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 = '0.35';
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->extend_session_expires( $expires );
357 sub extend_session_expires {
358 my ( $c, $expires ) = @_;
359 $c->_extended_session_expires( my $updated = $c->calculate_initial_session_expires( $expires ) );
360 $c->extend_session_id( $c->sessionid, $updated );
364 sub change_session_expires {
365 my ( $c, $expires ) = @_;
368 my $sid = $c->sessionid;
369 my $time_exp = time() + $expires;
370 $c->store_session_data( "expires:$sid" => $time_exp );
373 sub initial_session_expires {
375 return ( time() + $c->_session_plugin_config->{expires} );
378 sub calculate_initial_session_expires {
381 my $initial_expires = $c->initial_session_expires;
382 my $stored_session_expires = 0;
383 if ( my $sid = $c->sessionid ) {
384 $stored_session_expires = $c->get_session_data("expires:$sid") || 0;
386 return ( $initial_expires > $stored_session_expires ) ? $initial_expires : $stored_session_expires;
389 sub calculate_extended_session_expires {
390 my ( $c, $prev ) = @_;
391 return ( time() + $prev );
394 sub reset_session_expires {
395 my ( $c, $sid ) = @_;
397 my $exp = $c->calculate_initial_session_expires;
398 $c->_session_expires( $exp );
400 # since we're setting _session_expires directly, make load_session_expires
401 # actually use that value.
403 $c->_tried_loading_session_expires(1);
404 $c->_extended_session_expires( $exp );
411 return $c->_sessionid || $c->_load_sessionid;
414 sub _load_sessionid {
416 return if $c->_tried_loading_session_id;
417 $c->_tried_loading_session_id(1);
419 if ( defined( my $sid = $c->get_session_id ) ) {
420 if ( $c->validate_session_id($sid) ) {
421 # temporarily set the inner key, so that validation will work
422 $c->_sessionid($sid);
425 my $err = "Tried to set invalid session ID '$sid'";
426 $c->log->error($err);
427 Catalyst::Exception->throw($err);
434 sub session_is_valid {
437 # force a check for expiry, but also __address, etc
438 if ( $c->_load_session ) {
445 sub validate_session_id {
446 my ( $c, $sid ) = @_;
448 $sid and $sid =~ /^[a-f\d]+$/i;
454 my $session = $c->_session || $c->_load_session || do {
455 $c->create_session_id_if_needed;
456 $c->initialize_session_data;
460 my $new_values = @_ > 1 ? { @_ } : $_[0];
461 croak('session takes a hash or hashref') unless ref $new_values;
463 for my $key (keys %$new_values) {
464 $session->{$key} = $new_values->{$key};
472 my ( $c, @keys ) = @_;
473 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
474 (@{$href}{@keys}) = ((undef) x @keys);
479 $c->_flash || $c->_load_flash || do {
480 $c->create_session_id_if_needed;
488 my $items = @_ > 1 ? {@_} : $_[0];
489 croak('flash takes a hash or hashref') unless ref $items;
490 @{ $c->_flash }{ keys %$items } = values %$items;
504 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
505 $c->_flash_key_hashes({});
506 $c->_flash_keep_keys({});
510 sub session_expire_key {
511 my ( $c, %keys ) = @_;
514 @{ $c->session->{__expire_keys} }{ keys %keys } =
515 map { $now + $_ } values %keys;
518 sub initialize_session_data {
529 $c->_session_plugin_config->{verify_address}
530 ? ( __address => $c->request->address||'' )
534 $c->_session_plugin_config->{verify_user_agent}
535 ? ( __user_agent => $c->request->user_agent||'' )
542 sub generate_session_id {
545 my $digest = $c->_find_digest();
546 $digest->add( $c->session_hash_seed() );
547 return $digest->hexdigest;
550 sub create_session_id_if_needed {
552 $c->create_session_id unless $c->sessionid;
555 sub create_session_id {
558 my $sid = $c->generate_session_id;
560 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
562 $c->_sessionid($sid);
563 $c->reset_session_expires;
564 $c->set_session_id($sid);
571 sub session_hash_seed {
574 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
579 sub _find_digest () {
581 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
582 if ( eval { Digest->new($alg) } ) {
587 Catalyst::Exception->throw(
588 "Could not find a suitable Digest module. Please install "
589 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
593 return Digest->new($usable);
600 $c->maybe::next::method(),
603 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
