3 package Catalyst::Plugin::Session;
4 use base qw/Class::Accessor::Fast/;
10 use Catalyst::Exception ();
13 use Object::Signature ();
15 our $VERSION = "0.12";
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->_save_session_id;
105 $c->_save_session_expires;
107 $c->_clear_session_instance_data;
109 $c->NEXT::finalize_session;
112 sub _save_session_id {
115 # we already called set when allocating
116 # no need to tell the state plugins anything new
119 sub _save_session_expires {
122 if ( defined($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") 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;
391 sub session_expire_key {
392 my ( $c, %keys ) = @_;
395 @{ $c->session->{__expire_keys} }{ keys %keys } =
396 map { $now + $_ } values %keys;
399 sub initialize_session_data {
410 $c->config->{session}{verify_address}
411 ? ( __address => $c->request->address )
418 sub generate_session_id {
421 my $digest = $c->_find_digest();
422 $digest->add( $c->session_hash_seed() );
423 return $digest->hexdigest;
426 sub create_session_id_if_needed {
428 $c->create_session_id unless $c->sessionid;
431 sub create_session_id {
434 my $sid = $c->generate_session_id;
436 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
438 $c->_sessionid($sid);
439 $c->reset_session_expires;
440 $c->set_session_id($sid);
447 sub session_hash_seed {
450 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
455 sub _find_digest () {
457 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
458 if ( eval { Digest->new($alg) } ) {
463 Catalyst::Exception->throw(
464 "Could not find a suitable Digest module. Please install "
465 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
469 return Digest->new($usable);
476 $c->NEXT::dump_these(),
479 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
485 sub get_session_id { shift->NEXT::get_session_id(@_) }
486 sub set_session_id { shift->NEXT::set_session_id(@_) }
487 sub delete_session_id { shift->NEXT::delete_session_id(@_) }
488 sub extend_session_id { shift->NEXT::extend_session_id(@_) }
498 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
499 storage and client side state required to maintain session data.
503 # To get sessions to "just work", all you need to do is use these plugins:
507 Session::Store::FastMmap
508 Session::State::Cookie
511 # you can replace Store::FastMmap with Store::File - both have sensible
512 # default configurations (see their docs for details)
514 # more complicated backends are available for other scenarios (DBI storage,
518 # after you've loaded the plugins you can save session data
519 # For example, if you are writing a shopping cart, it could be implemented
522 sub add_item : Local {
523 my ( $self, $c ) = @_;
525 my $item_id = $c->req->param("item");
527 # $c->session is a hash ref, a bit like $c->stash
528 # the difference is that it' preserved across requests
530 push @{ $c->session->{items} }, $item_id;
532 $c->forward("MyView");
535 sub display_items : Local {
536 my ( $self, $c ) = @_;
538 # values in $c->session are restored
539 $c->stash->{items_to_display} =
540 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
542 $c->forward("MyView");
547 The Session plugin is the base of two related parts of functionality required
548 for session management in web applications.
550 The first part, the State, is getting the browser to repeat back a session key,
551 so that the web application can identify the client and logically string
552 several requests together into a session.
554 The second part, the Store, deals with the actual storage of information about
555 the client. This data is stored so that the it may be revived for every request
556 made by the same client.
558 This plugin links the two pieces together.
560 =head1 RECCOMENDED BACKENDS
564 =item Session::State::Cookie
566 The only really sane way to do state is using cookies.
568 =item Session::Store::File
570 A portable backend, based on Cache::File.
572 =item Session::Store::FastMmap
574 A fast and flexible backend, based on Cache::FastMmap.
584 An accessor for the session ID value.
588 Returns a hash reference that might contain unserialized values from previous
589 requests in the same session, and whose modified value will be saved for future
592 This method will automatically create a new session and session ID if none
595 =item session_expires
597 =item session_expires $reset
599 This method returns the time when the current session will expire, or 0 if
600 there is no current session. If there is a session and it already expired, it
601 will delete the session and return 0 as well.
603 If the C<$reset> parameter is true, and there is a session ID the expiry time
604 will be reset to the current time plus the time to live (see
605 L</CONFIGURATION>). This is used when creating a new session.
609 This is like Ruby on Rails' flash data structure. Think of it as a stash that
610 lasts for longer than one request, letting you redirect instead of forward.
612 The flash data will be cleaned up only on requests on which actually use
613 $c->flash (thus allowing multiple redirections), and the policy is to delete
614 all the keys which haven't changed since the flash data was loaded at the end
618 my ( $self, $c ) = @_;
620 $c->flash->{beans} = 10;
621 $c->response->redirect( $c->uri_for("foo") );
625 my ( $self, $c ) = @_;
627 my $value = $c->flash->{beans};
631 $c->response->redirect( $c->uri_for("bar") );
635 my ( $self, $c ) = @_;
637 if ( exists $c->flash->{beans} ) { # false
642 =item keep_flash @keys
644 If you wawnt to keep a flash key for the next request too, even if it hasn't
645 changed, call C<keep_flash> and pass in the keys as arguments.
647 =item delete_session REASON
649 This method is used to invalidate a session. It takes an optional parameter
650 which will be saved in C<session_delete_reason> if provided.
