3 package Catalyst::Plugin::Session;
4 use base qw/Class::Accessor::Fast/;
10 use Catalyst::Exception ();
13 use Object::Signature ();
16 our $VERSION = '0.20';
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(@_);
92 sub finalize_headers {
95 # fix cookie before we send headers
96 $c->_save_session_expires;
98 return $c->NEXT::finalize_headers(@_);
103 my $ret = $c->NEXT::finalize(@_);
105 # then finish the rest
106 $c->finalize_session;
110 sub finalize_session {
113 $c->NEXT::finalize_session;
115 $c->_save_session_id;
119 $c->_clear_session_instance_data;
122 sub _save_session_id {
125 # we already called set when allocating
126 # no need to tell the state plugins anything new
129 sub _save_session_expires {
132 if ( defined($c->_session_expires) ) {
133 my $expires = $c->session_expires; # force extension
135 my $sid = $c->sessionid;
136 $c->store_session_data( "expires:$sid" => $expires );
143 if ( my $session_data = $c->_session ) {
145 no warnings 'uninitialized';
146 if ( Object::Signature::signature($session_data) ne
147 $c->_session_data_sig )
149 $session_data->{__updated} = time();
150 my $sid = $c->sessionid;
151 $c->store_session_data( "session:$sid" => $session_data );
159 if ( my $flash_data = $c->_flash ) {
161 my $hashes = $c->_flash_key_hashes || {};
162 my $keep = $c->_flash_keep_keys || {};
163 foreach my $key ( keys %$hashes ) {
164 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
165 delete $flash_data->{$key};
169 my $sid = $c->sessionid;
171 my $session_data = $c->_session;
173 $session_data->{__flash} = $flash_data;
176 delete $session_data->{__flash};
178 $c->_session($session_data);
183 sub _load_session_expires {
185 return $c->_session_expires if $c->_tried_loading_session_expires;
186 $c->_tried_loading_session_expires(1);
188 if ( my $sid = $c->sessionid ) {
189 my $expires = $c->get_session_data("expires:$sid") || 0;
191 if ( $expires >= time() ) {
192 $c->_session_expires( $expires );
195 $c->delete_session( "session expired" );
205 return $c->_session if $c->_tried_loading_session_data;
206 $c->_tried_loading_session_data(1);
208 if ( my $sid = $c->sessionid ) {
209 if ( $c->_load_session_expires ) { # > 0
211 my $session_data = $c->get_session_data("session:$sid") || return;
212 $c->_session($session_data);
214 no warnings 'uninitialized'; # ne __address
215 if ( $c->config->{session}{verify_address}
216 && $session_data->{__address} ne $c->request->address )
219 "Deleting session $sid due to address mismatch ("
220 . $session_data->{__address} . " != "
221 . $c->request->address . ")"
223 $c->delete_session("address mismatch");
227 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
228 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
229 $c->_expire_session_keys;
231 return $session_data;
240 return $c->_flash if $c->_tried_loading_flash_data;
241 $c->_tried_loading_flash_data(1);
243 if ( my $sid = $c->sessionid ) {
245 my $session_data = $c->session;
246 $c->_flash($session_data->{__flash});
248 if ( my $flash_data = $c->_flash )
250 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
259 sub _expire_session_keys {
260 my ( $c, $data ) = @_;
264 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
265 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
266 delete $c->_session->{$key};
267 delete $expire_times->{$key};
271 sub _clear_session_instance_data {
273 $c->$_(undef) for @session_data_accessors;
274 $c->NEXT::_clear_session_instance_data; # allow other plugins to hook in on this
278 my ( $c, $msg ) = @_;
280 $c->log->debug("Deleting session" . ( defined($msg) ? "($msg)" : '(no reason given)') ) if $c->debug;
282 # delete the session data
283 if ( my $sid = $c->sessionid ) {
284 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
285 $c->delete_session_id($sid);
288 # reset the values in the context object
289 # see the BEGIN block
290 $c->_clear_session_instance_data;
292 $c->_session_delete_reason($msg);
295 sub session_delete_reason {
298 $c->session_is_valid; # check that it was loaded
300 $c->_session_delete_reason(@_);
303 sub session_expires {
306 if ( defined( my $expires = $c->_extended_session_expires ) ) {
308 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
309 return $c->extend_session_expires( $expires );
315 sub extend_session_expires {
316 my ( $c, $expires ) = @_;
317 $c->_extended_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