609 sub get_session_id { shift->maybe::next::method(@_) }
610 sub set_session_id { shift->maybe::next::method(@_) }
611 sub delete_session_id { shift->maybe::next::method(@_) }
612 sub extend_session_id { shift->maybe::next::method(@_) }
622 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
626 # To get sessions to "just work", all you need to do is use these plugins:
630 Session::Store::FastMmap
631 Session::State::Cookie
634 # you can replace Store::FastMmap with Store::File - both have sensible
635 # default configurations (see their docs for details)
637 # more complicated backends are available for other scenarios (DBI storage,
641 # after you've loaded the plugins you can save session data
642 # For example, if you are writing a shopping cart, it could be implemented
645 sub add_item : Local {
646 my ( $self, $c ) = @_;
648 my $item_id = $c->req->param("item");
650 # $c->session is a hash ref, a bit like $c->stash
651 # the difference is that it' preserved across requests
653 push @{ $c->session->{items} }, $item_id;
655 $c->forward("MyView");
658 sub display_items : Local {
659 my ( $self, $c ) = @_;
661 # values in $c->session are restored
662 $c->stash->{items_to_display} =
663 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
665 $c->forward("MyView");
670 The Session plugin is the base of two related parts of functionality required
671 for session management in web applications.
673 The first part, the State, is getting the browser to repeat back a session key,
674 so that the web application can identify the client and logically string
675 several requests together into a session.
677 The second part, the Store, deals with the actual storage of information about
678 the client. This data is stored so that the it may be revived for every request
679 made by the same client.
681 This plugin links the two pieces together.
683 =head1 RECOMENDED BACKENDS
687 =item Session::State::Cookie
689 The only really sane way to do state is using cookies.
691 =item Session::Store::File
693 A portable backend, based on Cache::File.
695 =item Session::Store::FastMmap
697 A fast and flexible backend, based on Cache::FastMmap.
707 An accessor for the session ID value.
711 Returns a hash reference that might contain unserialized values from previous
712 requests in the same session, and whose modified value will be saved for future
715 This method will automatically create a new session and session ID if none
718 You can also set session keys by passing a list of key/value pairs or a
721 $c->session->{foo} = "bar"; # This works.
722 $c->session(one => 1, two => 2); # And this.
723 $c->session({ answer => 42 }); # And this.
725 =item session_expires
727 This method returns the time when the current session will expire, or 0 if
728 there is no current session. If there is a session and it already expired, it
729 will delete the session and return 0 as well.
733 This is like Ruby on Rails' flash data structure. Think of it as a stash that
734 lasts for longer than one request, letting you redirect instead of forward.
736 The flash data will be cleaned up only on requests on which actually use
737 $c->flash (thus allowing multiple redirections), and the policy is to delete
738 all the keys which haven't changed since the flash data was loaded at the end
741 Note that use of the flash is an easy way to get data across requests, but
742 it's also strongly disrecommended, due it it being inherently plagued with
743 race conditions. This means that it's unlikely to work well if your
744 users have multiple tabs open at once, or if your site does a lot of AJAX
747 L<Catalyst::Plugin::StatusMessage> is the recommended alternative solution,
748 as this doesn't suffer from these issues.
751 my ( $self, $c ) = @_;
753 $c->flash->{beans} = 10;
754 $c->response->redirect( $c->uri_for("foo") );
758 my ( $self, $c ) = @_;
760 my $value = $c->flash->{beans};
764 $c->response->redirect( $c->uri_for("bar") );
768 my ( $self, $c ) = @_;
770 if ( exists $c->flash->{beans} ) { # false
777 Zap all the keys in the flash regardless of their current state.
779 =item keep_flash @keys
781 If you want to keep a flash key for the next request too, even if it hasn't
782 changed, call C<keep_flash> and pass in the keys as arguments.
