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 = '0.34';
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 # Force extension of session_expires before finalizing headers, so a possible cookie will be
106 # up to date. First call to session_expires will extend the expiry, subsequent calls will
107 # just return the previously extended value.
110 return $c->maybe::next::method(@_);
116 # We have to finalize our session *before* $c->engine->finalize_xxx is called,
117 # because we do not want to send the HTTP response before the session is stored/committed to
118 # the session database (or whatever Session::Store you use).
119 $c->finalize_session;
121 return $c->maybe::next::method(@_);
124 sub finalize_session {
127 $c->maybe::next::method(@_);
129 $c->_save_session_expires;
130 $c->_save_session_id;
134 $c->_clear_session_instance_data;
137 sub _save_session_id {
140 # we already called set when allocating
141 # no need to tell the state plugins anything new
144 sub _save_session_expires {
147 if ( defined($c->_session_expires) ) {
148 my $expires = $c->session_expires; # force extension
150 my $sid = $c->sessionid;
151 $c->store_session_data( "expires:$sid" => $expires );
158 if ( my $session_data = $c->_session ) {
160 no warnings 'uninitialized';
161 if ( Object::Signature::signature($session_data) ne
162 $c->_session_data_sig )
164 $session_data->{__updated} = time();
165 my $sid = $c->sessionid;
166 $c->store_session_data( "session:$sid" => $session_data );
174 if ( my $flash_data = $c->_flash ) {
176 my $hashes = $c->_flash_key_hashes || {};
177 my $keep = $c->_flash_keep_keys || {};
178 foreach my $key ( keys %$hashes ) {
179 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
180 delete $flash_data->{$key};
184 my $sid = $c->sessionid;
186 my $session_data = $c->_session;
188 $session_data->{__flash} = $flash_data;
191 delete $session_data->{__flash};
193 $c->_session($session_data);
198 sub _load_session_expires {
200 return $c->_session_expires if $c->_tried_loading_session_expires;
201 $c->_tried_loading_session_expires(1);
203 if ( my $sid = $c->sessionid ) {
204 my $expires = $c->get_session_data("expires:$sid") || 0;
206 if ( $expires >= time() ) {
207 $c->_session_expires( $expires );
210 $c->delete_session( "session expired" );
220 return $c->_session if $c->_tried_loading_session_data;
221 $c->_tried_loading_session_data(1);
223 if ( my $sid = $c->sessionid ) {
224 if ( $c->_load_session_expires ) { # > 0
226 my $session_data = $c->get_session_data("session:$sid") || return;
227 $c->_session($session_data);
229 no warnings 'uninitialized'; # ne __address
230 if ( $c->_session_plugin_config->{verify_address}
231 && exists $session_data->{__address}
232 && $session_data->{__address} ne $c->request->address )
235 "Deleting session $sid due to address mismatch ("
236 . $session_data->{__address} . " != "
237 . $c->request->address . ")"
239 $c->delete_session("address mismatch");
242 if ( $c->_session_plugin_config->{verify_user_agent}
243 && $session_data->{__user_agent} ne $c->request->user_agent )
246 "Deleting session $sid due to user agent mismatch ("
247 . $session_data->{__user_agent} . " != "
248 . $c->request->user_agent . ")"
250 $c->delete_session("user agent mismatch");
254 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
255 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
256 $c->_expire_session_keys;
258 return $session_data;
267 return $c->_flash if $c->_tried_loading_flash_data;
268 $c->_tried_loading_flash_data(1);
270 if ( my $sid = $c->sessionid ) {
272 my $session_data = $c->session;
273 $c->_flash($session_data->{__flash});
275 if ( my $flash_data = $c->_flash )
277 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
286 sub _expire_session_keys {
287 my ( $c, $data ) = @_;
291 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
292 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
293 delete $c->_session->{$key};
294 delete $expire_times->{$key};
298 sub _clear_session_instance_data {
300 $c->$_(undef) for @session_data_accessors;
301 $c->maybe::next::method(@_); # allow other plugins to hook in on this
304 sub change_session_id {
307 my $sessiondata = $c->session;
308 my $oldsid = $c->sessionid;
309 my $newsid = $c->create_session_id;
312 $c->log->debug(qq/change_sessid: deleting session data from "$oldsid"/) if $c->debug;
313 $c->delete_session_data("${_}:${oldsid}") for qw/session expires flash/;
316 $c->log->debug(qq/change_sessid: storing session data to "$newsid"/) if $c->debug;