318 $c->extend_session_id( $c->sessionid, $updated );
322 sub calculate_initial_session_expires {
324 return ( time() + $c->config->{session}{expires} );
327 sub calculate_extended_session_expires {
328 my ( $c, $prev ) = @_;
329 $c->calculate_initial_session_expires;
332 sub reset_session_expires {
333 my ( $c, $sid ) = @_;
335 my $exp = $c->calculate_initial_session_expires;
336 $c->_session_expires( $exp );
337 $c->_extended_session_expires( $exp );
344 return $c->_sessionid || $c->_load_sessionid;
347 sub _load_sessionid {
349 return if $c->_tried_loading_session_id;
350 $c->_tried_loading_session_id(1);
352 if ( defined( my $sid = $c->get_session_id ) ) {
353 if ( $c->validate_session_id($sid) ) {
354 # temporarily set the inner key, so that validation will work
355 $c->_sessionid($sid);
358 my $err = "Tried to set invalid session ID '$sid'";
359 $c->log->error($err);
360 Catalyst::Exception->throw($err);
367 sub session_is_valid {
370 # force a check for expiry, but also __address, etc
371 if ( $c->_load_session ) {
378 sub validate_session_id {
379 my ( $c, $sid ) = @_;
381 $sid and $sid =~ /^[a-f\d]+$/i;
387 $c->_session || $c->_load_session || do {
388 $c->create_session_id_if_needed;
389 $c->initialize_session_data;
394 my ( $c, @keys ) = @_;
395 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
396 (@{$href}{@keys}) = ((undef) x @keys);
401 $c->_flash || $c->_load_flash || do {
402 $c->create_session_id_if_needed;
410 my $items = @_ > 1 ? {@_} : $_[0];
411 croak('flash takes a hash or hashref') unless ref $items;
412 @{ $c->_flash }{ keys %$items } = values %$items;
426 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
427 $c->_flash_key_hashes({});
428 $c->_flash_keep_keys({});
432 sub session_expire_key {
433 my ( $c, %keys ) = @_;
436 @{ $c->session->{__expire_keys} }{ keys %keys } =
437 map { $now + $_ } values %keys;
440 sub initialize_session_data {
451 $c->config->{session}{verify_address}
452 ? ( __address => $c->request->address )
459 sub generate_session_id {
462 my $digest = $c->_find_digest();
463 $digest->add( $c->session_hash_seed() );
464 return $digest->hexdigest;
467 sub create_session_id_if_needed {
469 $c->create_session_id unless $c->sessionid;
472 sub create_session_id {
475 my $sid = $c->generate_session_id;
477 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
479 $c->_sessionid($sid);
480 $c->reset_session_expires;
481 $c->set_session_id($sid);
488 sub session_hash_seed {
491 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
496 sub _find_digest () {
498 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
499 if ( eval { Digest->new($alg) } ) {
504 Catalyst::Exception->throw(
505 "Could not find a suitable Digest module. Please install "
506 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
510 return Digest->new($usable);
517 $c->NEXT::dump_these(),
520 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
526 sub get_session_id { shift->NEXT::get_session_id(@_) }
527 sub set_session_id { shift->NEXT::set_session_id(@_) }
528 sub delete_session_id { shift->NEXT::delete_session_id(@_) }
529 sub extend_session_id { shift->NEXT::extend_session_id(@_) }
539 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
543 # To get sessions to "just work", all you need to do is use these plugins:
547 Session::Store::FastMmap
548 Session::State::Cookie
551 # you can replace Store::FastMmap with Store::File - both have sensible
552 # default configurations (see their docs for details)
554 # more complicated backends are available for other scenarios (DBI storage,
558 # after you've loaded the plugins you can save session data
559 # For example, if you are writing a shopping cart, it could be implemented
562 sub add_item : Local {
563 my ( $self, $c ) = @_;
565 my $item_id = $c->req->param("item");
567 # $c->session is a hash ref, a bit like $c->stash
568 # the difference is that it' preserved across requests
570 push @{ $c->session->{items} }, $item_id;
572 $c->forward("MyView");
575 sub display_items : Local {
576 my ( $self, $c ) = @_;
578 # values in $c->session are restored
579 $c->stash->{items_to_display} =
580 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
582 $c->forward("MyView");
587 The Session plugin is the base of two related parts of functionality required
588 for session management in web applications.