784 =item delete_session REASON
786 This method is used to invalidate a session. It takes an optional parameter
787 which will be saved in C<session_delete_reason> if provided.
789 NOTE: This method will B<also> delete your flash data.
791 =item session_delete_reason
793 This accessor contains a string with the reason a session was deleted. Possible
808 =item session_expire_key $key, $ttl
810 Mark a key to expire at a certain time (only useful when shorter than the
811 expiry time for the whole session).
815 __PACKAGE__->config('Plugin::Session' => { expires => 10000000000 }); # "forever"
816 (NB If this number is too large, Y2K38 breakage could result.)
820 $c->session_expire_key( __user => 3600 );
822 Will make the session data survive, but the user will still be logged out after
825 Note that these values are not auto extended.
827 =item change_session_id
829 By calling this method you can force a session id change while keeping all
830 session data. This method might come handy when you are paranoid about some
831 advanced variations of session fixation attack.
833 If you want to prevent this session fixation scenario:
835 0) let us have WebApp with anonymous and authenticated parts
836 1) a hacker goes to vulnerable WebApp and gets a real sessionid,
837 just by browsing anonymous part of WebApp
838 2) the hacker inserts (somehow) this values into a cookie in victim's browser
839 3) after the victim logs into WebApp the hacker can enter his/her session
841 you should call change_session_id in your login controller like this:
843 if ($c->authenticate( { username => $user, password => $pass } )) {
845 $c->change_session_id;
852 =item change_session_expires $expires
854 You can change the session expiration time for this session;
856 $c->change_session_expires( 4000 );
858 Note that this only works to set the session longer than the config setting.
862 =head1 INTERNAL METHODS
868 This method is extended to also make calls to
869 C<check_session_plugin_requirements> and C<setup_session>.
871 =item check_session_plugin_requirements
873 This method ensures that a State and a Store plugin are also in use by the
878 This method populates C<< $c->config('Plugin::Session') >> with the default values
879 listed in L</CONFIGURATION>.
883 This method is extended.
885 Its only effect is if the (off by default) C<flash_to_stash> configuration
886 parameter is on - then it will copy the contents of the flash to the stash at
889 =item finalize_headers
891 This method is extended and will extend the expiry time before sending
896 This method is extended and will call finalize_session before the other
897 finalize_body methods run. Here we persist the session data if a session exists.
899 =item initialize_session_data
901 This method will initialize the internal structure of the session, and is
902 called by the C<session> method if appropriate.
904 =item create_session_id
906 Creates a new session ID using C<generate_session_id> if there is no session ID
909 =item validate_session_id SID
911 Make sure a session ID is of the right format.
913 This currently ensures that the session ID string is any amount of case
914 insensitive hexadecimal characters.
916 =item generate_session_id
918 This method will return a string that can be used as a session ID. It is
919 supposed to be a reasonably random string with enough bits to prevent
920 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
921 MD5 or SHA-256, depending on the availability of these modules.
923 =item session_hash_seed
925 This method is actually rather internal to generate_session_id, but should be
926 overridable in case you want to provide more random data.
928 Currently it returns a concatenated string which contains:
934 =item * The current time
936 =item * One value from C<rand>.
938 =item * The stringified value of a newly allocated hash reference
940 =item * The stringified value of the Catalyst context object
944 in the hopes that those combined values are entropic enough for most uses. If
945 this is not the case you can replace C<session_hash_seed> with e.g.
947 sub session_hash_seed {
948 open my $fh, "<", "/dev/random";
949 read $fh, my $bytes, 20;
954 Or even more directly, replace C<generate_session_id>:
956 sub generate_session_id {
957 open my $fh, "<", "/dev/random";
958 read $fh, my $bytes, 20;
960 return unpack("H*", $bytes);
963 Also have a look at L<Crypt::Random> and the various openssl bindings - these
964 modules provide APIs for cryptographically secure random data.