317 $c->store_session_data( "session:$newsid" => $sessiondata );
323 my ( $c, $msg ) = @_;
325 $c->log->debug("Deleting session" . ( defined($msg) ? "($msg)" : '(no reason given)') ) if $c->debug;
327 # delete the session data
328 if ( my $sid = $c->sessionid ) {
329 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
330 $c->delete_session_id($sid);
333 # reset the values in the context object
334 # see the BEGIN block
335 $c->_clear_session_instance_data;
337 $c->_session_delete_reason($msg);
340 sub session_delete_reason {
343 $c->session_is_valid; # check that it was loaded
345 $c->_session_delete_reason(@_);
348 sub session_expires {
351 if ( defined( my $expires = $c->_extended_session_expires ) ) {
353 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
354 return $c->extend_session_expires( $expires );
360 sub extend_session_expires {
361 my ( $c, $expires ) = @_;
362 $c->_extended_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
363 $c->extend_session_id( $c->sessionid, $updated );
367 sub calculate_initial_session_expires {
369 return ( time() + $c->_session_plugin_config->{expires} );
372 sub calculate_extended_session_expires {
373 my ( $c, $prev ) = @_;
374 return ( time() + $prev );
377 sub reset_session_expires {
378 my ( $c, $sid ) = @_;
380 my $exp = $c->calculate_initial_session_expires;
381 $c->_session_expires( $exp );
383 # since we're setting _session_expires directly, make load_session_expires
384 # actually use that value.
386 $c->_tried_loading_session_expires(1);
387 $c->_extended_session_expires( $exp );
394 return $c->_sessionid || $c->_load_sessionid;
397 sub _load_sessionid {
399 return if $c->_tried_loading_session_id;
400 $c->_tried_loading_session_id(1);
402 if ( defined( my $sid = $c->get_session_id ) ) {
403 if ( $c->validate_session_id($sid) ) {
404 # temporarily set the inner key, so that validation will work
405 $c->_sessionid($sid);
408 my $err = "Tried to set invalid session ID '$sid'";
409 $c->log->error($err);
410 Catalyst::Exception->throw($err);
417 sub session_is_valid {
420 # force a check for expiry, but also __address, etc
421 if ( $c->_load_session ) {
428 sub validate_session_id {
429 my ( $c, $sid ) = @_;
431 $sid and $sid =~ /^[a-f\d]+$/i;
437 my $session = $c->_session || $c->_load_session || do {
438 $c->create_session_id_if_needed;
439 $c->initialize_session_data;
443 my $new_values = @_ > 1 ? { @_ } : $_[0];
444 croak('session takes a hash or hashref') unless ref $new_values;
446 for my $key (keys %$new_values) {
447 $session->{$key} = $new_values->{$key};
455 my ( $c, @keys ) = @_;
456 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
457 (@{$href}{@keys}) = ((undef) x @keys);
462 $c->_flash || $c->_load_flash || do {
463 $c->create_session_id_if_needed;
471 my $items = @_ > 1 ? {@_} : $_[0];
472 croak('flash takes a hash or hashref') unless ref $items;
473 @{ $c->_flash }{ keys %$items } = values %$items;
487 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
488 $c->_flash_key_hashes({});
489 $c->_flash_keep_keys({});
493 sub session_expire_key {
494 my ( $c, %keys ) = @_;
497 @{ $c->session->{__expire_keys} }{ keys %keys } =
498 map { $now + $_ } values %keys;
501 sub initialize_session_data {
512 $c->_session_plugin_config->{verify_address}
513 ? ( __address => $c->request->address||'' )
517 $c->_session_plugin_config->{verify_user_agent}
518 ? ( __user_agent => $c->request->user_agent||'' )
525 sub generate_session_id {
528 my $digest = $c->_find_digest();
529 $digest->add( $c->session_hash_seed() );
530 return $digest->hexdigest;
533 sub create_session_id_if_needed {
535 $c->create_session_id unless $c->sessionid;
538 sub create_session_id {
541 my $sid = $c->generate_session_id;
543 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
545 $c->_sessionid($sid);
546 $c->reset_session_expires;
547 $c->set_session_id($sid);
554 sub session_hash_seed {
557 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
562 sub _find_digest () {
564 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
565 if ( eval { Digest->new($alg) } ) {
570 Catalyst::Exception->throw(
571 "Could not find a suitable Digest module. Please install "
572 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
576 return Digest->new($usable);
583 $c->maybe::next::method(),
586 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
592 sub get_session_id { shift->maybe::next::method(@_) }
593 sub set_session_id { shift->maybe::next::method(@_) }
594 sub delete_session_id { shift->maybe::next::method(@_) }
595 sub extend_session_id { shift->maybe::next::method(@_) }
