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 = '0.32';
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 # fix cookie before we send headers
106 $c->_save_session_expires;
108 return $c->maybe::next::method(@_);
114 # We have to finalize our session *before* $c->engine->finalize_xxx is called,
115 # because we do not want to send the HTTP response before the session is stored/committed to
116 # the session database (or whatever Session::Store you use).
117 $c->finalize_session;
119 return $c->maybe::next::method(@_);
122 sub finalize_session {
125 $c->maybe::next::method(@_);
127 $c->_save_session_id;
131 $c->_clear_session_instance_data;
134 sub _save_session_id {
137 # we already called set when allocating
138 # no need to tell the state plugins anything new
141 sub _save_session_expires {
144 if ( defined($c->_session_expires) ) {
145 my $expires = $c->session_expires; # force extension
147 my $sid = $c->sessionid;
148 $c->store_session_data( "expires:$sid" => $expires );
155 if ( my $session_data = $c->_session ) {
157 no warnings 'uninitialized';
158 if ( Object::Signature::signature($session_data) ne
159 $c->_session_data_sig )
161 $session_data->{__updated} = time();
162 my $sid = $c->sessionid;
163 $c->store_session_data( "session:$sid" => $session_data );
171 if ( my $flash_data = $c->_flash ) {
173 my $hashes = $c->_flash_key_hashes || {};
174 my $keep = $c->_flash_keep_keys || {};
175 foreach my $key ( keys %$hashes ) {
176 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
177 delete $flash_data->{$key};
181 my $sid = $c->sessionid;
183 my $session_data = $c->_session;
185 $session_data->{__flash} = $flash_data;
188 delete $session_data->{__flash};
190 $c->_session($session_data);
195 sub _load_session_expires {
197 return $c->_session_expires if $c->_tried_loading_session_expires;
198 $c->_tried_loading_session_expires(1);
200 if ( my $sid = $c->sessionid ) {
201 my $expires = $c->get_session_data("expires:$sid") || 0;
203 if ( $expires >= time() ) {
204 $c->_session_expires( $expires );
207 $c->delete_session( "session expired" );
217 return $c->_session if $c->_tried_loading_session_data;
218 $c->_tried_loading_session_data(1);
220 if ( my $sid = $c->sessionid ) {
221 if ( $c->_load_session_expires ) { # > 0
223 my $session_data = $c->get_session_data("session:$sid") || return;
224 $c->_session($session_data);
226 no warnings 'uninitialized'; # ne __address
227 if ( $c->_session_plugin_config->{verify_address}
228 && exists $session_data->{__address}
229 && $session_data->{__address} ne $c->request->address )
232 "Deleting session $sid due to address mismatch ("
233 . $session_data->{__address} . " != "
234 . $c->request->address . ")"
236 $c->delete_session("address mismatch");
239 if ( $c->_session_plugin_config->{verify_user_agent}
240 && $session_data->{__user_agent} ne $c->request->user_agent )
243 "Deleting session $sid due to user agent mismatch ("
244 . $session_data->{__user_agent} . " != "
245 . $c->request->user_agent . ")"
247 $c->delete_session("user agent mismatch");
251 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
252 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
253 $c->_expire_session_keys;
255 return $session_data;
264 return $c->_flash if $c->_tried_loading_flash_data;
265 $c->_tried_loading_flash_data(1);
267 if ( my $sid = $c->sessionid ) {
269 my $session_data = $c->session;
270 $c->_flash($session_data->{__flash});
272 if ( my $flash_data = $c->_flash )
274 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
283 sub _expire_session_keys {
284 my ( $c, $data ) = @_;
288 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
289 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
290 delete $c->_session->{$key};
291 delete $expire_times->{$key};
295 sub _clear_session_instance_data {
297 $c->$_(undef) for @session_data_accessors;
298 $c->maybe::next::method(@_); # allow other plugins to hook in on this
301 sub change_session_id {
304 my $sessiondata = $c->session;
