3 package Catalyst::Plugin::Session;
4 use base qw/Class::Accessor::Fast/;
10 use Catalyst::Exception ();
13 use Object::Signature ();
16 our $VERSION = "0.16";
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 $c->NEXT::finalize(@_);
100 sub finalize_session {
103 $c->NEXT::finalize_session;
105 $c->_save_session_id;
108 $c->_save_session_expires;
110 $c->_clear_session_instance_data;
113 sub _save_session_id {
116 # we already called set when allocating
117 # no need to tell the state plugins anything new
120 sub _save_session_expires {
123 if ( defined($c->_session_expires) ) {
124 my $expires = $c->session_expires; # force extension
126 my $sid = $c->sessionid;
127 $c->store_session_data( "expires:$sid" => $expires );
134 if ( my $session_data = $c->_session ) {
136 no warnings 'uninitialized';
137 if ( Object::Signature::signature($session_data) ne
138 $c->_session_data_sig )
140 $session_data->{__updated} = time();
141 my $sid = $c->sessionid;
142 $c->store_session_data( "session:$sid" => $session_data );
150 if ( my $flash_data = $c->_flash ) {
152 my $hashes = $c->_flash_key_hashes || {};
153 my $keep = $c->_flash_keep_keys || {};
154 foreach my $key ( keys %$hashes ) {
155 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
156 delete $flash_data->{$key};
160 my $sid = $c->sessionid;
163 $c->store_session_data( "flash:$sid", $flash_data );
166 $c->delete_session_data("flash:$sid");
171 sub _load_session_expires {
173 return $c->_session_expires if $c->_tried_loading_session_expires;
174 $c->_tried_loading_session_expires(1);
176 if ( my $sid = $c->sessionid ) {
177 my $expires = $c->get_session_data("expires:$sid") || 0;
179 if ( $expires >= time() ) {
180 $c->_session_expires( $expires );
183 $c->delete_session( "session expired" );
193 return $c->_session if $c->_tried_loading_session_data;
194 $c->_tried_loading_session_data(1);
196 if ( my $sid = $c->sessionid ) {
197 if ( $c->_load_session_expires ) { # > 0
199 my $session_data = $c->get_session_data("session:$sid") || return;
200 $c->_session($session_data);
202 no warnings 'uninitialized'; # ne __address
203 if ( $c->config->{session}{verify_address}
204 && $session_data->{__address} ne $c->request->address )
207 "Deleting session $sid due to address mismatch ("
208 . $session_data->{__address} . " != "
209 . $c->request->address . ")"
211 $c->delete_session("address mismatch");
215 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
216 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
217 $c->_expire_session_keys;
219 return $session_data;
228 return $c->_flash if $c->_tried_loading_flash_data;
229 $c->_tried_loading_flash_data(1);
231 if ( my $sid = $c->sessionid ) {
232 if ( my $flash_data = $c->_flash
233 || $c->_flash( $c->get_session_data("flash:$sid") ) )
235 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
244 sub _expire_session_keys {
245 my ( $c, $data ) = @_;
249 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
250 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
251 delete $c->_session->{$key};
252 delete $expire_times->{$key};
256 sub _clear_session_instance_data {
258 $c->$_(undef) for @session_data_accessors;
259 $c->NEXT::_clear_session_instance_data; # allow other plugins to hook in on this
263 my ( $c, $msg ) = @_;
265 $c->log->debug("Deleting session" . ( defined($msg) ? "($msg)" : '(no reason given)') ) if $c->debug;
267 # delete the session data
268 if ( my $sid = $c->sessionid ) {
269 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
270 $c->delete_session_id($sid);
273 # reset the values in the context object
274 # see the BEGIN block
275 $c->_clear_session_instance_data;
277 $c->_session_delete_reason($msg);
280 sub session_delete_reason {
283 $c->session_is_valid; # check that it was loaded
285 $c->_session_delete_reason(@_);
288 sub session_expires {
291 if ( defined( my $expires = $c->_extended_session_expires ) ) {
293 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
294 return $c->extend_session_expires( $expires );
300 sub extend_session_expires {
301 my ( $c, $expires ) = @_;
302 $c->_extended_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
303 $c->extend_session_id( $c->sessionid, $updated );
307 sub calculate_initial_session_expires {
309 return ( time() + $c->config->{session}{expires} );
