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 = '0.28';
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 );
378 $c->_extended_session_expires( $exp );
385 return $c->_sessionid || $c->_load_sessionid;
388 sub _load_sessionid {
390 return if $c->_tried_loading_session_id;
391 $c->_tried_loading_session_id(1);
393 if ( defined( my $sid = $c->get_session_id ) ) {
394 if ( $c->validate_session_id($sid) ) {
395 # temporarily set the inner key, so that validation will work
396 $c->_sessionid($sid);
399 my $err = "Tried to set invalid session ID '$sid'";
400 $c->log->error($err);
401 Catalyst::Exception->throw($err);
408 sub session_is_valid {
411 # force a check for expiry, but also __address, etc
412 if ( $c->_load_session ) {
419 sub validate_session_id {
420 my ( $c, $sid ) = @_;
422 $sid and $sid =~ /^[a-f\d]+$/i;
428 my $session = $c->_session || $c->_load_session || do {
429 $c->create_session_id_if_needed;
430 $c->initialize_session_data;
434 my $new_values = @_ > 1 ? { @_ } : $_[0];
435 croak('session takes a hash or hashref') unless ref $new_values;
437 for my $key (keys %$new_values) {
438 $session->{$key} = $new_values->{$key};
446 my ( $c, @keys ) = @_;
447 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
448 (@{$href}{@keys}) = ((undef) x @keys);
453 $c->_flash || $c->_load_flash || do {
454 $c->create_session_id_if_needed;
462 my $items = @_ > 1 ? {@_} : $_[0];
463 croak('flash takes a hash or hashref') unless ref $items;
464 @{ $c->_flash }{ keys %$items } = values %$items;
478 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
479 $c->_flash_key_hashes({});
480 $c->_flash_keep_keys({});
484 sub session_expire_key {
485 my ( $c, %keys ) = @_;
488 @{ $c->session->{__expire_keys} }{ keys %keys } =
489 map { $now + $_ } values %keys;
492 sub initialize_session_data {
503 $c->_session_plugin_config->{verify_address}
504 ? ( __address => $c->request->address||'' )
508 $c->_session_plugin_config->{verify_user_agent}
509 ? ( __user_agent => $c->request->user_agent||'' )
516 sub generate_session_id {
519 my $digest = $c->_find_digest();
520 $digest->add( $c->session_hash_seed() );
521 return $digest->hexdigest;
524 sub create_session_id_if_needed {
526 $c->create_session_id unless $c->sessionid;
529 sub create_session_id {
532 my $sid = $c->generate_session_id;
534 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
536 $c->_sessionid($sid);
537 $c->reset_session_expires;
538 $c->set_session_id($sid);
545 sub session_hash_seed {
548 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
553 sub _find_digest () {
555 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
556 if ( eval { Digest->new($alg) } ) {
561 Catalyst::Exception->throw(
562 "Could not find a suitable Digest module. Please install "
563 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
567 return Digest->new($usable);
574 $c->maybe::next::method(),
577 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
583 sub get_session_id { shift->maybe::next::method(@_) }
584 sub set_session_id { shift->maybe::next::method(@_) }
585 sub delete_session_id { shift->maybe::next::method(@_) }
586 sub extend_session_id { shift->maybe::next::method(@_) }
596 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
600 # To get sessions to "just work", all you need to do is use these plugins:
604 Session::Store::FastMmap
605 Session::State::Cookie
608 # you can replace Store::FastMmap with Store::File - both have sensible
609 # default configurations (see their docs for details)
611 # more complicated backends are available for other scenarios (DBI storage,
615 # after you've loaded the plugins you can save session data
616 # For example, if you are writing a shopping cart, it could be implemented
619 sub add_item : Local {
620 my ( $self, $c ) = @_;
622 my $item_id = $c->req->param("item");
624 # $c->session is a hash ref, a bit like $c->stash
625 # the difference is that it' preserved across requests
627 push @{ $c->session->{items} }, $item_id;
629 $c->forward("MyView");
632 sub display_items : Local {
633 my ( $self, $c ) = @_;
635 # values in $c->session are restored
636 $c->stash->{items_to_display} =
637 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
639 $c->forward("MyView");
644 The Session plugin is the base of two related parts of functionality required
645 for session management in web applications.
647 The first part, the State, is getting the browser to repeat back a session key,
648 so that the web application can identify the client and logically string
649 several requests together into a session.
651 The second part, the Store, deals with the actual storage of information about
652 the client. This data is stored so that the it may be revived for every request
653 made by the same client.
