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 = '0.26_01';
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 $c->_session || $c->_load_session || do {
429 $c->create_session_id_if_needed;
430 $c->initialize_session_data;
435 my ( $c, @keys ) = @_;
436 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
437 (@{$href}{@keys}) = ((undef) x @keys);
442 $c->_flash || $c->_load_flash || do {
443 $c->create_session_id_if_needed;
451 my $items = @_ > 1 ? {@_} : $_[0];
452 croak('flash takes a hash or hashref') unless ref $items;
453 @{ $c->_flash }{ keys %$items } = values %$items;
467 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
468 $c->_flash_key_hashes({});
469 $c->_flash_keep_keys({});
473 sub session_expire_key {
474 my ( $c, %keys ) = @_;
477 @{ $c->session->{__expire_keys} }{ keys %keys } =
478 map { $now + $_ } values %keys;
481 sub initialize_session_data {
492 $c->_session_plugin_config->{verify_address}
493 ? ( __address => $c->request->address||'' )
497 $c->_session_plugin_config->{verify_user_agent}
498 ? ( __user_agent => $c->request->user_agent||'' )
505 sub generate_session_id {
508 my $digest = $c->_find_digest();
509 $digest->add( $c->session_hash_seed() );
510 return $digest->hexdigest;
513 sub create_session_id_if_needed {
515 $c->create_session_id unless $c->sessionid;
518 sub create_session_id {
521 my $sid = $c->generate_session_id;
523 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
525 $c->_sessionid($sid);
526 $c->reset_session_expires;
527 $c->set_session_id($sid);
534 sub session_hash_seed {
537 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
542 sub _find_digest () {
544 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
545 if ( eval { Digest->new($alg) } ) {
550 Catalyst::Exception->throw(
551 "Could not find a suitable Digest module. Please install "
552 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
556 return Digest->new($usable);
563 $c->maybe::next::method(),
566 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
572 sub get_session_id { shift->maybe::next::method(@_) }
573 sub set_session_id { shift->maybe::next::method(@_) }
574 sub delete_session_id { shift->maybe::next::method(@_) }
575 sub extend_session_id { shift->maybe::next::method(@_) }
585 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
589 # To get sessions to "just work", all you need to do is use these plugins:
593 Session::Store::FastMmap
594 Session::State::Cookie
597 # you can replace Store::FastMmap with Store::File - both have sensible
598 # default configurations (see their docs for details)
600 # more complicated backends are available for other scenarios (DBI storage,
604 # after you've loaded the plugins you can save session data
605 # For example, if you are writing a shopping cart, it could be implemented
608 sub add_item : Local {
609 my ( $self, $c ) = @_;
611 my $item_id = $c->req->param("item");
613 # $c->session is a hash ref, a bit like $c->stash
614 # the difference is that it' preserved across requests
616 push @{ $c->session->{items} }, $item_id;
618 $c->forward("MyView");
621 sub display_items : Local {
622 my ( $self, $c ) = @_;
624 # values in $c->session are restored
625 $c->stash->{items_to_display} =
626 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
628 $c->forward("MyView");
633 The Session plugin is the base of two related parts of functionality required
634 for session management in web applications.
636 The first part, the State, is getting the browser to repeat back a session key,
637 so that the web application can identify the client and logically string
638 several requests together into a session.
640 The second part, the Store, deals with the actual storage of information about
641 the client. This data is stored so that the it may be revived for every request
642 made by the same client.
644 This plugin links the two pieces together.
646 =head1 RECOMENDED BACKENDS
650 =item Session::State::Cookie
652 The only really sane way to do state is using cookies.
654 =item Session::Store::File
656 A portable backend, based on Cache::File.
658 =item Session::Store::FastMmap
660 A fast and flexible backend, based on Cache::FastMmap.
670 An accessor for the session ID value.
674 Returns a hash reference that might contain unserialized values from previous
675 requests in the same session, and whose modified value will be saved for future
678 This method will automatically create a new session and session ID if none
681 =item session_expires
683 =item session_expires $reset
685 This method returns the time when the current session will expire, or 0 if
686 there is no current session. If there is a session and it already expired, it
687 will delete the session and return 0 as well.