312 sub calculate_extended_session_expires {
313 my ( $c, $prev ) = @_;
314 $c->calculate_initial_session_expires;
317 sub reset_session_expires {
318 my ( $c, $sid ) = @_;
320 my $exp = $c->calculate_initial_session_expires;
321 $c->_session_expires( $exp );
322 $c->_extended_session_expires( $exp );
329 return $c->_sessionid || $c->_load_sessionid;
332 sub _load_sessionid {
334 return if $c->_tried_loading_session_id;
335 $c->_tried_loading_session_id(1);
337 if ( defined( my $sid = $c->get_session_id ) ) {
338 if ( $c->validate_session_id($sid) ) {
339 # temporarily set the inner key, so that validation will work
340 $c->_sessionid($sid);
343 my $err = "Tried to set invalid session ID '$sid'";
344 $c->log->error($err);
345 Catalyst::Exception->throw($err);
352 sub session_is_valid {
355 # force a check for expiry, but also __address, etc
356 if ( $c->_load_session ) {
363 sub validate_session_id {
364 my ( $c, $sid ) = @_;
366 $sid and $sid =~ /^[a-f\d]+$/i;
372 $c->_session || $c->_load_session || do {
373 $c->create_session_id_if_needed;
374 $c->initialize_session_data;
379 my ( $c, @keys ) = @_;
380 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
381 (@{$href}{@keys}) = ((undef) x @keys);
386 $c->_flash || $c->_load_flash || do {
387 $c->create_session_id_if_needed;
395 my $items = @_ > 1 ? {@_} : $_[0];
396 croak('flash takes a hash or hashref') unless ref $items;
397 @{ $c->_flash }{ keys %$items } = values %$items;
411 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
412 $c->_flash_key_hashes({});
413 $c->_flash_keep_keys({});
417 sub session_expire_key {
418 my ( $c, %keys ) = @_;
421 @{ $c->session->{__expire_keys} }{ keys %keys } =
422 map { $now + $_ } values %keys;
425 sub initialize_session_data {
436 $c->config->{session}{verify_address}
437 ? ( __address => $c->request->address )
444 sub generate_session_id {
447 my $digest = $c->_find_digest();
448 $digest->add( $c->session_hash_seed() );
449 return $digest->hexdigest;
452 sub create_session_id_if_needed {
454 $c->create_session_id unless $c->sessionid;
457 sub create_session_id {
460 my $sid = $c->generate_session_id;
462 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
464 $c->_sessionid($sid);
465 $c->reset_session_expires;
466 $c->set_session_id($sid);
473 sub session_hash_seed {
476 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
481 sub _find_digest () {
483 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
484 if ( eval { Digest->new($alg) } ) {
489 Catalyst::Exception->throw(
490 "Could not find a suitable Digest module. Please install "
491 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
495 return Digest->new($usable);
502 $c->NEXT::dump_these(),
505 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
511 sub get_session_id { shift->NEXT::get_session_id(@_) }
512 sub set_session_id { shift->NEXT::set_session_id(@_) }
513 sub delete_session_id { shift->NEXT::delete_session_id(@_) }
514 sub extend_session_id { shift->NEXT::extend_session_id(@_) }
524 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
525 storage and client side state required to maintain session data.
529 # To get sessions to "just work", all you need to do is use these plugins:
533 Session::Store::FastMmap
534 Session::State::Cookie
537 # you can replace Store::FastMmap with Store::File - both have sensible
538 # default configurations (see their docs for details)
540 # more complicated backends are available for other scenarios (DBI storage,
544 # after you've loaded the plugins you can save session data
545 # For example, if you are writing a shopping cart, it could be implemented
548 sub add_item : Local {
549 my ( $self, $c ) = @_;
551 my $item_id = $c->req->param("item");
553 # $c->session is a hash ref, a bit like $c->stash
554 # the difference is that it' preserved across requests
556 push @{ $c->session->{items} }, $item_id;
558 $c->forward("MyView");
561 sub display_items : Local {
562 my ( $self, $c ) = @_;
564 # values in $c->session are restored
565 $c->stash->{items_to_display} =
566 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
568 $c->forward("MyView");
573 The Session plugin is the base of two related parts of functionality required
574 for session management in web applications.