655 This plugin links the two pieces together.
657 =head1 RECOMENDED BACKENDS
661 =item Session::State::Cookie
663 The only really sane way to do state is using cookies.
665 =item Session::Store::File
667 A portable backend, based on Cache::File.
669 =item Session::Store::FastMmap
671 A fast and flexible backend, based on Cache::FastMmap.
681 An accessor for the session ID value.
685 Returns a hash reference that might contain unserialized values from previous
686 requests in the same session, and whose modified value will be saved for future
689 This method will automatically create a new session and session ID if none
692 You can also set session keys by passing a list of key/value pairs or a
695 $c->session->{foo} = "bar"; # This works.
696 $c->session(one => 1, two => 2); # And this.
697 $c->session({ answer => 42 }); # And this.
699 =item session_expires
701 =item session_expires $reset
703 This method returns the time when the current session will expire, or 0 if
704 there is no current session. If there is a session and it already expired, it
705 will delete the session and return 0 as well.
707 If the C<$reset> parameter is true, and there is a session ID the expiry time
708 will be reset to the current time plus the time to live (see
709 L</CONFIGURATION>). This is used when creating a new session.
713 This is like Ruby on Rails' flash data structure. Think of it as a stash that
714 lasts for longer than one request, letting you redirect instead of forward.
716 The flash data will be cleaned up only on requests on which actually use
717 $c->flash (thus allowing multiple redirections), and the policy is to delete
718 all the keys which haven't changed since the flash data was loaded at the end
722 my ( $self, $c ) = @_;
724 $c->flash->{beans} = 10;
725 $c->response->redirect( $c->uri_for("foo") );
729 my ( $self, $c ) = @_;
731 my $value = $c->flash->{beans};
735 $c->response->redirect( $c->uri_for("bar") );
739 my ( $self, $c ) = @_;
741 if ( exists $c->flash->{beans} ) { # false
748 Zap all the keys in the flash regardless of their current state.
750 =item keep_flash @keys
752 If you want to keep a flash key for the next request too, even if it hasn't
753 changed, call C<keep_flash> and pass in the keys as arguments.
755 =item delete_session REASON
757 This method is used to invalidate a session. It takes an optional parameter
758 which will be saved in C<session_delete_reason> if provided.
760 NOTE: This method will B<also> delete your flash data.
762 =item session_delete_reason
764 This accessor contains a string with the reason a session was deleted. Possible
779 =item session_expire_key $key, $ttl
781 Mark a key to expire at a certain time (only useful when shorter than the
782 expiry time for the whole session).
786 __PACKAGE__->config('Plugin::Session' => { expires => 1000000000000 }); # forever
790 $c->session_expire_key( __user => 3600 );
792 Will make the session data survive, but the user will still be logged out after
795 Note that these values are not auto extended.
797 =item change_session_id
799 By calling this method you can force a session id change while keeping all
800 session data. This method might come handy when you are paranoid about some
801 advanced variations of session fixation attack.
803 If you want to prevent this session fixation scenario:
805 0) let us have WebApp with anonymous and authenticated parts
806 1) a hacker goes to vulnerable WebApp and gets a real sessionid,
807 just by browsing anonymous part of WebApp
808 2) the hacker inserts (somehow) this values into a cookie in victim's browser
809 3) after the victim logs into WebApp the hacker can enter his/her session
811 you should call change_session_id in your login controller like this:
813 if ($c->authenticate( { username => $user, password => $pass } )) {
815 $c->change_session_id;
824 =head1 INTERNAL METHODS
830 This method is extended to also make calls to
831 C<check_session_plugin_requirements> and C<setup_session>.
833 =item check_session_plugin_requirements
835 This method ensures that a State and a Store plugin are also in use by the
840 This method populates C<< $c->config('Plugin::Session') >> with the default values
841 listed in L</CONFIGURATION>.
845 This method is extended.
847 Its only effect is if the (off by default) C<flash_to_stash> configuration
848 parameter is on - then it will copy the contents of the flash to the stash at
851 =item finalize_headers
853 This method is extended and will extend the expiry time before sending
858 This method is extended and will call finalize_session before the other
859 finalize_body methods run. Here we persist the session data if a session exists.
861 =item initialize_session_data
863 This method will initialize the internal structure of the session, and is
864 called by the C<session> method if appropriate.
866 =item create_session_id
868 Creates a new session ID using C<generate_session_id> if there is no session ID
871 =item validate_session_id SID
873 Make sure a session ID is of the right format.
875 This currently ensures that the session ID string is any amount of case
876 insensitive hexadecimal characters.
878 =item generate_session_id
880 This method will return a string that can be used as a session ID. It is
881 supposed to be a reasonably random string with enough bits to prevent
882 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
883 MD5 or SHA-256, depending on the availability of these modules.
885 =item session_hash_seed
887 This method is actually rather internal to generate_session_id, but should be
888 overridable in case you want to provide more random data.
