3 package Catalyst::Plugin::Session;
9 with 'MooseX::Emulate::Class::Accessor::Fast';
11 use Catalyst::Exception ();
14 use Object::Signature ();
17 our $VERSION = '0.21';
19 my @session_data_accessors; # used in delete_session
21 __PACKAGE__->mk_accessors(
22 "_session_delete_reason",
23 @session_data_accessors = qw/
27 _extended_session_expires
32 _tried_loading_session_id
33 _tried_loading_session_data
34 _tried_loading_session_expires
35 _tried_loading_flash_data
43 $c->maybe::next::method(@_);
45 $c->check_session_plugin_requirements;
51 sub check_session_plugin_requirements {
54 unless ( $c->isa("Catalyst::Plugin::Session::State")
55 && $c->isa("Catalyst::Plugin::Session::Store") )
58 ( "The Session plugin requires both Session::State "
59 . "and Session::Store plugins to be used as well." );
62 Catalyst::Exception->throw($err);
69 my $cfg = ( $c->config->{session} ||= {} );
77 $c->maybe::next::method();
83 if ( $c->config->{session}{flash_to_stash}
85 and my $flash_data = $c->flash )
87 @{ $c->stash }{ keys %$flash_data } = values %$flash_data;
90 $c->maybe::next::method(@_);
93 sub finalize_headers {
96 # fix cookie before we send headers
97 $c->_save_session_expires;
99 return $c->maybe::next::method(@_);
105 # We have to finalize our session *before* $c->engine->finalize_xxx is called,
106 # because we do not want to send the HTTP response before the session is stored/committed to
107 # the session database (or whatever Session::Store you use).
108 $c->finalize_session;
110 return $c->maybe::next::method(@_);
113 sub finalize_session {
116 $c->maybe::next::method(@_);
118 $c->_save_session_id;
122 $c->_clear_session_instance_data;
125 sub _save_session_id {
128 # we already called set when allocating
129 # no need to tell the state plugins anything new
132 sub _save_session_expires {
135 if ( defined($c->_session_expires) ) {
136 my $expires = $c->session_expires; # force extension
138 my $sid = $c->sessionid;
139 $c->store_session_data( "expires:$sid" => $expires );
146 if ( my $session_data = $c->_session ) {
148 no warnings 'uninitialized';
149 if ( Object::Signature::signature($session_data) ne
150 $c->_session_data_sig )
152 $session_data->{__updated} = time();
153 my $sid = $c->sessionid;
154 $c->store_session_data( "session:$sid" => $session_data );
162 if ( my $flash_data = $c->_flash ) {
164 my $hashes = $c->_flash_key_hashes || {};
165 my $keep = $c->_flash_keep_keys || {};
166 foreach my $key ( keys %$hashes ) {
167 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
168 delete $flash_data->{$key};
172 my $sid = $c->sessionid;
174 my $session_data = $c->_session;
176 $session_data->{__flash} = $flash_data;
179 delete $session_data->{__flash};
181 $c->_session($session_data);
186 sub _load_session_expires {
188 return $c->_session_expires if $c->_tried_loading_session_expires;
189 $c->_tried_loading_session_expires(1);
191 if ( my $sid = $c->sessionid ) {
192 my $expires = $c->get_session_data("expires:$sid") || 0;
194 if ( $expires >= time() ) {
195 $c->_session_expires( $expires );
198 $c->delete_session( "session expired" );
208 return $c->_session if $c->_tried_loading_session_data;
209 $c->_tried_loading_session_data(1);
211 if ( my $sid = $c->sessionid ) {
212 if ( $c->_load_session_expires ) { # > 0
214 my $session_data = $c->get_session_data("session:$sid") || return;
215 $c->_session($session_data);
217 no warnings 'uninitialized'; # ne __address
218 if ( $c->config->{session}{verify_address}
219 && $session_data->{__address} ne $c->request->address )
222 "Deleting session $sid due to address mismatch ("
223 . $session_data->{__address} . " != "
224 . $c->request->address . ")"
226 $c->delete_session("address mismatch");
230 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
231 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
232 $c->_expire_session_keys;
234 return $session_data;
243 return $c->_flash if $c->_tried_loading_flash_data;
244 $c->_tried_loading_flash_data(1);
246 if ( my $sid = $c->sessionid ) {
248 my $session_data = $c->session;
249 $c->_flash($session_data->{__flash});
251 if ( my $flash_data = $c->_flash )
253 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
262 sub _expire_session_keys {
263 my ( $c, $data ) = @_;
267 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
268 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
269 delete $c->_session->{$key};
270 delete $expire_times->{$key};
274 sub _clear_session_instance_data {
276 $c->$_(undef) for @session_data_accessors;
277 $c->maybe::next::method(@_); # allow other plugins to hook in on this
281 my ( $c, $msg ) = @_;
283 $c->log->debug("Deleting session" . ( defined($msg) ? "($msg)" : '(no reason given)') ) if $c->debug;
285 # delete the session data
286 if ( my $sid = $c->sessionid ) {
287 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
288 $c->delete_session_id($sid);
291 # reset the values in the context object