576 The first part, the State, is getting the browser to repeat back a session key,
577 so that the web application can identify the client and logically string
578 several requests together into a session.
580 The second part, the Store, deals with the actual storage of information about
581 the client. This data is stored so that the it may be revived for every request
582 made by the same client.
584 This plugin links the two pieces together.
586 =head1 RECOMENDED BACKENDS
590 =item Session::State::Cookie
592 The only really sane way to do state is using cookies.
594 =item Session::Store::File
596 A portable backend, based on Cache::File.
598 =item Session::Store::FastMmap
600 A fast and flexible backend, based on Cache::FastMmap.
610 An accessor for the session ID value.
614 Returns a hash reference that might contain unserialized values from previous
615 requests in the same session, and whose modified value will be saved for future
618 This method will automatically create a new session and session ID if none
621 =item session_expires
623 =item session_expires $reset
625 This method returns the time when the current session will expire, or 0 if
626 there is no current session. If there is a session and it already expired, it
627 will delete the session and return 0 as well.
629 If the C<$reset> parameter is true, and there is a session ID the expiry time
630 will be reset to the current time plus the time to live (see
631 L</CONFIGURATION>). This is used when creating a new session.
635 This is like Ruby on Rails' flash data structure. Think of it as a stash that
636 lasts for longer than one request, letting you redirect instead of forward.
638 The flash data will be cleaned up only on requests on which actually use
639 $c->flash (thus allowing multiple redirections), and the policy is to delete
640 all the keys which haven't changed since the flash data was loaded at the end
644 my ( $self, $c ) = @_;
646 $c->flash->{beans} = 10;
647 $c->response->redirect( $c->uri_for("foo") );
651 my ( $self, $c ) = @_;
653 my $value = $c->flash->{beans};
657 $c->response->redirect( $c->uri_for("bar") );
661 my ( $self, $c ) = @_;
663 if ( exists $c->flash->{beans} ) { # false
670 Zap all the keys in the flash regardless of their current state.
672 =item keep_flash @keys
674 If you wawnt to keep a flash key for the next request too, even if it hasn't
675 changed, call C<keep_flash> and pass in the keys as arguments.
677 =item delete_session REASON
679 This method is used to invalidate a session. It takes an optional parameter
680 which will be saved in C<session_delete_reason> if provided.
682 =item session_delete_reason
684 This accessor contains a string with the reason a session was deleted. Possible
699 =item session_expire_key $key, $ttl
701 Mark a key to expire at a certain time (only useful when shorter than the
702 expiry time for the whole session).
706 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
710 $c->session_expire_key( __user => 3600 );
712 Will make the session data survive, but the user will still be logged out after
715 Note that these values are not auto extended.
719 =head1 INTERNAL METHODS
725 This method is extended to also make calls to
726 C<check_session_plugin_requirements> and C<setup_session>.
728 =item check_session_plugin_requirements
730 This method ensures that a State and a Store plugin are also in use by the
735 This method populates C<< $c->config->{session} >> with the default values
736 listed in L</CONFIGURATION>.
740 This methoid is extended.
742 It's only effect is if the (off by default) C<flash_to_stash> configuration
743 parameter is on - then it will copy the contents of the flash to the stash at
748 This method is extended and will extend the expiry time, as well as persist the
749 session data if a session exists.
751 =item initialize_session_data
753 This method will initialize the internal structure of the session, and is
754 called by the C<session> method if appropriate.
756 =item create_session_id
758 Creates a new session id using C<generate_session_id> if there is no session ID
761 =item validate_session_id SID
763 Make sure a session ID is of the right format.
765 This currently ensures that the session ID string is any amount of case
766 insensitive hexadecimal characters.