966 =item finalize_session
968 Clean up the session during C<finalize>.
970 This clears the various accessors after saving to the store.
974 See L<Catalyst/dump_these> - ammends the session data structure to the list of
975 dumped objects if session ID is defined.
978 =item calculate_extended_session_expires
980 =item calculate_initial_session_expires
982 =item create_session_id_if_needed
984 =item delete_session_id
986 =item extend_session_expires
988 Note: this is *not* used to give an individual user a longer session. See
989 'change_session_expires'.
991 =item extend_session_id
995 =item reset_session_expires
997 =item session_is_valid
1001 =item initial_session_expires
1005 =head1 USING SESSIONS DURING PREPARE
1007 The earliest point in time at which you may use the session data is after
1008 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
1010 State plugins must set $c->session ID before C<prepare_action>, and during
1011 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
1014 sub prepare_action {
1017 # don't touch $c->session yet!
1019 $c->NEXT::prepare_action( @_ );
1021 $c->session; # this is OK
1022 $c->sessionid; # this is also OK
1025 =head1 CONFIGURATION
1027 $c->config('Plugin::Session' => {
1031 All configuation parameters are provided in a hash reference under the
1032 C<Plugin::Session> key in the configuration hash.
1038 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
1041 =item verify_address
1043 When true, C<<$c->request->address>> will be checked at prepare time. If it is
1044 not the same as the address that initiated the session, the session is deleted.
1048 =item verify_user_agent
1050 When true, C<<$c->request->user_agent>> will be checked at prepare time. If it
1051 is not the same as the user agent that initiated the session, the session is
1056 =item flash_to_stash
1058 This option makes it easier to have actions behave the same whether they were
1059 forwarded to or redirected to. On prepare time it copies the contents of
1060 C<flash> (if any) to the stash.
1066 The hash reference returned by C<< $c->session >> contains several keys which
1067 are automatically set:
1073 This key no longer exists. Use C<session_expires> instead.
1077 The last time a session was saved to the store.
1081 The time when the session was first created.
1085 The value of C<< $c->request->address >> at the time the session was created.
1086 This value is only populated if C<verify_address> is true in the configuration.
1090 The value of C<< $c->request->user_agent >> at the time the session was created.
1091 This value is only populated if C<verify_user_agent> is true in the configuration.
1097 =head2 Round the Robin Proxies
1099 C<verify_address> could make your site inaccessible to users who are behind
1100 load balanced proxies. Some ISPs may give a different IP to each request by the
1101 same client due to this type of proxying. If addresses are verified these
1102 users' sessions cannot persist.
1104 To let these users access your site you can either disable address verification
1105 as a whole, or provide a checkbox in the login dialog that tells the server
1106 that it's OK for the address of the client to change. When the server sees that
1107 this box is checked it should delete the C<__address> special key from the
1108 session hash when the hash is first created.
1110 =head2 Race Conditions
1112 In this day and age where cleaning detergents and Dutch football (not the
1113 American kind) teams roam the plains in great numbers, requests may happen
1114 simultaneously. This means that there is some risk of session data being
1115 overwritten, like this:
1121 request a starts, request b starts, with the same session ID
1125 session data is loaded in request a
1129 session data is loaded in request b
1133 session data is changed in request a
1137 request a finishes, session data is updated and written to store
1141 request b finishes, session data is updated and written to store, overwriting
1142 changes by request a
1146 For applications where any given user's session is only making one request
1147 at a time this plugin should be safe enough.
1155 Yuval Kogman, C<nothingmuch@woobling.org>
1159 Tomas Doran (t0m) C<bobtfish@bobtfish.net> (current maintainer)
1165 Florian Ragwitz (rafl) C<rafl@debian.org>
1167 Kent Fredric (kentnl)
1169 And countless other contributers from #catalyst. Thanks guys!
1173 Devin Austin (dhoss) <dhoss@cpan.org>
1175 =head1 COPYRIGHT & LICENSE
1177 Copyright (c) 2005 the aforementioned authors. All rights
1178 reserved. This program is free software; you can redistribute
1179 it and/or modify it under the same terms as Perl itself.