590 The first part, the State, is getting the browser to repeat back a session key,
591 so that the web application can identify the client and logically string
592 several requests together into a session.
594 The second part, the Store, deals with the actual storage of information about
595 the client. This data is stored so that the it may be revived for every request
596 made by the same client.
598 This plugin links the two pieces together.
600 =head1 RECOMENDED BACKENDS
604 =item Session::State::Cookie
606 The only really sane way to do state is using cookies.
608 =item Session::Store::File
610 A portable backend, based on Cache::File.
612 =item Session::Store::FastMmap
614 A fast and flexible backend, based on Cache::FastMmap.
624 An accessor for the session ID value.
628 Returns a hash reference that might contain unserialized values from previous
629 requests in the same session, and whose modified value will be saved for future
632 This method will automatically create a new session and session ID if none
635 =item session_expires
637 =item session_expires $reset
639 This method returns the time when the current session will expire, or 0 if
640 there is no current session. If there is a session and it already expired, it
641 will delete the session and return 0 as well.
643 If the C<$reset> parameter is true, and there is a session ID the expiry time
644 will be reset to the current time plus the time to live (see
645 L</CONFIGURATION>). This is used when creating a new session.
649 This is like Ruby on Rails' flash data structure. Think of it as a stash that
650 lasts for longer than one request, letting you redirect instead of forward.
652 The flash data will be cleaned up only on requests on which actually use
653 $c->flash (thus allowing multiple redirections), and the policy is to delete
654 all the keys which haven't changed since the flash data was loaded at the end
658 my ( $self, $c ) = @_;
660 $c->flash->{beans} = 10;
661 $c->response->redirect( $c->uri_for("foo") );
665 my ( $self, $c ) = @_;
667 my $value = $c->flash->{beans};
671 $c->response->redirect( $c->uri_for("bar") );
675 my ( $self, $c ) = @_;
677 if ( exists $c->flash->{beans} ) { # false
684 Zap all the keys in the flash regardless of their current state.
686 =item keep_flash @keys
688 If you want to keep a flash key for the next request too, even if it hasn't
689 changed, call C<keep_flash> and pass in the keys as arguments.
691 =item delete_session REASON
693 This method is used to invalidate a session. It takes an optional parameter
694 which will be saved in C<session_delete_reason> if provided.
696 NOTE: This method will B<also> delete your flash data.
698 =item session_delete_reason
700 This accessor contains a string with the reason a session was deleted. Possible
715 =item session_expire_key $key, $ttl
717 Mark a key to expire at a certain time (only useful when shorter than the
718 expiry time for the whole session).
722 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
726 $c->session_expire_key( __user => 3600 );
728 Will make the session data survive, but the user will still be logged out after
731 Note that these values are not auto extended.
735 =head1 INTERNAL METHODS
741 This method is extended to also make calls to
742 C<check_session_plugin_requirements> and C<setup_session>.
744 =item check_session_plugin_requirements
746 This method ensures that a State and a Store plugin are also in use by the
751 This method populates C<< $c->config->{session} >> with the default values
752 listed in L</CONFIGURATION>.
756 This method is extended.
758 Its only effect is if the (off by default) C<flash_to_stash> configuration
759 parameter is on - then it will copy the contents of the flash to the stash at
762 =item finalize_headers
764 This method is extended and will extend the expiry time before sending
769 This method is extended and will call finalize_session after the other
770 finalizes run. Here we persist the session data if a session exists.
772 =item initialize_session_data
774 This method will initialize the internal structure of the session, and is
775 called by the C<session> method if appropriate.
777 =item create_session_id
779 Creates a new session ID using C<generate_session_id> if there is no session ID
782 =item validate_session_id SID
784 Make sure a session ID is of the right format.
786 This currently ensures that the session ID string is any amount of case
787 insensitive hexadecimal characters.