768 =item generate_session_id
770 This method will return a string that can be used as a session ID. It is
771 supposed to be a reasonably random string with enough bits to prevent
772 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
773 MD5 or SHA-256, depending on the availibility of these modules.
775 =item session_hash_seed
777 This method is actually rather internal to generate_session_id, but should be
778 overridable in case you want to provide more random data.
780 Currently it returns a concatenated string which contains:
794 One value from C<rand>.
798 The stringified value of a newly allocated hash reference
802 The stringified value of the Catalyst context object
806 In the hopes that those combined values are entropic enough for most uses. If
807 this is not the case you can replace C<session_hash_seed> with e.g.
809 sub session_hash_seed {
810 open my $fh, "<", "/dev/random";
811 read $fh, my $bytes, 20;
816 Or even more directly, replace C<generate_session_id>:
818 sub generate_session_id {
819 open my $fh, "<", "/dev/random";
820 read $fh, my $bytes, 20;
822 return unpack("H*", $bytes);
825 Also have a look at L<Crypt::Random> and the various openssl bindings - these
826 modules provide APIs for cryptographically secure random data.
828 =item finalize_session
830 Clean up the session during C<finalize>.
832 This clears the various accessors after saving to the store.
836 See L<Catalyst/dump_these> - ammends the session data structure to the list of
837 dumped objects if session ID is defined.
841 =head1 USING SESSIONS DURING PREPARE
843 The earliest point in time at which you may use the session data is after
844 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
846 State plugins must set $c->session ID before C<prepare_action>, and during
847 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
853 # don't touch $c->session yet!
855 $c->NEXT::prepare_action( @_ );
857 $c->session; # this is OK
858 $c->sessionid; # this is also OK
863 $c->config->{session} = {
867 All configuation parameters are provided in a hash reference under the
868 C<session> key in the configuration hash.
874 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
879 When true, C<<$c->request->address>> will be checked at prepare time. If it is
880 not the same as the address that initiated the session, the session is deleted.
886 This option makes it easier to have actions behave the same whether they were
887 forwarded to or redirected to. On prepare time it copies the contents of
888 C<flash> (if any) to the stash.
894 The hash reference returned by C<< $c->session >> contains several keys which
895 are automatically set:
901 This key no longer exists. Use C<session_expires> instead.
905 The last time a session was saved to the store.
909 The time when the session was first created.
913 The value of C<< $c->request->address >> at the time the session was created.
914 This value is only populated if C<verify_address> is true in the configuration.
920 =head2 Round the Robin Proxies
922 C<verify_address> could make your site inaccessible to users who are behind
923 load balanced proxies. Some ISPs may give a different IP to each request by the
924 same client due to this type of proxying. If addresses are verified these
925 users' sessions cannot persist.
927 To let these users access your site you can either disable address verification
928 as a whole, or provide a checkbox in the login dialog that tells the server
929 that it's OK for the address of the client to change. When the server sees that
930 this box is checked it should delete the C<__address> sepcial key from the
931 session hash when the hash is first created.
933 =head2 Race Conditions
935 In this day and age where cleaning detergents and dutch football (not the
936 american kind) teams roam the plains in great numbers, requests may happen
937 simultaneously. This means that there is some risk of session data being
938 overwritten, like this:
944 request a starts, request b starts, with the same session id
948 session data is loaded in request a
952 session data is loaded in request b
956 session data is changed in request a
960 request a finishes, session data is updated and written to store
964 request b finishes, session data is updated and written to store, overwriting
969 If this is a concern in your application, a soon to be developed locking
970 solution is the only safe way to go. This will have a bigger overhead.
972 For applications where any given user is only making one request at a time this
973 plugin should be safe enough.
981 =item Christian Hansen
983 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
985 =item Sebastian Riedel
989 And countless other contributers from #catalyst. Thanks guys!
991 =head1 COPYRIGHT & LICENSE
993 Copyright (c) 2005 the aforementioned authors. All rights
994 reserved. This program is free software; you can redistribute
995 it and/or modify it under the same terms as Perl itself.