3 package Catalyst::Plugin::Session;
6 with 'MooseX::Emulate::Class::Accessor::Fast';
8 use Catalyst::Exception ();
11 use Object::Signature ();
14 use namespace::clean -except => 'meta';
16 our $VERSION = '0.34';
17 $VERSION = eval $VERSION;
19 my @session_data_accessors; # used in delete_session
21 __PACKAGE__->mk_accessors(
22 "_session_delete_reason",
23 @session_data_accessors = qw/
27 _extended_session_expires
32 _tried_loading_session_id
33 _tried_loading_session_data
34 _tried_loading_session_expires
35 _tried_loading_flash_data
39 sub _session_plugin_config {
41 # FIXME - Start warning once all the state/store modules have also been updated.
42 #$c->log->warn("Deprecated 'session' config key used, please use the key 'Plugin::Session' instead")
43 # if exists $c->config->{session}
44 #$c->config->{'Plugin::Session'} ||= delete($c->config->{session}) || {};
45 $c->config->{'Plugin::Session'} ||= $c->config->{session} || {};
51 $c->maybe::next::method(@_);
53 $c->check_session_plugin_requirements;
59 sub check_session_plugin_requirements {
62 unless ( $c->isa("Catalyst::Plugin::Session::State")
63 && $c->isa("Catalyst::Plugin::Session::Store") )
66 ( "The Session plugin requires both Session::State "
67 . "and Session::Store plugins to be used as well." );
70 Catalyst::Exception->throw($err);
77 my $cfg = $c->_session_plugin_config;
82 verify_user_agent => 0,
86 $c->maybe::next::method();
92 $c->maybe::next::method(@_);
94 if ( $c->_session_plugin_config->{flash_to_stash}
96 and my $flash_data = $c->flash )
98 @{ $c->stash }{ keys %$flash_data } = values %$flash_data;
102 sub finalize_headers {
105 # Force extension of session_expires before finalizing headers, so a possible cookie will be
106 # up to date. First call to session_expires will extend the expiry, subsequent calls will
107 # just return the previously extended value.
110 return $c->maybe::next::method(@_);
116 # We have to finalize our session *before* $c->engine->finalize_xxx is called,
117 # because we do not want to send the HTTP response before the session is stored/committed to
118 # the session database (or whatever Session::Store you use).
119 $c->finalize_session;
121 return $c->maybe::next::method(@_);
124 sub finalize_session {
127 $c->maybe::next::method(@_);
129 $c->_save_session_expires;
130 $c->_save_session_id;
134 $c->_clear_session_instance_data;
137 sub _save_session_id {
140 # we already called set when allocating
141 # no need to tell the state plugins anything new
144 sub _save_session_expires {
147 if ( defined($c->_session_expires) ) {
148 my $expires = $c->session_expires; # force extension
150 my $sid = $c->sessionid;
151 $c->store_session_data( "expires:$sid" => $expires );
158 if ( my $session_data = $c->_session ) {
160 no warnings 'uninitialized';
161 if ( Object::Signature::signature($session_data) ne
162 $c->_session_data_sig )
164 $session_data->{__updated} = time();
165 my $sid = $c->sessionid;
166 $c->store_session_data( "session:$sid" => $session_data );
174 if ( my $flash_data = $c->_flash ) {
176 my $hashes = $c->_flash_key_hashes || {};
177 my $keep = $c->_flash_keep_keys || {};
178 foreach my $key ( keys %$hashes ) {
179 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
180 delete $flash_data->{$key};
184 my $sid = $c->sessionid;
186 my $session_data = $c->_session;
188 $session_data->{__flash} = $flash_data;
191 delete $session_data->{__flash};
193 $c->_session($session_data);
198 sub _load_session_expires {
200 return $c->_session_expires if $c->_tried_loading_session_expires;
201 $c->_tried_loading_session_expires(1);
203 if ( my $sid = $c->sessionid ) {
204 my $expires = $c->get_session_data("expires:$sid") || 0;
206 if ( $expires >= time() ) {
207 $c->_session_expires( $expires );
210 $c->delete_session( "session expired" );
220 return $c->_session if $c->_tried_loading_session_data;
221 $c->_tried_loading_session_data(1);
223 if ( my $sid = $c->sessionid ) {
224 if ( $c->_load_session_expires ) { # > 0
226 my $session_data = $c->get_session_data("session:$sid") || return;