305 my $oldsid = $c->sessionid;
306 my $newsid = $c->create_session_id;
309 $c->log->debug(qq/change_sessid: deleting session data from "$oldsid"/) if $c->debug;
310 $c->delete_session_data("${_}:${oldsid}") for qw/session expires flash/;
313 $c->log->debug(qq/change_sessid: storing session data to "$newsid"/) if $c->debug;
314 $c->store_session_data( "session:$newsid" => $sessiondata );
320 my ( $c, $msg ) = @_;
322 $c->log->debug("Deleting session" . ( defined($msg) ? "($msg)" : '(no reason given)') ) if $c->debug;
324 # delete the session data
325 if ( my $sid = $c->sessionid ) {
326 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
327 $c->delete_session_id($sid);
330 # reset the values in the context object
331 # see the BEGIN block
332 $c->_clear_session_instance_data;
334 $c->_session_delete_reason($msg);
337 sub session_delete_reason {
340 $c->session_is_valid; # check that it was loaded
342 $c->_session_delete_reason(@_);
345 sub session_expires {
348 if ( defined( my $expires = $c->_extended_session_expires ) ) {
350 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
351 return $c->calculate_initial_session_expires;
357 sub extend_session_expires {
358 my ( $c, $expires ) = @_;
359 $c->_extended_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
360 $c->extend_session_id( $c->sessionid, $updated );
364 sub calculate_initial_session_expires {
366 return ( time() + $c->_session_plugin_config->{expires} );
369 sub calculate_extended_session_expires {
370 my ( $c, $prev ) = @_;
371 return ( time() + $prev );
374 sub reset_session_expires {
375 my ( $c, $sid ) = @_;
377 my $exp = $c->calculate_initial_session_expires;
378 $c->_session_expires( $exp );
380 # since we're setting _session_expires directly, make load_session_expires
381 # actually use that value.
383 $c->_tried_loading_session_expires(1);
384 $c->_extended_session_expires( $exp );
391 return $c->_sessionid || $c->_load_sessionid;
394 sub _load_sessionid {
396 return if $c->_tried_loading_session_id;
397 $c->_tried_loading_session_id(1);
399 if ( defined( my $sid = $c->get_session_id ) ) {
400 if ( $c->validate_session_id($sid) ) {
401 # temporarily set the inner key, so that validation will work
402 $c->_sessionid($sid);
405 my $err = "Tried to set invalid session ID '$sid'";
406 $c->log->error($err);
407 Catalyst::Exception->throw($err);
414 sub session_is_valid {
417 # force a check for expiry, but also __address, etc
418 if ( $c->_load_session ) {
425 sub validate_session_id {
426 my ( $c, $sid ) = @_;
428 $sid and $sid =~ /^[a-f\d]+$/i;
434 my $session = $c->_session || $c->_load_session || do {
435 $c->create_session_id_if_needed;
436 $c->initialize_session_data;
440 my $new_values = @_ > 1 ? { @_ } : $_[0];
441 croak('session takes a hash or hashref') unless ref $new_values;
443 for my $key (keys %$new_values) {
444 $session->{$key} = $new_values->{$key};
452 my ( $c, @keys ) = @_;
453 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
454 (@{$href}{@keys}) = ((undef) x @keys);
459 $c->_flash || $c->_load_flash || do {
460 $c->create_session_id_if_needed;
468 my $items = @_ > 1 ? {@_} : $_[0];
469 croak('flash takes a hash or hashref') unless ref $items;
470 @{ $c->_flash }{ keys %$items } = values %$items;
484 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
485 $c->_flash_key_hashes({});
486 $c->_flash_keep_keys({});
490 sub session_expire_key {
491 my ( $c, %keys ) = @_;
494 @{ $c->session->{__expire_keys} }{ keys %keys } =
495 map { $now + $_ } values %keys;
498 sub initialize_session_data {
509 $c->_session_plugin_config->{verify_address}
510 ? ( __address => $c->request->address||'' )
514 $c->_session_plugin_config->{verify_user_agent}
515 ? ( __user_agent => $c->request->user_agent||'' )
522 sub generate_session_id {
525 my $digest = $c->_find_digest();
526 $digest->add( $c->session_hash_seed() );
527 return $digest->hexdigest;
530 sub create_session_id_if_needed {
532 $c->create_session_id unless $c->sessionid;