890 Currently it returns a concatenated string which contains:
896 =item * The current time
898 =item * One value from C<rand>.
900 =item * The stringified value of a newly allocated hash reference
902 =item * The stringified value of the Catalyst context object
906 in the hopes that those combined values are entropic enough for most uses. If
907 this is not the case you can replace C<session_hash_seed> with e.g.
909 sub session_hash_seed {
910 open my $fh, "<", "/dev/random";
911 read $fh, my $bytes, 20;
916 Or even more directly, replace C<generate_session_id>:
918 sub generate_session_id {
919 open my $fh, "<", "/dev/random";
920 read $fh, my $bytes, 20;
922 return unpack("H*", $bytes);
925 Also have a look at L<Crypt::Random> and the various openssl bindings - these
926 modules provide APIs for cryptographically secure random data.
928 =item finalize_session
930 Clean up the session during C<finalize>.
932 This clears the various accessors after saving to the store.
936 See L<Catalyst/dump_these> - ammends the session data structure to the list of
937 dumped objects if session ID is defined.
940 =item calculate_extended_session_expires
942 =item calculate_initial_session_expires
944 =item create_session_id_if_needed
946 =item delete_session_id
948 =item extend_session_expires
950 =item extend_session_id
954 =item reset_session_expires
956 =item session_is_valid
962 =head1 USING SESSIONS DURING PREPARE
964 The earliest point in time at which you may use the session data is after
965 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
967 State plugins must set $c->session ID before C<prepare_action>, and during
968 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
974 # don't touch $c->session yet!
976 $c->NEXT::prepare_action( @_ );
978 $c->session; # this is OK
979 $c->sessionid; # this is also OK
984 $c->config('Plugin::Session' => {
988 All configuation parameters are provided in a hash reference under the
989 C<Plugin::Session> key in the configuration hash.
995 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
1000 When true, C<<$c->request->address>> will be checked at prepare time. If it is
1001 not the same as the address that initiated the session, the session is deleted.
1005 =item verify_user_agent
1007 When true, C<<$c->request->user_agent>> will be checked at prepare time. If it
1008 is not the same as the user agent that initiated the session, the session is
1013 =item flash_to_stash
1015 This option makes it easier to have actions behave the same whether they were
1016 forwarded to or redirected to. On prepare time it copies the contents of
1017 C<flash> (if any) to the stash.
1023 The hash reference returned by C<< $c->session >> contains several keys which
1024 are automatically set:
1030 This key no longer exists. Use C<session_expires> instead.
1034 The last time a session was saved to the store.
1038 The time when the session was first created.
1042 The value of C<< $c->request->address >> at the time the session was created.
1043 This value is only populated if C<verify_address> is true in the configuration.
1047 The value of C<< $c->request->user_agent >> at the time the session was created.
1048 This value is only populated if C<verify_user_agent> is true in the configuration.
1054 =head2 Round the Robin Proxies
1056 C<verify_address> could make your site inaccessible to users who are behind
1057 load balanced proxies. Some ISPs may give a different IP to each request by the
1058 same client due to this type of proxying. If addresses are verified these
1059 users' sessions cannot persist.
1061 To let these users access your site you can either disable address verification
1062 as a whole, or provide a checkbox in the login dialog that tells the server
1063 that it's OK for the address of the client to change. When the server sees that
1064 this box is checked it should delete the C<__address> special key from the
1065 session hash when the hash is first created.
1067 =head2 Race Conditions
1069 In this day and age where cleaning detergents and Dutch football (not the
1070 American kind) teams roam the plains in great numbers, requests may happen
1071 simultaneously. This means that there is some risk of session data being
1072 overwritten, like this:
1078 request a starts, request b starts, with the same session ID
1082 session data is loaded in request a
1086 session data is loaded in request b
1090 session data is changed in request a
1094 request a finishes, session data is updated and written to store
1098 request b finishes, session data is updated and written to store, overwriting
1099 changes by request a
1103 If this is a concern in your application, a soon-to-be-developed locking
1104 solution is the only safe way to go. This will have a bigger overhead.
1106 For applications where any given user is only making one request at a time this
1107 plugin should be safe enough.
1115 Yuval Kogman, C<nothingmuch@woobling.org>
1119 Tomas Doran (t0m) C<bobtfish@bobtfish.net> (current maintainer)
1125 Florian Ragwitz (rafl) C<rafl@debian.org>
1127 Kent Fredric (kentnl)
1129 And countless other contributers from #catalyst. Thanks guys!
1131 =head1 COPYRIGHT & LICENSE
1133 Copyright (c) 2005 the aforementioned authors. All rights
1134 reserved. This program is free software; you can redistribute
1135 it and/or modify it under the same terms as Perl itself.