227 $c->_session($session_data);
229 no warnings 'uninitialized'; # ne __address
230 if ( $c->_session_plugin_config->{verify_address}
231 && exists $session_data->{__address}
232 && $session_data->{__address} ne $c->request->address )
235 "Deleting session $sid due to address mismatch ("
236 . $session_data->{__address} . " != "
237 . $c->request->address . ")"
239 $c->delete_session("address mismatch");
242 if ( $c->_session_plugin_config->{verify_user_agent}
243 && $session_data->{__user_agent} ne $c->request->user_agent )
246 "Deleting session $sid due to user agent mismatch ("
247 . $session_data->{__user_agent} . " != "
248 . $c->request->user_agent . ")"
250 $c->delete_session("user agent mismatch");
254 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
255 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
256 $c->_expire_session_keys;
258 return $session_data;
267 return $c->_flash if $c->_tried_loading_flash_data;
268 $c->_tried_loading_flash_data(1);
270 if ( my $sid = $c->sessionid ) {
272 my $session_data = $c->session;
273 $c->_flash($session_data->{__flash});
275 if ( my $flash_data = $c->_flash )
277 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
286 sub _expire_session_keys {
287 my ( $c, $data ) = @_;
291 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
292 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
293 delete $c->_session->{$key};
294 delete $expire_times->{$key};
298 sub _clear_session_instance_data {
300 $c->$_(undef) for @session_data_accessors;
301 $c->maybe::next::method(@_); # allow other plugins to hook in on this
304 sub change_session_id {
307 my $sessiondata = $c->session;
308 my $oldsid = $c->sessionid;
309 my $newsid = $c->create_session_id;
312 $c->log->debug(qq/change_sessid: deleting session data from "$oldsid"/) if $c->debug;
313 $c->delete_session_data("${_}:${oldsid}") for qw/session expires flash/;
316 $c->log->debug(qq/change_sessid: storing session data to "$newsid"/) if $c->debug;
317 $c->store_session_data( "session:$newsid" => $sessiondata );
323 my ( $c, $msg ) = @_;
325 $c->log->debug("Deleting session" . ( defined($msg) ? "($msg)" : '(no reason given)') ) if $c->debug;
327 # delete the session data
328 if ( my $sid = $c->sessionid ) {
329 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
330 $c->delete_session_id($sid);
333 # reset the values in the context object
334 # see the BEGIN block
335 $c->_clear_session_instance_data;
337 $c->_session_delete_reason($msg);
340 sub session_delete_reason {
343 $c->session_is_valid; # check that it was loaded
345 $c->_session_delete_reason(@_);
348 sub session_expires {
351 if ( defined( my $expires = $c->_extended_session_expires ) ) {
353 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
354 return $c->extend_session_expires( $expires );
360 sub extend_session_expires {
361 my ( $c, $expires ) = @_;
362 $c->_extended_session_expires( my $updated = $c->calculate_initial_session_expires( $expires ) );
363 $c->extend_session_id( $c->sessionid, $updated );
367 sub change_session_expires {
368 my ( $c, $expires ) = @_;
371 my $sid = $c->sessionid;
372 my $time_exp = time() + $expires;
373 $c->store_session_data( "expires:$sid" => $time_exp );
376 sub initial_session_expires {
378 return ( time() + $c->_session_plugin_config->{expires} );
381 sub calculate_initial_session_expires {
384 my $initial_expires = $c->initial_session_expires;
385 my $stored_session_expires = 0;
386 if ( my $sid = $c->sessionid ) {
387 $stored_session_expires = $c->get_session_data("expires:$sid") || 0;
389 return ( $initial_expires > $stored_session_expires ) ? $initial_expires : $stored_session_expires;
392 sub calculate_extended_session_expires {
393 my ( $c, $prev ) = @_;
394 return ( time() + $prev );
397 sub reset_session_expires {
398 my ( $c, $sid ) = @_;
400 my $exp = $c->calculate_initial_session_expires;
401 $c->_session_expires( $exp );
403 # since we're setting _session_expires directly, make load_session_expires
404 # actually use that value.
