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 = '0.29';
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 && $session_data->{__address} ne $c->request->address )
231 "Deleting session $sid due to address mismatch ("
232 . $session_data->{__address} . " != "
233 . $c->request->address . ")"
235 $c->delete_session("address mismatch");
238 if ( $c->_session_plugin_config->{verify_user_agent}
239 && $session_data->{__user_agent} ne $c->request->user_agent )
242 "Deleting session $sid due to user agent mismatch ("
243 . $session_data->{__user_agent} . " != "
244 . $c->request->user_agent . ")"
246 $c->delete_session("user agent mismatch");
250 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
251 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
252 $c->_expire_session_keys;
254 return $session_data;
263 return $c->_flash if $c->_tried_loading_flash_data;
264 $c->_tried_loading_flash_data(1);
266 if ( my $sid = $c->sessionid ) {
268 my $session_data = $c->session;
269 $c->_flash($session_data->{__flash});
271 if ( my $flash_data = $c->_flash )
273 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
282 sub _expire_session_keys {
283 my ( $c, $data ) = @_;
287 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
288 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
289 delete $c->_session->{$key};
290 delete $expire_times->{$key};
294 sub _clear_session_instance_data {
296 $c->$_(undef) for @session_data_accessors;
297 $c->maybe::next::method(@_); # allow other plugins to hook in on this
300 sub change_session_id {
303 my $sessiondata = $c->session;
304 my $oldsid = $c->sessionid;
305 my $newsid = $c->create_session_id;
308 $c->log->debug(qq/change_sessid: deleting session data from "$oldsid"/) if $c->debug;
309 $c->delete_session_data("${_}:${oldsid}") for qw/session expires flash/;
312 $c->log->debug(qq/change_sessid: storing session data to "$newsid"/) if $c->debug;
313 $c->store_session_data( "session:$newsid" => $sessiondata );
319 my ( $c, $msg ) = @_;
321 $c->log->debug("Deleting session" . ( defined($msg) ? "($msg)" : '(no reason given)') ) if $c->debug;
323 # delete the session data
324 if ( my $sid = $c->sessionid ) {
325 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
326 $c->delete_session_id($sid);
329 # reset the values in the context object
330 # see the BEGIN block
331 $c->_clear_session_instance_data;
333 $c->_session_delete_reason($msg);
336 sub session_delete_reason {
339 $c->session_is_valid; # check that it was loaded
341 $c->_session_delete_reason(@_);
344 sub session_expires {
347 if ( defined( my $expires = $c->_extended_session_expires ) ) {
349 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
350 return $c->extend_session_expires( $expires );
356 sub extend_session_expires {
357 my ( $c, $expires ) = @_;
358 $c->_extended_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
359 $c->extend_session_id( $c->sessionid, $updated );
363 sub calculate_initial_session_expires {
365 return ( time() + $c->_session_plugin_config->{expires} );
368 sub calculate_extended_session_expires {
369 my ( $c, $prev ) = @_;
370 $c->calculate_initial_session_expires;
373 sub reset_session_expires {
374 my ( $c, $sid ) = @_;
376 my $exp = $c->calculate_initial_session_expires;
377 $c->_session_expires( $exp );
379 # since we're setting _session_expires directly, make load_session_expires
380 # actually use that value.