652 =item session_delete_reason
654 This accessor contains a string with the reason a session was deleted. Possible
669 =item session_expire_key $key, $ttl
671 Mark a key to expire at a certain time (only useful when shorter than the
672 expiry time for the whole session).
676 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
680 $c->session_expire_key( __user => 3600 );
682 Will make the session data survive, but the user will still be logged out after
685 Note that these values are not auto extended.
689 =head1 INTERNAL METHODS
695 This method is extended to also make calls to
696 C<check_session_plugin_requirements> and C<setup_session>.
698 =item check_session_plugin_requirements
700 This method ensures that a State and a Store plugin are also in use by the
705 This method populates C<< $c->config->{session} >> with the default values
706 listed in L</CONFIGURATION>.
710 This methoid is extended.
712 It's only effect is if the (off by default) C<flash_to_stash> configuration
713 parameter is on - then it will copy the contents of the flash to the stash at
718 This method is extended and will extend the expiry time, as well as persist the
719 session data if a session exists.
721 =item initialize_session_data
723 This method will initialize the internal structure of the session, and is
724 called by the C<session> method if appropriate.
726 =item create_session_id
728 Creates a new session id using C<generate_session_id> if there is no session ID
731 =item validate_session_id SID
733 Make sure a session ID is of the right format.
735 This currently ensures that the session ID string is any amount of case
736 insensitive hexadecimal characters.
738 =item generate_session_id
740 This method will return a string that can be used as a session ID. It is
741 supposed to be a reasonably random string with enough bits to prevent
742 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
743 MD5 or SHA-256, depending on the availibility of these modules.
745 =item session_hash_seed
747 This method is actually rather internal to generate_session_id, but should be
748 overridable in case you want to provide more random data.
750 Currently it returns a concatenated string which contains:
764 One value from C<rand>.
768 The stringified value of a newly allocated hash reference
772 The stringified value of the Catalyst context object
776 In the hopes that those combined values are entropic enough for most uses. If
777 this is not the case you can replace C<session_hash_seed> with e.g.
779 sub session_hash_seed {
780 open my $fh, "<", "/dev/random";
781 read $fh, my $bytes, 20;
786 Or even more directly, replace C<generate_session_id>:
788 sub generate_session_id {
789 open my $fh, "<", "/dev/random";
790 read $fh, my $bytes, 20;
792 return unpack("H*", $bytes);
795 Also have a look at L<Crypt::Random> and the various openssl bindings - these
796 modules provide APIs for cryptographically secure random data.
798 =item finalize_session
800 Clean up the session during C<finalize>.
802 This clears the various accessors after saving to the store.
806 See L<Catalyst/dump_these> - ammends the session data structure to the list of
807 dumped objects if session ID is defined.
811 =head1 USING SESSIONS DURING PREPARE
813 The earliest point in time at which you may use the session data is after
814 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
816 State plugins must set $c->session ID before C<prepare_action>, and during
817 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
823 # don't touch $c->session yet!
825 $c->NEXT::prepare_action( @_ );
827 $c->session; # this is OK
828 $c->sessionid; # this is also OK
833 $c->config->{session} = {
837 All configuation parameters are provided in a hash reference under the
838 C<session> key in the configuration hash.
844 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
849 When true, C<<$c->request->address>> will be checked at prepare time. If it is
850 not the same as the address that initiated the session, the session is deleted.
854 This option makes it easier to have actions behave the same whether they were
855 forwarded to or redirected to. On prepare time it copies the contents of
856 C<flash> (if any) to the stash.
862 The hash reference returned by C<< $c->session >> contains several keys which
863 are automatically set:
869 This key no longer exists. Use C<session_expires> instead.
873 The last time a session was saved to the store.
877 The time when the session was first created.
881 The value of C<< $c->request->address >> at the time the session was created.
882 This value is only populated if C<verify_address> is true in the configuration.
888 =head2 Round the Robin Proxies
890 C<verify_address> could make your site inaccessible to users who are behind
891 load balanced proxies. Some ISPs may give a different IP to each request by the
892 same client due to this type of proxying. If addresses are verified these
893 users' sessions cannot persist.
895 To let these users access your site you can either disable address verification
896 as a whole, or provide a checkbox in the login dialog that tells the server
897 that it's OK for the address of the client to change. When the server sees that
898 this box is checked it should delete the C<__address> sepcial key from the
899 session hash when the hash is first created.
901 =head2 Race Conditions
903 In this day and age where cleaning detergents and dutch football (not the
904 american kind) teams roam the plains in great numbers, requests may happen
905 simultaneously. This means that there is some risk of session data being
906 overwritten, like this:
912 request a starts, request b starts, with the same session id
916 session data is loaded in request a
920 session data is loaded in request b
924 session data is changed in request a
928 request a finishes, session data is updated and written to store
932 request b finishes, session data is updated and written to store, overwriting
937 If this is a concern in your application, a soon to be developed locking
938 solution is the only safe way to go. This will have a bigger overhead.
940 For applications where any given user is only making one request at a time this
941 plugin should be safe enough.
949 =item Christian Hansen
951 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
953 =item Sebastian Riedel
957 And countless other contributers from #catalyst. Thanks guys!
959 =head1 COPYRIGHT & LICENSE
961 Copyright (c) 2005 the aforementioned authors. All rights
962 reserved. This program is free software; you can redistribute
963 it and/or modify it under the same terms as Perl itself.