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 $c->create_session_id_if_needed;
394 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
395 $c->_flash_key_hashes({});
396 $c->_flash_keep_keys({});
400 sub session_expire_key {
401 my ( $c, %keys ) = @_;
404 @{ $c->session->{__expire_keys} }{ keys %keys } =
405 map { $now + $_ } values %keys;
408 sub initialize_session_data {
419 $c->config->{session}{verify_address}
420 ? ( __address => $c->request->address )
427 sub generate_session_id {
430 my $digest = $c->_find_digest();
431 $digest->add( $c->session_hash_seed() );
432 return $digest->hexdigest;
435 sub create_session_id_if_needed {
437 $c->create_session_id unless $c->sessionid;
440 sub create_session_id {
443 my $sid = $c->generate_session_id;
445 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
447 $c->_sessionid($sid);
448 $c->reset_session_expires;
449 $c->set_session_id($sid);
456 sub session_hash_seed {
459 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
464 sub _find_digest () {
466 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
467 if ( eval { Digest->new($alg) } ) {
472 Catalyst::Exception->throw(
473 "Could not find a suitable Digest module. Please install "
474 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
478 return Digest->new($usable);
485 $c->NEXT::dump_these(),
488 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
494 sub get_session_id { shift->NEXT::get_session_id(@_) }
495 sub set_session_id { shift->NEXT::set_session_id(@_) }
496 sub delete_session_id { shift->NEXT::delete_session_id(@_) }
497 sub extend_session_id { shift->NEXT::extend_session_id(@_) }
507 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
508 storage and client side state required to maintain session data.
512 # To get sessions to "just work", all you need to do is use these plugins:
516 Session::Store::FastMmap
517 Session::State::Cookie
520 # you can replace Store::FastMmap with Store::File - both have sensible
521 # default configurations (see their docs for details)
523 # more complicated backends are available for other scenarios (DBI storage,
527 # after you've loaded the plugins you can save session data
528 # For example, if you are writing a shopping cart, it could be implemented
531 sub add_item : Local {
532 my ( $self, $c ) = @_;
534 my $item_id = $c->req->param("item");
536 # $c->session is a hash ref, a bit like $c->stash
537 # the difference is that it' preserved across requests
539 push @{ $c->session->{items} }, $item_id;
541 $c->forward("MyView");
544 sub display_items : Local {
545 my ( $self, $c ) = @_;
547 # values in $c->session are restored
548 $c->stash->{items_to_display} =
549 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
551 $c->forward("MyView");
556 The Session plugin is the base of two related parts of functionality required
557 for session management in web applications.
559 The first part, the State, is getting the browser to repeat back a session key,
560 so that the web application can identify the client and logically string
561 several requests together into a session.
563 The second part, the Store, deals with the actual storage of information about
564 the client. This data is stored so that the it may be revived for every request
565 made by the same client.
567 This plugin links the two pieces together.
569 =head1 RECCOMENDED BACKENDS
573 =item Session::State::Cookie
575 The only really sane way to do state is using cookies.
577 =item Session::Store::File
579 A portable backend, based on Cache::File.
581 =item Session::Store::FastMmap
583 A fast and flexible backend, based on Cache::FastMmap.
593 An accessor for the session ID value.
597 Returns a hash reference that might contain unserialized values from previous
598 requests in the same session, and whose modified value will be saved for future
601 This method will automatically create a new session and session ID if none
604 =item session_expires
606 =item session_expires $reset
608 This method returns the time when the current session will expire, or 0 if
609 there is no current session. If there is a session and it already expired, it
610 will delete the session and return 0 as well.
612 If the C<$reset> parameter is true, and there is a session ID the expiry time
613 will be reset to the current time plus the time to live (see
614 L</CONFIGURATION>). This is used when creating a new session.
618 This is like Ruby on Rails' flash data structure. Think of it as a stash that
619 lasts for longer than one request, letting you redirect instead of forward.
621 The flash data will be cleaned up only on requests on which actually use
622 $c->flash (thus allowing multiple redirections), and the policy is to delete
623 all the keys which haven't changed since the flash data was loaded at the end
627 my ( $self, $c ) = @_;
629 $c->flash->{beans} = 10;
630 $c->response->redirect( $c->uri_for("foo") );
634 my ( $self, $c ) = @_;
636 my $value = $c->flash->{beans};
640 $c->response->redirect( $c->uri_for("bar") );
644 my ( $self, $c ) = @_;
646 if ( exists $c->flash->{beans} ) { # false
653 Zap all the keys in the flash regardless of their current state.
655 =item keep_flash @keys
657 If you wawnt to keep a flash key for the next request too, even if it hasn't
658 changed, call C<keep_flash> and pass in the keys as arguments.
660 =item delete_session REASON
662 This method is used to invalidate a session. It takes an optional parameter
663 which will be saved in C<session_delete_reason> if provided.
665 =item session_delete_reason
667 This accessor contains a string with the reason a session was deleted. Possible
682 =item session_expire_key $key, $ttl
684 Mark a key to expire at a certain time (only useful when shorter than the
685 expiry time for the whole session).