689 If the C<$reset> parameter is true, and there is a session ID the expiry time
690 will be reset to the current time plus the time to live (see
691 L</CONFIGURATION>). This is used when creating a new session.
695 This is like Ruby on Rails' flash data structure. Think of it as a stash that
696 lasts for longer than one request, letting you redirect instead of forward.
698 The flash data will be cleaned up only on requests on which actually use
699 $c->flash (thus allowing multiple redirections), and the policy is to delete
700 all the keys which haven't changed since the flash data was loaded at the end
704 my ( $self, $c ) = @_;
706 $c->flash->{beans} = 10;
707 $c->response->redirect( $c->uri_for("foo") );
711 my ( $self, $c ) = @_;
713 my $value = $c->flash->{beans};
717 $c->response->redirect( $c->uri_for("bar") );
721 my ( $self, $c ) = @_;
723 if ( exists $c->flash->{beans} ) { # false
730 Zap all the keys in the flash regardless of their current state.
732 =item keep_flash @keys
734 If you want to keep a flash key for the next request too, even if it hasn't
735 changed, call C<keep_flash> and pass in the keys as arguments.
737 =item delete_session REASON
739 This method is used to invalidate a session. It takes an optional parameter
740 which will be saved in C<session_delete_reason> if provided.
742 NOTE: This method will B<also> delete your flash data.
744 =item session_delete_reason
746 This accessor contains a string with the reason a session was deleted. Possible
761 =item session_expire_key $key, $ttl
763 Mark a key to expire at a certain time (only useful when shorter than the
764 expiry time for the whole session).
768 __PACKAGE__->config('Plugin::Session' => { expires => 1000000000000 }); # forever
772 $c->session_expire_key( __user => 3600 );
774 Will make the session data survive, but the user will still be logged out after
777 Note that these values are not auto extended.
779 =item change_session_id
781 By calling this method you can force a session id change while keeping all
782 session data. This method might come handy when you are paranoid about some
783 advanced variations of session fixation attack.
785 If you want to prevent this session fixation scenario:
787 0) let us have WebApp with anonymous and authenticated parts
788 1) a hacker goes to vulnerable WebApp and gets a real sessionid,
789 just by browsing anonymous part of WebApp
790 2) the hacker inserts (somehow) this values into a cookie in victim's browser
791 3) after the victim logs into WebApp the hacker can enter his/her session
793 you should call change_session_id in your login controller like this:
795 if ($c->authenticate( { username => $user, password => $pass } )) {
797 $c->change_session_id;
806 =head1 INTERNAL METHODS
812 This method is extended to also make calls to
813 C<check_session_plugin_requirements> and C<setup_session>.
815 =item check_session_plugin_requirements
817 This method ensures that a State and a Store plugin are also in use by the
822 This method populates C<< $c->config('Plugin::Session') >> with the default values
823 listed in L</CONFIGURATION>.
827 This method is extended.
829 Its only effect is if the (off by default) C<flash_to_stash> configuration
830 parameter is on - then it will copy the contents of the flash to the stash at
833 =item finalize_headers
835 This method is extended and will extend the expiry time before sending
840 This method is extended and will call finalize_session before the other
841 finalize_body methods run. Here we persist the session data if a session exists.
843 =item initialize_session_data
845 This method will initialize the internal structure of the session, and is
846 called by the C<session> method if appropriate.
848 =item create_session_id
850 Creates a new session ID using C<generate_session_id> if there is no session ID
853 =item validate_session_id SID
855 Make sure a session ID is of the right format.
857 This currently ensures that the session ID string is any amount of case
858 insensitive hexadecimal characters.
860 =item generate_session_id
862 This method will return a string that can be used as a session ID. It is
863 supposed to be a reasonably random string with enough bits to prevent
864 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
865 MD5 or SHA-256, depending on the availability of these modules.
867 =item session_hash_seed
869 This method is actually rather internal to generate_session_id, but should be
870 overridable in case you want to provide more random data.
872 Currently it returns a concatenated string which contains:
878 =item * The current time
880 =item * One value from C<rand>.
882 =item * The stringified value of a newly allocated hash reference
884 =item * The stringified value of the Catalyst context object
888 in the hopes that those combined values are entropic enough for most uses. If
889 this is not the case you can replace C<session_hash_seed> with e.g.