292 # see the BEGIN block
293 $c->_clear_session_instance_data;
295 $c->_session_delete_reason($msg);
298 sub session_delete_reason {
301 $c->session_is_valid; # check that it was loaded
303 $c->_session_delete_reason(@_);
306 sub session_expires {
309 if ( defined( my $expires = $c->_extended_session_expires ) ) {
311 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
312 return $c->extend_session_expires( $expires );
318 sub extend_session_expires {
319 my ( $c, $expires ) = @_;
320 $c->_extended_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
321 $c->extend_session_id( $c->sessionid, $updated );
325 sub calculate_initial_session_expires {
327 return ( time() + $c->config->{session}{expires} );
330 sub calculate_extended_session_expires {
331 my ( $c, $prev ) = @_;
332 $c->calculate_initial_session_expires;
335 sub reset_session_expires {
336 my ( $c, $sid ) = @_;
338 my $exp = $c->calculate_initial_session_expires;
339 $c->_session_expires( $exp );
340 $c->_extended_session_expires( $exp );
347 return $c->_sessionid || $c->_load_sessionid;
350 sub _load_sessionid {
352 return if $c->_tried_loading_session_id;
353 $c->_tried_loading_session_id(1);
355 if ( defined( my $sid = $c->get_session_id ) ) {
356 if ( $c->validate_session_id($sid) ) {
357 # temporarily set the inner key, so that validation will work
358 $c->_sessionid($sid);
361 my $err = "Tried to set invalid session ID '$sid'";
362 $c->log->error($err);
363 Catalyst::Exception->throw($err);
370 sub session_is_valid {
373 # force a check for expiry, but also __address, etc
374 if ( $c->_load_session ) {
381 sub validate_session_id {
382 my ( $c, $sid ) = @_;
384 $sid and $sid =~ /^[a-f\d]+$/i;
390 $c->_session || $c->_load_session || do {
391 $c->create_session_id_if_needed;
392 $c->initialize_session_data;
397 my ( $c, @keys ) = @_;
398 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
399 (@{$href}{@keys}) = ((undef) x @keys);
404 $c->_flash || $c->_load_flash || do {
405 $c->create_session_id_if_needed;
413 my $items = @_ > 1 ? {@_} : $_[0];
414 croak('flash takes a hash or hashref') unless ref $items;
415 @{ $c->_flash }{ keys %$items } = values %$items;
429 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
430 $c->_flash_key_hashes({});
431 $c->_flash_keep_keys({});
435 sub session_expire_key {
436 my ( $c, %keys ) = @_;
439 @{ $c->session->{__expire_keys} }{ keys %keys } =
440 map { $now + $_ } values %keys;
443 sub initialize_session_data {
454 $c->config->{session}{verify_address}
455 ? ( __address => $c->request->address )
462 sub generate_session_id {
465 my $digest = $c->_find_digest();
466 $digest->add( $c->session_hash_seed() );
467 return $digest->hexdigest;
470 sub create_session_id_if_needed {
472 $c->create_session_id unless $c->sessionid;
475 sub create_session_id {
478 my $sid = $c->generate_session_id;
480 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
482 $c->_sessionid($sid);
483 $c->reset_session_expires;
484 $c->set_session_id($sid);
491 sub session_hash_seed {
494 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
499 sub _find_digest () {
501 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
502 if ( eval { Digest->new($alg) } ) {
507 Catalyst::Exception->throw(
508 "Could not find a suitable Digest module. Please install "
509 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
513 return Digest->new($usable);
520 $c->maybe::next::method(),
523 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
529 sub get_session_id { shift->maybe::next::method(@_) }
530 sub set_session_id { shift->maybe::next::method(@_) }
531 sub delete_session_id { shift->maybe::next::method(@_) }
532 sub extend_session_id { shift->maybe::next::method(@_) }
542 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
546 # To get sessions to "just work", all you need to do is use these plugins:
550 Session::Store::FastMmap
551 Session::State::Cookie
554 # you can replace Store::FastMmap with Store::File - both have sensible
555 # default configurations (see their docs for details)
557 # more complicated backends are available for other scenarios (DBI storage,
561 # after you've loaded the plugins you can save session data
562 # For example, if you are writing a shopping cart, it could be implemented
565 sub add_item : Local {
566 my ( $self, $c ) = @_;
568 my $item_id = $c->req->param("item");
570 # $c->session is a hash ref, a bit like $c->stash
571 # the difference is that it' preserved across requests
573 push @{ $c->session->{items} }, $item_id;
575 $c->forward("MyView");
578 sub display_items : Local {
579 my ( $self, $c ) = @_;
581 # values in $c->session are restored
582 $c->stash->{items_to_display} =
583 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
585 $c->forward("MyView");
590 The Session plugin is the base of two related parts of functionality required
591 for session management in web applications.