382 $c->_tried_loading_session_expires(1);
383 $c->_extended_session_expires( $exp );
390 return $c->_sessionid || $c->_load_sessionid;
393 sub _load_sessionid {
395 return if $c->_tried_loading_session_id;
396 $c->_tried_loading_session_id(1);
398 if ( defined( my $sid = $c->get_session_id ) ) {
399 if ( $c->validate_session_id($sid) ) {
400 # temporarily set the inner key, so that validation will work
401 $c->_sessionid($sid);
404 my $err = "Tried to set invalid session ID '$sid'";
405 $c->log->error($err);
406 Catalyst::Exception->throw($err);
413 sub session_is_valid {
416 # force a check for expiry, but also __address, etc
417 if ( $c->_load_session ) {
424 sub validate_session_id {
425 my ( $c, $sid ) = @_;
427 $sid and $sid =~ /^[a-f\d]+$/i;
433 my $session = $c->_session || $c->_load_session || do {
434 $c->create_session_id_if_needed;
435 $c->initialize_session_data;
439 my $new_values = @_ > 1 ? { @_ } : $_[0];
440 croak('session takes a hash or hashref') unless ref $new_values;
442 for my $key (keys %$new_values) {
443 $session->{$key} = $new_values->{$key};
451 my ( $c, @keys ) = @_;
452 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
453 (@{$href}{@keys}) = ((undef) x @keys);
458 $c->_flash || $c->_load_flash || do {
459 $c->create_session_id_if_needed;
467 my $items = @_ > 1 ? {@_} : $_[0];
468 croak('flash takes a hash or hashref') unless ref $items;
469 @{ $c->_flash }{ keys %$items } = values %$items;
483 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
484 $c->_flash_key_hashes({});
485 $c->_flash_keep_keys({});
489 sub session_expire_key {
490 my ( $c, %keys ) = @_;
493 @{ $c->session->{__expire_keys} }{ keys %keys } =
494 map { $now + $_ } values %keys;
497 sub initialize_session_data {
508 $c->_session_plugin_config->{verify_address}
509 ? ( __address => $c->request->address||'' )
513 $c->_session_plugin_config->{verify_user_agent}
514 ? ( __user_agent => $c->request->user_agent||'' )
521 sub generate_session_id {
524 my $digest = $c->_find_digest();
525 $digest->add( $c->session_hash_seed() );
526 return $digest->hexdigest;
529 sub create_session_id_if_needed {
531 $c->create_session_id unless $c->sessionid;
534 sub create_session_id {
537 my $sid = $c->generate_session_id;
539 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
541 $c->_sessionid($sid);
542 $c->reset_session_expires;
543 $c->set_session_id($sid);
550 sub session_hash_seed {
553 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
558 sub _find_digest () {
560 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
561 if ( eval { Digest->new($alg) } ) {
566 Catalyst::Exception->throw(
567 "Could not find a suitable Digest module. Please install "
568 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
572 return Digest->new($usable);
579 $c->maybe::next::method(),
582 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
588 sub get_session_id { shift->maybe::next::method(@_) }
589 sub set_session_id { shift->maybe::next::method(@_) }
590 sub delete_session_id { shift->maybe::next::method(@_) }
591 sub extend_session_id { shift->maybe::next::method(@_) }
601 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
605 # To get sessions to "just work", all you need to do is use these plugins:
609 Session::Store::FastMmap
610 Session::State::Cookie
613 # you can replace Store::FastMmap with Store::File - both have sensible
614 # default configurations (see their docs for details)
616 # more complicated backends are available for other scenarios (DBI storage,
620 # after you've loaded the plugins you can save session data
621 # For example, if you are writing a shopping cart, it could be implemented
624 sub add_item : Local {
625 my ( $self, $c ) = @_;
627 my $item_id = $c->req->param("item");
629 # $c->session is a hash ref, a bit like $c->stash
630 # the difference is that it' preserved across requests
632 push @{ $c->session->{items} }, $item_id;
634 $c->forward("MyView");
637 sub display_items : Local {
638 my ( $self, $c ) = @_;
640 # values in $c->session are restored
641 $c->stash->{items_to_display} =
642 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
644 $c->forward("MyView");
649 The Session plugin is the base of two related parts of functionality required
650 for session management in web applications.
652 The first part, the State, is getting the browser to repeat back a session key,
653 so that the web application can identify the client and logically string
654 several requests together into a session.
656 The second part, the Store, deals with the actual storage of information about
657 the client. This data is stored so that the it may be revived for every request
658 made by the same client.
660 This plugin links the two pieces together.
662 =head1 RECOMENDED BACKENDS
666 =item Session::State::Cookie
668 The only really sane way to do state is using cookies.
670 =item Session::Store::File
672 A portable backend, based on Cache::File.
674 =item Session::Store::FastMmap
676 A fast and flexible backend, based on Cache::FastMmap.
686 An accessor for the session ID value.
690 Returns a hash reference that might contain unserialized values from previous
691 requests in the same session, and whose modified value will be saved for future
694 This method will automatically create a new session and session ID if none
697 You can also set session keys by passing a list of key/value pairs or a
700 $c->session->{foo} = "bar"; # This works.
701 $c->session(one => 1, two => 2); # And this.
702 $c->session({ answer => 42 }); # And this.
704 =item session_expires
706 =item session_expires $reset
708 This method returns the time when the current session will expire, or 0 if
709 there is no current session. If there is a session and it already expired, it
710 will delete the session and return 0 as well.