789 =item generate_session_id
791 This method will return a string that can be used as a session ID. It is
792 supposed to be a reasonably random string with enough bits to prevent
793 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
794 MD5 or SHA-256, depending on the availability of these modules.
796 =item session_hash_seed
798 This method is actually rather internal to generate_session_id, but should be
799 overridable in case you want to provide more random data.
801 Currently it returns a concatenated string which contains:
807 =item * The current time
809 =item * One value from C<rand>.
811 =item * The stringified value of a newly allocated hash reference
813 =item * The stringified value of the Catalyst context object
817 in the hopes that those combined values are entropic enough for most uses. If
818 this is not the case you can replace C<session_hash_seed> with e.g.
820 sub session_hash_seed {
821 open my $fh, "<", "/dev/random";
822 read $fh, my $bytes, 20;
827 Or even more directly, replace C<generate_session_id>:
829 sub generate_session_id {
830 open my $fh, "<", "/dev/random";
831 read $fh, my $bytes, 20;
833 return unpack("H*", $bytes);
836 Also have a look at L<Crypt::Random> and the various openssl bindings - these
837 modules provide APIs for cryptographically secure random data.
839 =item finalize_session
841 Clean up the session during C<finalize>.
843 This clears the various accessors after saving to the store.
847 See L<Catalyst/dump_these> - ammends the session data structure to the list of
848 dumped objects if session ID is defined.
851 =item calculate_extended_session_expires
853 =item calculate_initial_session_expires
855 =item create_session_id_if_needed
857 =item delete_session_id
859 =item extend_session_expires
861 =item extend_session_id
865 =item reset_session_expires
867 =item session_is_valid
873 =head1 USING SESSIONS DURING PREPARE
875 The earliest point in time at which you may use the session data is after
876 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
878 State plugins must set $c->session ID before C<prepare_action>, and during
879 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
885 # don't touch $c->session yet!
887 $c->NEXT::prepare_action( @_ );
889 $c->session; # this is OK
890 $c->sessionid; # this is also OK
895 $c->config->{session} = {
899 All configuation parameters are provided in a hash reference under the
900 C<session> key in the configuration hash.
906 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
911 When true, C<<$c->request->address>> will be checked at prepare time. If it is
912 not the same as the address that initiated the session, the session is deleted.
918 This option makes it easier to have actions behave the same whether they were
919 forwarded to or redirected to. On prepare time it copies the contents of
920 C<flash> (if any) to the stash.
926 The hash reference returned by C<< $c->session >> contains several keys which
927 are automatically set:
933 This key no longer exists. Use C<session_expires> instead.
937 The last time a session was saved to the store.
941 The time when the session was first created.
945 The value of C<< $c->request->address >> at the time the session was created.
946 This value is only populated if C<verify_address> is true in the configuration.
952 =head2 Round the Robin Proxies
954 C<verify_address> could make your site inaccessible to users who are behind
955 load balanced proxies. Some ISPs may give a different IP to each request by the
956 same client due to this type of proxying. If addresses are verified these
957 users' sessions cannot persist.
959 To let these users access your site you can either disable address verification
960 as a whole, or provide a checkbox in the login dialog that tells the server
961 that it's OK for the address of the client to change. When the server sees that
962 this box is checked it should delete the C<__address> special key from the
963 session hash when the hash is first created.
965 =head2 Race Conditions
967 In this day and age where cleaning detergents and Dutch football (not the
968 American kind) teams roam the plains in great numbers, requests may happen
969 simultaneously. This means that there is some risk of session data being
970 overwritten, like this:
976 request a starts, request b starts, with the same session ID
980 session data is loaded in request a
984 session data is loaded in request b
988 session data is changed in request a
992 request a finishes, session data is updated and written to store
996 request b finishes, session data is updated and written to store, overwriting
1001 If this is a concern in your application, a soon-to-be-developed locking
1002 solution is the only safe way to go. This will have a bigger overhead.
1004 For applications where any given user is only making one request at a time this
1005 plugin should be safe enough.
1013 Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
1017 And countless other contributers from #catalyst. Thanks guys!
1019 =head1 COPYRIGHT & LICENSE
1021 Copyright (c) 2005 the aforementioned authors. All rights
1022 reserved. This program is free software; you can redistribute
1023 it and/or modify it under the same terms as Perl itself.