593 The first part, the State, is getting the browser to repeat back a session key,
594 so that the web application can identify the client and logically string
595 several requests together into a session.
597 The second part, the Store, deals with the actual storage of information about
598 the client. This data is stored so that the it may be revived for every request
599 made by the same client.
601 This plugin links the two pieces together.
603 =head1 RECOMENDED BACKENDS
607 =item Session::State::Cookie
609 The only really sane way to do state is using cookies.
611 =item Session::Store::File
613 A portable backend, based on Cache::File.
615 =item Session::Store::FastMmap
617 A fast and flexible backend, based on Cache::FastMmap.
627 An accessor for the session ID value.
631 Returns a hash reference that might contain unserialized values from previous
632 requests in the same session, and whose modified value will be saved for future
635 This method will automatically create a new session and session ID if none
638 =item session_expires
640 =item session_expires $reset
642 This method returns the time when the current session will expire, or 0 if
643 there is no current session. If there is a session and it already expired, it
644 will delete the session and return 0 as well.
646 If the C<$reset> parameter is true, and there is a session ID the expiry time
647 will be reset to the current time plus the time to live (see
648 L</CONFIGURATION>). This is used when creating a new session.
652 This is like Ruby on Rails' flash data structure. Think of it as a stash that
653 lasts for longer than one request, letting you redirect instead of forward.
655 The flash data will be cleaned up only on requests on which actually use
656 $c->flash (thus allowing multiple redirections), and the policy is to delete
657 all the keys which haven't changed since the flash data was loaded at the end
661 my ( $self, $c ) = @_;
663 $c->flash->{beans} = 10;
664 $c->response->redirect( $c->uri_for("foo") );
668 my ( $self, $c ) = @_;
670 my $value = $c->flash->{beans};
674 $c->response->redirect( $c->uri_for("bar") );
678 my ( $self, $c ) = @_;
680 if ( exists $c->flash->{beans} ) { # false
687 Zap all the keys in the flash regardless of their current state.
689 =item keep_flash @keys
691 If you want to keep a flash key for the next request too, even if it hasn't
692 changed, call C<keep_flash> and pass in the keys as arguments.
694 =item delete_session REASON
696 This method is used to invalidate a session. It takes an optional parameter
697 which will be saved in C<session_delete_reason> if provided.
699 NOTE: This method will B<also> delete your flash data.
701 =item session_delete_reason
703 This accessor contains a string with the reason a session was deleted. Possible
718 =item session_expire_key $key, $ttl
720 Mark a key to expire at a certain time (only useful when shorter than the
721 expiry time for the whole session).
725 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
729 $c->session_expire_key( __user => 3600 );
731 Will make the session data survive, but the user will still be logged out after
734 Note that these values are not auto extended.
738 =head1 INTERNAL METHODS
744 This method is extended to also make calls to
745 C<check_session_plugin_requirements> and C<setup_session>.
747 =item check_session_plugin_requirements
749 This method ensures that a State and a Store plugin are also in use by the
754 This method populates C<< $c->config->{session} >> with the default values
755 listed in L</CONFIGURATION>.
759 This method is extended.
761 Its only effect is if the (off by default) C<flash_to_stash> configuration
762 parameter is on - then it will copy the contents of the flash to the stash at
765 =item finalize_headers
767 This method is extended and will extend the expiry time before sending
772 This method is extended and will call finalize_session before the other
773 finalize_body methods run. Here we persist the session data if a session exists.
775 =item initialize_session_data
777 This method will initialize the internal structure of the session, and is
778 called by the C<session> method if appropriate.
780 =item create_session_id
782 Creates a new session ID using C<generate_session_id> if there is no session ID
785 =item validate_session_id SID
787 Make sure a session ID is of the right format.
789 This currently ensures that the session ID string is any amount of case
790 insensitive hexadecimal characters.