535 sub create_session_id {
538 my $sid = $c->generate_session_id;
540 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
542 $c->_sessionid($sid);
543 $c->reset_session_expires;
544 $c->set_session_id($sid);
551 sub session_hash_seed {
554 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
559 sub _find_digest () {
561 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
562 if ( eval { Digest->new($alg) } ) {
567 Catalyst::Exception->throw(
568 "Could not find a suitable Digest module. Please install "
569 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
573 return Digest->new($usable);
580 $c->maybe::next::method(),
583 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
589 sub get_session_id { shift->maybe::next::method(@_) }
590 sub set_session_id { shift->maybe::next::method(@_) }
591 sub delete_session_id { shift->maybe::next::method(@_) }
592 sub extend_session_id { shift->maybe::next::method(@_) }
602 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
606 # To get sessions to "just work", all you need to do is use these plugins:
610 Session::Store::FastMmap
611 Session::State::Cookie
614 # you can replace Store::FastMmap with Store::File - both have sensible
615 # default configurations (see their docs for details)
617 # more complicated backends are available for other scenarios (DBI storage,
621 # after you've loaded the plugins you can save session data
622 # For example, if you are writing a shopping cart, it could be implemented
625 sub add_item : Local {
626 my ( $self, $c ) = @_;
628 my $item_id = $c->req->param("item");
630 # $c->session is a hash ref, a bit like $c->stash
631 # the difference is that it' preserved across requests
633 push @{ $c->session->{items} }, $item_id;
635 $c->forward("MyView");
638 sub display_items : Local {
639 my ( $self, $c ) = @_;
641 # values in $c->session are restored
642 $c->stash->{items_to_display} =
643 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
645 $c->forward("MyView");
650 The Session plugin is the base of two related parts of functionality required
651 for session management in web applications.
653 The first part, the State, is getting the browser to repeat back a session key,
654 so that the web application can identify the client and logically string
655 several requests together into a session.
657 The second part, the Store, deals with the actual storage of information about
658 the client. This data is stored so that the it may be revived for every request
659 made by the same client.
661 This plugin links the two pieces together.
663 =head1 RECOMENDED BACKENDS
667 =item Session::State::Cookie
669 The only really sane way to do state is using cookies.
671 =item Session::Store::File
673 A portable backend, based on Cache::File.
675 =item Session::Store::FastMmap
677 A fast and flexible backend, based on Cache::FastMmap.
687 An accessor for the session ID value.
691 Returns a hash reference that might contain unserialized values from previous
692 requests in the same session, and whose modified value will be saved for future
695 This method will automatically create a new session and session ID if none
698 You can also set session keys by passing a list of key/value pairs or a
701 $c->session->{foo} = "bar"; # This works.
702 $c->session(one => 1, two => 2); # And this.
703 $c->session({ answer => 42 }); # And this.
705 =item session_expires
707 =item session_expires $reset
709 This method returns the time when the current session will expire, or 0 if
710 there is no current session. If there is a session and it already expired, it
711 will delete the session and return 0 as well.
713 If the C<$reset> parameter is true, and there is a session ID the expiry time
714 will be reset to the current time plus the time to live (see
715 L</CONFIGURATION>). This is used when creating a new session.
719 This is like Ruby on Rails' flash data structure. Think of it as a stash that
720 lasts for longer than one request, letting you redirect instead of forward.