406 $c->_tried_loading_session_expires(1);
407 $c->_extended_session_expires( $exp );
414 return $c->_sessionid || $c->_load_sessionid;
417 sub _load_sessionid {
419 return if $c->_tried_loading_session_id;
420 $c->_tried_loading_session_id(1);
422 if ( defined( my $sid = $c->get_session_id ) ) {
423 if ( $c->validate_session_id($sid) ) {
424 # temporarily set the inner key, so that validation will work
425 $c->_sessionid($sid);
428 my $err = "Tried to set invalid session ID '$sid'";
429 $c->log->error($err);
430 Catalyst::Exception->throw($err);
437 sub session_is_valid {
440 # force a check for expiry, but also __address, etc
441 if ( $c->_load_session ) {
448 sub validate_session_id {
449 my ( $c, $sid ) = @_;
451 $sid and $sid =~ /^[a-f\d]+$/i;
457 my $session = $c->_session || $c->_load_session || do {
458 $c->create_session_id_if_needed;
459 $c->initialize_session_data;
463 my $new_values = @_ > 1 ? { @_ } : $_[0];
464 croak('session takes a hash or hashref') unless ref $new_values;
466 for my $key (keys %$new_values) {
467 $session->{$key} = $new_values->{$key};
475 my ( $c, @keys ) = @_;
476 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
477 (@{$href}{@keys}) = ((undef) x @keys);
482 $c->_flash || $c->_load_flash || do {
483 $c->create_session_id_if_needed;
491 my $items = @_ > 1 ? {@_} : $_[0];
492 croak('flash takes a hash or hashref') unless ref $items;
493 @{ $c->_flash }{ keys %$items } = values %$items;
507 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
508 $c->_flash_key_hashes({});
509 $c->_flash_keep_keys({});
513 sub session_expire_key {
514 my ( $c, %keys ) = @_;
517 @{ $c->session->{__expire_keys} }{ keys %keys } =
518 map { $now + $_ } values %keys;
521 sub initialize_session_data {
532 $c->_session_plugin_config->{verify_address}
533 ? ( __address => $c->request->address||'' )
537 $c->_session_plugin_config->{verify_user_agent}
538 ? ( __user_agent => $c->request->user_agent||'' )
545 sub generate_session_id {
548 my $digest = $c->_find_digest();
549 $digest->add( $c->session_hash_seed() );
550 return $digest->hexdigest;
553 sub create_session_id_if_needed {
555 $c->create_session_id unless $c->sessionid;
558 sub create_session_id {
561 my $sid = $c->generate_session_id;
563 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
565 $c->_sessionid($sid);
566 $c->reset_session_expires;
567 $c->set_session_id($sid);
574 sub session_hash_seed {
577 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
582 sub _find_digest () {
584 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
585 if ( eval { Digest->new($alg) } ) {
590 Catalyst::Exception->throw(
591 "Could not find a suitable Digest module. Please install "
592 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
596 return Digest->new($usable);
603 $c->maybe::next::method(),
606 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
612 sub get_session_id { shift->maybe::next::method(@_) }
613 sub set_session_id { shift->maybe::next::method(@_) }
614 sub delete_session_id { shift->maybe::next::method(@_) }
615 sub extend_session_id { shift->maybe::next::method(@_) }
625 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
629 # To get sessions to "just work", all you need to do is use these plugins:
633 Session::Store::FastMmap
634 Session::State::Cookie
637 # you can replace Store::FastMmap with Store::File - both have sensible
638 # default configurations (see their docs for details)
640 # more complicated backends are available for other scenarios (DBI storage,
644 # after you've loaded the plugins you can save session data
645 # For example, if you are writing a shopping cart, it could be implemented
648 sub add_item : Local {
649 my ( $self, $c ) = @_;
651 my $item_id = $c->req->param("item");
653 # $c->session is a hash ref, a bit like $c->stash
654 # the difference is that it' preserved across requests
656 push @{ $c->session->{items} }, $item_id;
658 $c->forward("MyView");
661 sub display_items : Local {
662 my ( $self, $c ) = @_;
664 # values in $c->session are restored
665 $c->stash->{items_to_display} =
666 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
668 $c->forward("MyView");
673 The Session plugin is the base of two related parts of functionality required
674 for session management in web applications.