792 =item generate_session_id
794 This method will return a string that can be used as a session ID. It is
795 supposed to be a reasonably random string with enough bits to prevent
796 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
797 MD5 or SHA-256, depending on the availability of these modules.
799 =item session_hash_seed
801 This method is actually rather internal to generate_session_id, but should be
802 overridable in case you want to provide more random data.
804 Currently it returns a concatenated string which contains:
810 =item * The current time
812 =item * One value from C<rand>.
814 =item * The stringified value of a newly allocated hash reference
816 =item * The stringified value of the Catalyst context object
820 in the hopes that those combined values are entropic enough for most uses. If
821 this is not the case you can replace C<session_hash_seed> with e.g.
823 sub session_hash_seed {
824 open my $fh, "<", "/dev/random";
825 read $fh, my $bytes, 20;
830 Or even more directly, replace C<generate_session_id>:
832 sub generate_session_id {
833 open my $fh, "<", "/dev/random";
834 read $fh, my $bytes, 20;
836 return unpack("H*", $bytes);
839 Also have a look at L<Crypt::Random> and the various openssl bindings - these
840 modules provide APIs for cryptographically secure random data.
842 =item finalize_session
844 Clean up the session during C<finalize>.
846 This clears the various accessors after saving to the store.
850 See L<Catalyst/dump_these> - ammends the session data structure to the list of
851 dumped objects if session ID is defined.
854 =item calculate_extended_session_expires
856 =item calculate_initial_session_expires
858 =item create_session_id_if_needed
860 =item delete_session_id
862 =item extend_session_expires
864 =item extend_session_id
868 =item reset_session_expires
870 =item session_is_valid
876 =head1 USING SESSIONS DURING PREPARE
878 The earliest point in time at which you may use the session data is after
879 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
881 State plugins must set $c->session ID before C<prepare_action>, and during
882 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
888 # don't touch $c->session yet!
890 $c->NEXT::prepare_action( @_ );
892 $c->session; # this is OK
893 $c->sessionid; # this is also OK
898 $c->config->{session} = {
902 All configuation parameters are provided in a hash reference under the
903 C<session> key in the configuration hash.
909 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
914 When true, C<<$c->request->address>> will be checked at prepare time. If it is
915 not the same as the address that initiated the session, the session is deleted.
921 This option makes it easier to have actions behave the same whether they were
922 forwarded to or redirected to. On prepare time it copies the contents of
923 C<flash> (if any) to the stash.
929 The hash reference returned by C<< $c->session >> contains several keys which
930 are automatically set:
936 This key no longer exists. Use C<session_expires> instead.
940 The last time a session was saved to the store.
944 The time when the session was first created.
948 The value of C<< $c->request->address >> at the time the session was created.
949 This value is only populated if C<verify_address> is true in the configuration.
955 =head2 Round the Robin Proxies
957 C<verify_address> could make your site inaccessible to users who are behind
958 load balanced proxies. Some ISPs may give a different IP to each request by the
959 same client due to this type of proxying. If addresses are verified these
960 users' sessions cannot persist.
962 To let these users access your site you can either disable address verification
963 as a whole, or provide a checkbox in the login dialog that tells the server
964 that it's OK for the address of the client to change. When the server sees that
965 this box is checked it should delete the C<__address> special key from the
966 session hash when the hash is first created.
968 =head2 Race Conditions
970 In this day and age where cleaning detergents and Dutch football (not the
971 American kind) teams roam the plains in great numbers, requests may happen
972 simultaneously. This means that there is some risk of session data being
973 overwritten, like this:
979 request a starts, request b starts, with the same session ID
983 session data is loaded in request a
987 session data is loaded in request b
991 session data is changed in request a
995 request a finishes, session data is updated and written to store
999 request b finishes, session data is updated and written to store, overwriting
1000 changes by request a
1004 If this is a concern in your application, a soon-to-be-developed locking
1005 solution is the only safe way to go. This will have a bigger overhead.
1007 For applications where any given user is only making one request at a time this
1008 plugin should be safe enough.
1016 Yuval Kogman, C<nothingmuch@woobling.org>
1020 Tomas Doran (t0m) C<bobtfish@bobtfish.net> (current maintainer)
1024 And countless other contributers from #catalyst. Thanks guys!
1026 =head1 COPYRIGHT & LICENSE
1028 Copyright (c) 2005 the aforementioned authors. All rights
1029 reserved. This program is free software; you can redistribute
1030 it and/or modify it under the same terms as Perl itself.