The stringified value of the Catalyst context object
805 In the hopes that those combined values are entropic enough for most uses. If
806 this is not the case you can replace C<session_hash_seed> with e.g.
808 sub session_hash_seed {
809 open my $fh, "<", "/dev/random";
810 read $fh, my $bytes, 20;
815 Or even more directly, replace C<generate_session_id>:
817 sub generate_session_id {
818 open my $fh, "<", "/dev/random";
819 read $fh, my $bytes, 20;
821 return unpack("H*", $bytes);
824 Also have a look at L<Crypt::Random> and the various openssl bindings - these
825 modules provide APIs for cryptographically secure random data.
827 =item finalize_session
829 Clean up the session during C<finalize>.
831 This clears the various accessors after saving to the store.
835 See L<Catalyst/dump_these> - ammends the session data structure to the list of
836 dumped objects if session ID is defined.
840 =head1 USING SESSIONS DURING PREPARE
842 The earliest point in time at which you may use the session data is after
843 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
845 State plugins must set $c->session ID before C<prepare_action>, and during
846 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
852 # don't touch $c->session yet!
854 $c->NEXT::prepare_action( @_ );
856 $c->session; # this is OK
857 $c->sessionid; # this is also OK
862 $c->config->{session} = {
866 All configuation parameters are provided in a hash reference under the
867 C<session> key in the configuration hash.
873 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
878 When true, C<<$c->request->address>> will be checked at prepare time. If it is
879 not the same as the address that initiated the session, the session is deleted.
885 This option makes it easier to have actions behave the same whether they were
886 forwarded to or redirected to. On prepare time it copies the contents of
887 C<flash> (if any) to the stash.
893 The hash reference returned by C<< $c->session >> contains several keys which
894 are automatically set:
900 This key no longer exists. Use C<session_expires> instead.
904 The last time a session was saved to the store.
908 The time when the session was first created.
912 The value of C<< $c->request->address >> at the time the session was created.
913 This value is only populated if C<verify_address> is true in the configuration.
919 =head2 Round the Robin Proxies
921 C<verify_address> could make your site inaccessible to users who are behind
922 load balanced proxies. Some ISPs may give a different IP to each request by the
923 same client due to this type of proxying. If addresses are verified these
924 users' sessions cannot persist.
926 To let these users access your site you can either disable address verification
927 as a whole, or provide a checkbox in the login dialog that tells the server
928 that it's OK for the address of the client to change. When the server sees that
929 this box is checked it should delete the C<__address> sepcial key from the
930 session hash when the hash is first created.
932 =head2 Race Conditions
934 In this day and age where cleaning detergents and dutch football (not the
935 american kind) teams roam the plains in great numbers, requests may happen
936 simultaneously. This means that there is some risk of session data being
937 overwritten, like this:
943 request a starts, request b starts, with the same session id
947 session data is loaded in request a
951 session data is loaded in request b
955 session data is changed in request a
959 request a finishes, session data is updated and written to store
963 request b finishes, session data is updated and written to store, overwriting
968 If this is a concern in your application, a soon to be developed locking
969 solution is the only safe way to go. This will have a bigger overhead.
971 For applications where any given user is only making one request at a time this
972 plugin should be safe enough.
980 =item Christian Hansen
982 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
984 =item Sebastian Riedel
988 And countless other contributers from #catalyst. Thanks guys!
990 =head1 COPYRIGHT & LICENSE
992 Copyright (c) 2005 the aforementioned authors. All rights
993 reserved. This program is free software; you can redistribute
994 it and/or modify it under the same terms as Perl itself.