676 The first part, the State, is getting the browser to repeat back a session key,
677 so that the web application can identify the client and logically string
678 several requests together into a session.
680 The second part, the Store, deals with the actual storage of information about
681 the client. This data is stored so that the it may be revived for every request
682 made by the same client.
684 This plugin links the two pieces together.
686 =head1 RECOMENDED BACKENDS
690 =item Session::State::Cookie
692 The only really sane way to do state is using cookies.
694 =item Session::Store::File
696 A portable backend, based on Cache::File.
698 =item Session::Store::FastMmap
700 A fast and flexible backend, based on Cache::FastMmap.
710 An accessor for the session ID value.
714 Returns a hash reference that might contain unserialized values from previous
715 requests in the same session, and whose modified value will be saved for future
718 This method will automatically create a new session and session ID if none
721 You can also set session keys by passing a list of key/value pairs or a
724 $c->session->{foo} = "bar"; # This works.
725 $c->session(one => 1, two => 2); # And this.
726 $c->session({ answer => 42 }); # And this.
728 =item session_expires
730 This method returns the time when the current session will expire, or 0 if
731 there is no current session. If there is a session and it already expired, it
732 will delete the session and return 0 as well.
736 This is like Ruby on Rails' flash data structure. Think of it as a stash that
737 lasts for longer than one request, letting you redirect instead of forward.
739 The flash data will be cleaned up only on requests on which actually use
740 $c->flash (thus allowing multiple redirections), and the policy is to delete
741 all the keys which haven't changed since the flash data was loaded at the end
744 Note that use of the flash is an easy way to get data across requests, but
745 it's also strongly disrecommended, due it it being inherently plagued with
746 race conditions. This means that it's unlikely to work well if your
747 users have multiple tabs open at once, or if your site does a lot of AJAX
750 L<Catalyst::Plugin::StatusMessage> is the recommended alternative solution,
751 as this doesn't suffer from these issues.
754 my ( $self, $c ) = @_;
756 $c->flash->{beans} = 10;
757 $c->response->redirect( $c->uri_for("foo") );
761 my ( $self, $c ) = @_;
763 my $value = $c->flash->{beans};
767 $c->response->redirect( $c->uri_for("bar") );
771 my ( $self, $c ) = @_;
773 if ( exists $c->flash->{beans} ) { # false
780 Zap all the keys in the flash regardless of their current state.
782 =item keep_flash @keys
784 If you want to keep a flash key for the next request too, even if it hasn't
785 changed, call C<keep_flash> and pass in the keys as arguments.
787 =item delete_session REASON
789 This method is used to invalidate a session. It takes an optional parameter
790 which will be saved in C<session_delete_reason> if provided.