722 The flash data will be cleaned up only on requests on which actually use
723 $c->flash (thus allowing multiple redirections), and the policy is to delete
724 all the keys which haven't changed since the flash data was loaded at the end
728 my ( $self, $c ) = @_;
730 $c->flash->{beans} = 10;
731 $c->response->redirect( $c->uri_for("foo") );
735 my ( $self, $c ) = @_;
737 my $value = $c->flash->{beans};
741 $c->response->redirect( $c->uri_for("bar") );
745 my ( $self, $c ) = @_;
747 if ( exists $c->flash->{beans} ) { # false
754 Zap all the keys in the flash regardless of their current state.
756 =item keep_flash @keys
758 If you want to keep a flash key for the next request too, even if it hasn't
759 changed, call C<keep_flash> and pass in the keys as arguments.
761 =item delete_session REASON
763 This method is used to invalidate a session. It takes an optional parameter
764 which will be saved in C<session_delete_reason> if provided.
766 NOTE: This method will B<also> delete your flash data.
768 =item session_delete_reason
770 This accessor contains a string with the reason a session was deleted. Possible
785 =item session_expire_key $key, $ttl
787 Mark a key to expire at a certain time (only useful when shorter than the
788 expiry time for the whole session).
792 __PACKAGE__->config('Plugin::Session' => { expires => 10000000000 }); # "forever"
793 (NB If this number is too large, Y2K38 breakage could result.)
797 $c->session_expire_key( __user => 3600 );
799 Will make the session data survive, but the user will still be logged out after
802 Note that these values are not auto extended.
804 =item change_session_id
806 By calling this method you can force a session id change while keeping all
807 session data. This method might come handy when you are paranoid about some
808 advanced variations of session fixation attack.
810 If you want to prevent this session fixation scenario:
812 0) let us have WebApp with anonymous and authenticated parts
813 1) a hacker goes to vulnerable WebApp and gets a real sessionid,
814 just by browsing anonymous part of WebApp
815 2) the hacker inserts (somehow) this values into a cookie in victim's browser
816 3) after the victim logs into WebApp the hacker can enter his/her session
818 you should call change_session_id in your login controller like this:
820 if ($c->authenticate( { username => $user, password => $pass } )) {
822 $c->change_session_id;
831 =head1 INTERNAL METHODS
837 This method is extended to also make calls to
838 C<check_session_plugin_requirements> and C<setup_session>.
840 =item check_session_plugin_requirements
842 This method ensures that a State and a Store plugin are also in use by the
847 This method populates C<< $c->config('Plugin::Session') >> with the default values
848 listed in L</CONFIGURATION>.
852 This method is extended.
854 Its only effect is if the (off by default) C<flash_to_stash> configuration
855 parameter is on - then it will copy the contents of the flash to the stash at
858 =item finalize_headers
860 This method is extended and will extend the expiry time before sending
865 This method is extended and will call finalize_session before the other
866 finalize_body methods run. Here we persist the session data if a session exists.
868 =item initialize_session_data
870 This method will initialize the internal structure of the session, and is
871 called by the C<session> method if appropriate.
873 =item create_session_id
875 Creates a new session ID using C<generate_session_id> if there is no session ID
878 =item validate_session_id SID
880 Make sure a session ID is of the right format.
882 This currently ensures that the session ID string is any amount of case
883 insensitive hexadecimal characters.
885 =item generate_session_id
887 This method will return a string that can be used as a session ID. It is
888 supposed to be a reasonably random string with enough bits to prevent
889 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
890 MD5 or SHA-256, depending on the availability of these modules.
892 =item session_hash_seed
894 This method is actually rather internal to generate_session_id, but should be
895 overridable in case you want to provide more random data.
897 Currently it returns a concatenated string which contains:
903 =item * The current time
905 =item * One value from C<rand>.
907 =item * The stringified value of a newly allocated hash reference
909 =item * The stringified value of the Catalyst context object
913 in the hopes that those combined values are entropic enough for most uses. If
914 this is not the case you can replace C<session_hash_seed> with e.g.
916 sub session_hash_seed {
917 open my $fh, "<", "/dev/random";
918 read $fh, my $bytes, 20;
923 Or even more directly, replace C<generate_session_id>:
925 sub generate_session_id {
926 open my $fh, "<", "/dev/random";
927 read $fh, my $bytes, 20;
929 return unpack("H*", $bytes);
932 Also have a look at L<Crypt::Random> and the various openssl bindings - these
933 modules provide APIs for cryptographically secure random data.