712 If the C<$reset> parameter is true, and there is a session ID the expiry time
713 will be reset to the current time plus the time to live (see
714 L</CONFIGURATION>). This is used when creating a new session.
718 This is like Ruby on Rails' flash data structure. Think of it as a stash that
719 lasts for longer than one request, letting you redirect instead of forward.
721 The flash data will be cleaned up only on requests on which actually use
722 $c->flash (thus allowing multiple redirections), and the policy is to delete
723 all the keys which haven't changed since the flash data was loaded at the end
727 my ( $self, $c ) = @_;
729 $c->flash->{beans} = 10;
730 $c->response->redirect( $c->uri_for("foo") );
734 my ( $self, $c ) = @_;
736 my $value = $c->flash->{beans};
740 $c->response->redirect( $c->uri_for("bar") );
744 my ( $self, $c ) = @_;
746 if ( exists $c->flash->{beans} ) { # false
753 Zap all the keys in the flash regardless of their current state.
755 =item keep_flash @keys
757 If you want to keep a flash key for the next request too, even if it hasn't
758 changed, call C<keep_flash> and pass in the keys as arguments.
760 =item delete_session REASON
762 This method is used to invalidate a session. It takes an optional parameter
763 which will be saved in C<session_delete_reason> if provided.
765 NOTE: This method will B<also> delete your flash data.
767 =item session_delete_reason
769 This accessor contains a string with the reason a session was deleted. Possible
784 =item session_expire_key $key, $ttl
786 Mark a key to expire at a certain time (only useful when shorter than the
787 expiry time for the whole session).
791 __PACKAGE__->config('Plugin::Session' => { expires => 1000000000000 }); # forever
795 $c->session_expire_key( __user => 3600 );
797 Will make the session data survive, but the user will still be logged out after
800 Note that these values are not auto extended.
802 =item change_session_id
804 By calling this method you can force a session id change while keeping all
805 session data. This method might come handy when you are paranoid about some
806 advanced variations of session fixation attack.
808 If you want to prevent this session fixation scenario:
810 0) let us have WebApp with anonymous and authenticated parts
811 1) a hacker goes to vulnerable WebApp and gets a real sessionid,
812 just by browsing anonymous part of WebApp
813 2) the hacker inserts (somehow) this values into a cookie in victim's browser
814 3) after the victim logs into WebApp the hacker can enter his/her session
816 you should call change_session_id in your login controller like this:
818 if ($c->authenticate( { username => $user, password => $pass } )) {
820 $c->change_session_id;
829 =head1 INTERNAL METHODS
835 This method is extended to also make calls to
836 C<check_session_plugin_requirements> and C<setup_session>.
838 =item check_session_plugin_requirements
840 This method ensures that a State and a Store plugin are also in use by the
845 This method populates C<< $c->config('Plugin::Session') >> with the default values
846 listed in L</CONFIGURATION>.
850 This method is extended.
852 Its only effect is if the (off by default) C<flash_to_stash> configuration
853 parameter is on - then it will copy the contents of the flash to the stash at
856 =item finalize_headers
858 This method is extended and will extend the expiry time before sending
863 This method is extended and will call finalize_session before the other
864 finalize_body methods run. Here we persist the session data if a session exists.
866 =item initialize_session_data
868 This method will initialize the internal structure of the session, and is
869 called by the C<session> method if appropriate.
871 =item create_session_id
873 Creates a new session ID using C<generate_session_id> if there is no session ID
876 =item validate_session_id SID
878 Make sure a session ID is of the right format.
880 This currently ensures that the session ID string is any amount of case
881 insensitive hexadecimal characters.
883 =item generate_session_id
885 This method will return a string that can be used as a session ID. It is
886 supposed to be a reasonably random string with enough bits to prevent
887 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
888 MD5 or SHA-256, depending on the availability of these modules.
890 =item session_hash_seed
892 This method is actually rather internal to generate_session_id, but should be
893 overridable in case you want to provide more random data.
895 Currently it returns a concatenated string which contains:
901 =item * The current time
903 =item * One value from C<rand>.
905 =item * The stringified value of a newly allocated hash reference
907 =item * The stringified value of the Catalyst context object
911 in the hopes that those combined values are entropic enough for most uses. If
912 this is not the case you can replace C<session_hash_seed> with e.g.