792 NOTE: This method will B<also> delete your flash data.
794 =item session_delete_reason
796 This accessor contains a string with the reason a session was deleted. Possible
811 =item session_expire_key $key, $ttl
813 Mark a key to expire at a certain time (only useful when shorter than the
814 expiry time for the whole session).
818 __PACKAGE__->config('Plugin::Session' => { expires => 10000000000 }); # "forever"
819 (NB If this number is too large, Y2K38 breakage could result.)
823 $c->session_expire_key( __user => 3600 );
825 Will make the session data survive, but the user will still be logged out after
828 Note that these values are not auto extended.
830 =item change_session_id
832 By calling this method you can force a session id change while keeping all
833 session data. This method might come handy when you are paranoid about some
834 advanced variations of session fixation attack.
836 If you want to prevent this session fixation scenario:
838 0) let us have WebApp with anonymous and authenticated parts
839 1) a hacker goes to vulnerable WebApp and gets a real sessionid,
840 just by browsing anonymous part of WebApp
841 2) the hacker inserts (somehow) this values into a cookie in victim's browser
842 3) after the victim logs into WebApp the hacker can enter his/her session
844 you should call change_session_id in your login controller like this:
846 if ($c->authenticate( { username => $user, password => $pass } )) {
848 $c->change_session_id;
855 =item change_session_expires $expires
857 You can change the session expiration time for this session;
859 $c->change_session_expires( 4000 );
861 Note that this only works to set the session longer than the config setting.
865 =head1 INTERNAL METHODS
871 This method is extended to also make calls to
872 C<check_session_plugin_requirements> and C<setup_session>.
874 =item check_session_plugin_requirements
876 This method ensures that a State and a Store plugin are also in use by the
881 This method populates C<< $c->config('Plugin::Session') >> with the default values
882 listed in L</CONFIGURATION>.
886 This method is extended.
888 Its only effect is if the (off by default) C<flash_to_stash> configuration
889 parameter is on - then it will copy the contents of the flash to the stash at
892 =item finalize_headers
894 This method is extended and will extend the expiry time before sending
899 This method is extended and will call finalize_session before the other
900 finalize_body methods run. Here we persist the session data if a session exists.
902 =item initialize_session_data
904 This method will initialize the internal structure of the session, and is
905 called by the C<session> method if appropriate.
907 =item create_session_id
909 Creates a new session ID using C<generate_session_id> if there is no session ID
912 =item validate_session_id SID
914 Make sure a session ID is of the right format.
916 This currently ensures that the session ID string is any amount of case
917 insensitive hexadecimal characters.
919 =item generate_session_id
921 This method will return a string that can be used as a session ID. It is
922 supposed to be a reasonably random string with enough bits to prevent
923 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
924 MD5 or SHA-256, depending on the availability of these modules.
926 =item session_hash_seed
928 This method is actually rather internal to generate_session_id, but should be
929 overridable in case you want to provide more random data.
931 Currently it returns a concatenated string which contains:
937 =item * The current time
939 =item * One value from C<rand>.
941 =item * The stringified value of a newly allocated hash reference
943 =item * The stringified value of the Catalyst context object
947 in the hopes that those combined values are entropic enough for most uses. If
948 this is not the case you can replace C<session_hash_seed> with e.g.
950 sub session_hash_seed {
951 open my $fh, "<", "/dev/random";
952 read $fh, my $bytes, 20;
957 Or even more directly, replace C<generate_session_id>:
959 sub generate_session_id {
960 open my $fh, "<", "/dev/random";
961 read $fh, my $bytes, 20;
963 return unpack("H*", $bytes);
966 Also have a look at L<Crypt::Random> and the various openssl bindings - these
967 modules provide APIs for cryptographically secure random data.
969 =item finalize_session
971 Clean up the session during C<finalize>.
973 This clears the various accessors after saving to the store.
977 See L<Catalyst/dump_these> - ammends the session data structure to the list of
978 dumped objects if session ID is defined.