891 sub session_hash_seed {
892 open my $fh, "<", "/dev/random";
893 read $fh, my $bytes, 20;
898 Or even more directly, replace C<generate_session_id>:
900 sub generate_session_id {
901 open my $fh, "<", "/dev/random";
902 read $fh, my $bytes, 20;
904 return unpack("H*", $bytes);
907 Also have a look at L<Crypt::Random> and the various openssl bindings - these
908 modules provide APIs for cryptographically secure random data.
910 =item finalize_session
912 Clean up the session during C<finalize>.
914 This clears the various accessors after saving to the store.
918 See L<Catalyst/dump_these> - ammends the session data structure to the list of
919 dumped objects if session ID is defined.
922 =item calculate_extended_session_expires
924 =item calculate_initial_session_expires
926 =item create_session_id_if_needed
928 =item delete_session_id
930 =item extend_session_expires
932 =item extend_session_id
936 =item reset_session_expires
938 =item session_is_valid
944 =head1 USING SESSIONS DURING PREPARE
946 The earliest point in time at which you may use the session data is after
947 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
949 State plugins must set $c->session ID before C<prepare_action>, and during
950 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
956 # don't touch $c->session yet!
958 $c->NEXT::prepare_action( @_ );
960 $c->session; # this is OK
961 $c->sessionid; # this is also OK
966 $c->config('Plugin::Session' => {
970 All configuation parameters are provided in a hash reference under the
971 C<Plugin::Session> key in the configuration hash.
977 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
982 When true, C<<$c->request->address>> will be checked at prepare time. If it is
983 not the same as the address that initiated the session, the session is deleted.
987 =item verify_user_agent
989 When true, C<<$c->request->user_agent>> will be checked at prepare time. If it
990 is not the same as the user agent that initiated the session, the session is
997 This option makes it easier to have actions behave the same whether they were
998 forwarded to or redirected to. On prepare time it copies the contents of
999 C<flash> (if any) to the stash.
1005 The hash reference returned by C<< $c->session >> contains several keys which
1006 are automatically set:
1012 This key no longer exists. Use C<session_expires> instead.
1016 The last time a session was saved to the store.
1020 The time when the session was first created.
1024 The value of C<< $c->request->address >> at the time the session was created.
1025 This value is only populated if C<verify_address> is true in the configuration.
1029 The value of C<< $c->request->user_agent >> at the time the session was created.
1030 This value is only populated if C<verify_user_agent> is true in the configuration.
1036 =head2 Round the Robin Proxies
1038 C<verify_address> could make your site inaccessible to users who are behind
1039 load balanced proxies. Some ISPs may give a different IP to each request by the
1040 same client due to this type of proxying. If addresses are verified these
1041 users' sessions cannot persist.
1043 To let these users access your site you can either disable address verification
1044 as a whole, or provide a checkbox in the login dialog that tells the server
1045 that it's OK for the address of the client to change. When the server sees that
1046 this box is checked it should delete the C<__address> special key from the
1047 session hash when the hash is first created.
1049 =head2 Race Conditions
1051 In this day and age where cleaning detergents and Dutch football (not the
1052 American kind) teams roam the plains in great numbers, requests may happen
1053 simultaneously. This means that there is some risk of session data being
1054 overwritten, like this:
1060 request a starts, request b starts, with the same session ID
1064 session data is loaded in request a
1068 session data is loaded in request b
1072 session data is changed in request a
1076 request a finishes, session data is updated and written to store
1080 request b finishes, session data is updated and written to store, overwriting
1081 changes by request a
1085 If this is a concern in your application, a soon-to-be-developed locking
1086 solution is the only safe way to go. This will have a bigger overhead.
1088 For applications where any given user is only making one request at a time this
1089 plugin should be safe enough.
1097 Yuval Kogman, C<nothingmuch@woobling.org>
1101 Tomas Doran (t0m) C<bobtfish@bobtfish.net> (current maintainer)
1107 And countless other contributers from #catalyst. Thanks guys!
1109 =head1 COPYRIGHT & LICENSE
1111 Copyright (c) 2005 the aforementioned authors. All rights
1112 reserved. This program is free software; you can redistribute
1113 it and/or modify it under the same terms as Perl itself.