689 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
693 $c->session_expire_key( __user => 3600 );
695 Will make the session data survive, but the user will still be logged out after
698 Note that these values are not auto extended.
702 =head1 INTERNAL METHODS
708 This method is extended to also make calls to
709 C<check_session_plugin_requirements> and C<setup_session>.
711 =item check_session_plugin_requirements
713 This method ensures that a State and a Store plugin are also in use by the
718 This method populates C<< $c->config->{session} >> with the default values
719 listed in L</CONFIGURATION>.
723 This methoid is extended.
725 It's only effect is if the (off by default) C<flash_to_stash> configuration
726 parameter is on - then it will copy the contents of the flash to the stash at
731 This method is extended and will extend the expiry time, as well as persist the
732 session data if a session exists.
734 =item initialize_session_data
736 This method will initialize the internal structure of the session, and is
737 called by the C<session> method if appropriate.
739 =item create_session_id
741 Creates a new session id using C<generate_session_id> if there is no session ID
744 =item validate_session_id SID
746 Make sure a session ID is of the right format.
748 This currently ensures that the session ID string is any amount of case
749 insensitive hexadecimal characters.
751 =item generate_session_id
753 This method will return a string that can be used as a session ID. It is
754 supposed to be a reasonably random string with enough bits to prevent
755 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
756 MD5 or SHA-256, depending on the availibility of these modules.
758 =item session_hash_seed
760 This method is actually rather internal to generate_session_id, but should be
761 overridable in case you want to provide more random data.
763 Currently it returns a concatenated string which contains:
777 One value from C<rand>.
781 The stringified value of a newly allocated hash reference
785 The stringified value of the Catalyst context object
789 In the hopes that those combined values are entropic enough for most uses. If
790 this is not the case you can replace C<session_hash_seed> with e.g.
792 sub session_hash_seed {
793 open my $fh, "<", "/dev/random";
794 read $fh, my $bytes, 20;
799 Or even more directly, replace C<generate_session_id>:
801 sub generate_session_id {
802 open my $fh, "<", "/dev/random";
803 read $fh, my $bytes, 20;
805 return unpack("H*", $bytes);
808 Also have a look at L<Crypt::Random> and the various openssl bindings - these
809 modules provide APIs for cryptographically secure random data.
811 =item finalize_session
813 Clean up the session during C<finalize>.
815 This clears the various accessors after saving to the store.
819 See L<Catalyst/dump_these> - ammends the session data structure to the list of
820 dumped objects if session ID is defined.
824 =head1 USING SESSIONS DURING PREPARE
826 The earliest point in time at which you may use the session data is after
827 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
829 State plugins must set $c->session ID before C<prepare_action>, and during
830 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
836 # don't touch $c->session yet!
838 $c->NEXT::prepare_action( @_ );
840 $c->session; # this is OK
841 $c->sessionid; # this is also OK
846 $c->config->{session} = {
850 All configuation parameters are provided in a hash reference under the
851 C<session> key in the configuration hash.
857 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
862 When true, C<<$c->request->address>> will be checked at prepare time. If it is
863 not the same as the address that initiated the session, the session is deleted.
867 This option makes it easier to have actions behave the same whether they were
868 forwarded to or redirected to. On prepare time it copies the contents of
869 C<flash> (if any) to the stash.
875 The hash reference returned by C<< $c->session >> contains several keys which
876 are automatically set:
882 This key no longer exists. Use C<session_expires> instead.
886 The last time a session was saved to the store.
890 The time when the session was first created.
894 The value of C<< $c->request->address >> at the time the session was created.
895 This value is only populated if C<verify_address> is true in the configuration.
901 =head2 Round the Robin Proxies
903 C<verify_address> could make your site inaccessible to users who are behind
904 load balanced proxies. Some ISPs may give a different IP to each request by the
905 same client due to this type of proxying. If addresses are verified these
906 users' sessions cannot persist.
908 To let these users access your site you can either disable address verification
909 as a whole, or provide a checkbox in the login dialog that tells the server
910 that it's OK for the address of the client to change. When the server sees that
911 this box is checked it should delete the C<__address> sepcial key from the
912 session hash when the hash is first created.
914 =head2 Race Conditions
916 In this day and age where cleaning detergents and dutch football (not the
917 american kind) teams roam the plains in great numbers, requests may happen
918 simultaneously. This means that there is some risk of session data being
919 overwritten, like this:
925 request a starts, request b starts, with the same session id
929 session data is loaded in request a
933 session data is loaded in request b
937 session data is changed in request a
941 request a finishes, session data is updated and written to store
945 request b finishes, session data is updated and written to store, overwriting
950 If this is a concern in your application, a soon to be developed locking
951 solution is the only safe way to go. This will have a bigger overhead.
953 For applications where any given user is only making one request at a time this
954 plugin should be safe enough.
962 =item Christian Hansen
964 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
966 =item Sebastian Riedel
970 And countless other contributers from #catalyst. Thanks guys!
972 =head1 COPYRIGHT & LICENSE
974 Copyright (c) 2005 the aforementioned authors. All rights
975 reserved. This program is free software; you can redistribute
976 it and/or modify it under the same terms as Perl itself.