981 =item calculate_extended_session_expires
983 =item calculate_initial_session_expires
985 =item create_session_id_if_needed
987 =item delete_session_id
989 =item extend_session_expires
991 Note: this is *not* used to give an individual user a longer session. See
992 'change_session_expires'.
994 =item extend_session_id
998 =item reset_session_expires
1000 =item session_is_valid
1002 =item set_session_id
1004 =item initial_session_expires
1008 =head1 USING SESSIONS DURING PREPARE
1010 The earliest point in time at which you may use the session data is after
1011 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
1013 State plugins must set $c->session ID before C<prepare_action>, and during
1014 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
1017 sub prepare_action {
1020 # don't touch $c->session yet!
1022 $c->NEXT::prepare_action( @_ );
1024 $c->session; # this is OK
1025 $c->sessionid; # this is also OK
1028 =head1 CONFIGURATION
1030 $c->config('Plugin::Session' => {
1034 All configuation parameters are provided in a hash reference under the
1035 C<Plugin::Session> key in the configuration hash.
1041 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
1044 =item verify_address
1046 When true, C<<$c->request->address>> will be checked at prepare time. If it is
1047 not the same as the address that initiated the session, the session is deleted.
1051 =item verify_user_agent
1053 When true, C<<$c->request->user_agent>> will be checked at prepare time. If it
1054 is not the same as the user agent that initiated the session, the session is
1059 =item flash_to_stash
1061 This option makes it easier to have actions behave the same whether they were
1062 forwarded to or redirected to. On prepare time it copies the contents of
1063 C<flash> (if any) to the stash.
1069 The hash reference returned by C<< $c->session >> contains several keys which
1070 are automatically set:
1076 This key no longer exists. Use C<session_expires> instead.
1080 The last time a session was saved to the store.
1084 The time when the session was first created.
1088 The value of C<< $c->request->address >> at the time the session was created.
1089 This value is only populated if C<verify_address> is true in the configuration.
1093 The value of C<< $c->request->user_agent >> at the time the session was created.
1094 This value is only populated if C<verify_user_agent> is true in the configuration.
1100 =head2 Round the Robin Proxies
1102 C<verify_address> could make your site inaccessible to users who are behind
1103 load balanced proxies. Some ISPs may give a different IP to each request by the
1104 same client due to this type of proxying. If addresses are verified these
1105 users' sessions cannot persist.
1107 To let these users access your site you can either disable address verification
1108 as a whole, or provide a checkbox in the login dialog that tells the server
1109 that it's OK for the address of the client to change. When the server sees that
1110 this box is checked it should delete the C<__address> special key from the
1111 session hash when the hash is first created.
1113 =head2 Race Conditions
1115 In this day and age where cleaning detergents and Dutch football (not the
1116 American kind) teams roam the plains in great numbers, requests may happen
1117 simultaneously. This means that there is some risk of session data being
1118 overwritten, like this:
1124 request a starts, request b starts, with the same session ID
1128 session data is loaded in request a
1132 session data is loaded in request b
1136 session data is changed in request a
1140 request a finishes, session data is updated and written to store
1144 request b finishes, session data is updated and written to store, overwriting
1145 changes by request a
1149 For applications where any given user's session is only making one request
1150 at a time this plugin should be safe enough.
1158 Yuval Kogman, C<nothingmuch@woobling.org>
1162 Tomas Doran (t0m) C<bobtfish@bobtfish.net> (current maintainer)
1168 Florian Ragwitz (rafl) C<rafl@debian.org>
1170 Kent Fredric (kentnl)
1172 And countless other contributers from #catalyst. Thanks guys!
1176 Devin Austin (dhoss) <dhoss@cpan.org>
1178 =head1 COPYRIGHT & LICENSE
1180 Copyright (c) 2005 the aforementioned authors. All rights
1181 reserved. This program is free software; you can redistribute
1182 it and/or modify it under the same terms as Perl itself.