935 =item finalize_session
937 Clean up the session during C<finalize>.
939 This clears the various accessors after saving to the store.
943 See L<Catalyst/dump_these> - ammends the session data structure to the list of
944 dumped objects if session ID is defined.
947 =item calculate_extended_session_expires
949 =item calculate_initial_session_expires
951 =item create_session_id_if_needed
953 =item delete_session_id
955 =item extend_session_expires
957 =item extend_session_id
961 =item reset_session_expires
963 =item session_is_valid
969 =head1 USING SESSIONS DURING PREPARE
971 The earliest point in time at which you may use the session data is after
972 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
974 State plugins must set $c->session ID before C<prepare_action>, and during
975 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
981 # don't touch $c->session yet!
983 $c->NEXT::prepare_action( @_ );
985 $c->session; # this is OK
986 $c->sessionid; # this is also OK
991 $c->config('Plugin::Session' => {
995 All configuation parameters are provided in a hash reference under the
996 C<Plugin::Session> key in the configuration hash.
1002 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
1005 =item verify_address
1007 When true, C<<$c->request->address>> will be checked at prepare time. If it is
1008 not the same as the address that initiated the session, the session is deleted.
1012 =item verify_user_agent
1014 When true, C<<$c->request->user_agent>> will be checked at prepare time. If it
1015 is not the same as the user agent that initiated the session, the session is
1020 =item flash_to_stash
1022 This option makes it easier to have actions behave the same whether they were
1023 forwarded to or redirected to. On prepare time it copies the contents of
1024 C<flash> (if any) to the stash.
1030 The hash reference returned by C<< $c->session >> contains several keys which
1031 are automatically set:
1037 This key no longer exists. Use C<session_expires> instead.
1041 The last time a session was saved to the store.
1045 The time when the session was first created.
1049 The value of C<< $c->request->address >> at the time the session was created.
1050 This value is only populated if C<verify_address> is true in the configuration.
1054 The value of C<< $c->request->user_agent >> at the time the session was created.
1055 This value is only populated if C<verify_user_agent> is true in the configuration.
1061 =head2 Round the Robin Proxies
1063 C<verify_address> could make your site inaccessible to users who are behind
1064 load balanced proxies. Some ISPs may give a different IP to each request by the
1065 same client due to this type of proxying. If addresses are verified these
1066 users' sessions cannot persist.
1068 To let these users access your site you can either disable address verification
1069 as a whole, or provide a checkbox in the login dialog that tells the server
1070 that it's OK for the address of the client to change. When the server sees that
1071 this box is checked it should delete the C<__address> special key from the
1072 session hash when the hash is first created.
1074 =head2 Race Conditions
1076 In this day and age where cleaning detergents and Dutch football (not the
1077 American kind) teams roam the plains in great numbers, requests may happen
1078 simultaneously. This means that there is some risk of session data being
1079 overwritten, like this:
1085 request a starts, request b starts, with the same session ID
1089 session data is loaded in request a
1093 session data is loaded in request b
1097 session data is changed in request a
1101 request a finishes, session data is updated and written to store
1105 request b finishes, session data is updated and written to store, overwriting
1106 changes by request a
1110 For applications where any given user's session is only making one request
1111 at a time this plugin should be safe enough.
1119 Yuval Kogman, C<nothingmuch@woobling.org>
1123 Tomas Doran (t0m) C<bobtfish@bobtfish.net> (current maintainer)
1129 Florian Ragwitz (rafl) C<rafl@debian.org>
1131 Kent Fredric (kentnl)
1133 And countless other contributers from #catalyst. Thanks guys!
1135 =head1 COPYRIGHT & LICENSE
1137 Copyright (c) 2005 the aforementioned authors. All rights
1138 reserved. This program is free software; you can redistribute
1139 it and/or modify it under the same terms as Perl itself.