914 sub session_hash_seed {
915 open my $fh, "<", "/dev/random";
916 read $fh, my $bytes, 20;
921 Or even more directly, replace C<generate_session_id>:
923 sub generate_session_id {
924 open my $fh, "<", "/dev/random";
925 read $fh, my $bytes, 20;
927 return unpack("H*", $bytes);
930 Also have a look at L<Crypt::Random> and the various openssl bindings - these
931 modules provide APIs for cryptographically secure random data.
933 =item finalize_session
935 Clean up the session during C<finalize>.
937 This clears the various accessors after saving to the store.
941 See L<Catalyst/dump_these> - ammends the session data structure to the list of
942 dumped objects if session ID is defined.
945 =item calculate_extended_session_expires
947 =item calculate_initial_session_expires
949 =item create_session_id_if_needed
951 =item delete_session_id
953 =item extend_session_expires
955 =item extend_session_id
959 =item reset_session_expires
961 =item session_is_valid
967 =head1 USING SESSIONS DURING PREPARE
969 The earliest point in time at which you may use the session data is after
970 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
972 State plugins must set $c->session ID before C<prepare_action>, and during
973 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
979 # don't touch $c->session yet!
981 $c->NEXT::prepare_action( @_ );
983 $c->session; # this is OK
984 $c->sessionid; # this is also OK
989 $c->config('Plugin::Session' => {
993 All configuation parameters are provided in a hash reference under the
994 C<Plugin::Session> key in the configuration hash.
1000 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
1003 =item verify_address
1005 When true, C<<$c->request->address>> will be checked at prepare time. If it is
1006 not the same as the address that initiated the session, the session is deleted.
1010 =item verify_user_agent
1012 When true, C<<$c->request->user_agent>> will be checked at prepare time. If it
1013 is not the same as the user agent that initiated the session, the session is
1018 =item flash_to_stash
1020 This option makes it easier to have actions behave the same whether they were
1021 forwarded to or redirected to. On prepare time it copies the contents of
1022 C<flash> (if any) to the stash.
1028 The hash reference returned by C<< $c->session >> contains several keys which
1029 are automatically set:
1035 This key no longer exists. Use C<session_expires> instead.
1039 The last time a session was saved to the store.
1043 The time when the session was first created.
1047 The value of C<< $c->request->address >> at the time the session was created.
1048 This value is only populated if C<verify_address> is true in the configuration.
1052 The value of C<< $c->request->user_agent >> at the time the session was created.
1053 This value is only populated if C<verify_user_agent> is true in the configuration.
1059 =head2 Round the Robin Proxies
1061 C<verify_address> could make your site inaccessible to users who are behind
1062 load balanced proxies. Some ISPs may give a different IP to each request by the
1063 same client due to this type of proxying. If addresses are verified these
1064 users' sessions cannot persist.
1066 To let these users access your site you can either disable address verification
1067 as a whole, or provide a checkbox in the login dialog that tells the server
1068 that it's OK for the address of the client to change. When the server sees that
1069 this box is checked it should delete the C<__address> special key from the
1070 session hash when the hash is first created.
1072 =head2 Race Conditions
1074 In this day and age where cleaning detergents and Dutch football (not the
1075 American kind) teams roam the plains in great numbers, requests may happen
1076 simultaneously. This means that there is some risk of session data being
1077 overwritten, like this:
1083 request a starts, request b starts, with the same session ID
1087 session data is loaded in request a
1091 session data is loaded in request b
1095 session data is changed in request a
1099 request a finishes, session data is updated and written to store
1103 request b finishes, session data is updated and written to store, overwriting
1104 changes by request a
1108 If this is a concern in your application, a soon-to-be-developed locking
1109 solution is the only safe way to go. This will have a bigger overhead.
1111 For applications where any given user is only making one request at a time this
1112 plugin should be safe enough.
1120 Yuval Kogman, C<nothingmuch@woobling.org>
1124 Tomas Doran (t0m) C<bobtfish@bobtfish.net> (current maintainer)
1130 Florian Ragwitz (rafl) C<rafl@debian.org>
1132 Kent Fredric (kentnl)
1134 And countless other contributers from #catalyst. Thanks guys!
1136 =head1 COPYRIGHT & LICENSE
1138 Copyright (c) 2005 the aforementioned authors. All rights
1139 reserved. This program is free software; you can redistribute
1140 it and/or modify it under the same terms as Perl itself.