605 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
609 # To get sessions to "just work", all you need to do is use these plugins:
613 Session::Store::FastMmap
614 Session::State::Cookie
617 # you can replace Store::FastMmap with Store::File - both have sensible
618 # default configurations (see their docs for details)
620 # more complicated backends are available for other scenarios (DBI storage,
624 # after you've loaded the plugins you can save session data
625 # For example, if you are writing a shopping cart, it could be implemented
628 sub add_item : Local {
629 my ( $self, $c ) = @_;
631 my $item_id = $c->req->param("item");
633 # $c->session is a hash ref, a bit like $c->stash
634 # the difference is that it' preserved across requests
636 push @{ $c->session->{items} }, $item_id;
638 $c->forward("MyView");
641 sub display_items : Local {
642 my ( $self, $c ) = @_;
644 # values in $c->session are restored
645 $c->stash->{items_to_display} =
646 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
648 $c->forward("MyView");
653 The Session plugin is the base of two related parts of functionality required
654 for session management in web applications.
656 The first part, the State, is getting the browser to repeat back a session key,
657 so that the web application can identify the client and logically string
658 several requests together into a session.
660 The second part, the Store, deals with the actual storage of information about
661 the client. This data is stored so that the it may be revived for every request
662 made by the same client.
664 This plugin links the two pieces together.
666 =head1 RECOMENDED BACKENDS
670 =item Session::State::Cookie
672 The only really sane way to do state is using cookies.
674 =item Session::Store::File
676 A portable backend, based on Cache::File.
678 =item Session::Store::FastMmap
680 A fast and flexible backend, based on Cache::FastMmap.
690 An accessor for the session ID value.
694 Returns a hash reference that might contain unserialized values from previous
695 requests in the same session, and whose modified value will be saved for future
698 This method will automatically create a new session and session ID if none
701 You can also set session keys by passing a list of key/value pairs or a
704 $c->session->{foo} = "bar"; # This works.
705 $c->session(one => 1, two => 2); # And this.
706 $c->session({ answer => 42 }); # And this.
708 =item session_expires
710 This method returns the time when the current session will expire, or 0 if
711 there is no current session. If there is a session and it already expired, it
712 will delete the session and return 0 as well.
716 This is like Ruby on Rails' flash data structure. Think of it as a stash that
717 lasts for longer than one request, letting you redirect instead of forward.
719 The flash data will be cleaned up only on requests on which actually use
720 $c->flash (thus allowing multiple redirections), and the policy is to delete
721 all the keys which haven't changed since the flash data was loaded at the end
724 Note that use of the flash is an easy way to get data across requests, but
725 it's also strongly disrecommended, due it it being inherently plagued with
726 race conditions. This means that it's unlikely to work well if your
727 users have multiple tabs open at once, or if your site does a lot of AJAX
730 L<Catalyst::Plugin::StatusMessage> is the recommended alternative solution,
731 as this doesn't suffer from these issues.
734 my ( $self, $c ) = @_;
736 $c->flash->{beans} = 10;
737 $c->response->redirect( $c->uri_for("foo") );
741 my ( $self, $c ) = @_;
743 my $value = $c->flash->{beans};
747 $c->response->redirect( $c->uri_for("bar") );
751 my ( $self, $c ) = @_;
753 if ( exists $c->flash->{beans} ) { # false
760 Zap all the keys in the flash regardless of their current state.
762 =item keep_flash @keys
764 If you want to keep a flash key for the next request too, even if it hasn't
765 changed, call C<keep_flash> and pass in the keys as arguments.
767 =item delete_session REASON
769 This method is used to invalidate a session. It takes an optional parameter
770 which will be saved in C<session_delete_reason> if provided.
772 NOTE: This method will B<also> delete your flash data.
774 =item session_delete_reason
776 This accessor contains a string with the reason a session was deleted. Possible
791 =item session_expire_key $key, $ttl
793 Mark a key to expire at a certain time (only useful when shorter than the
794 expiry time for the whole session).
798 __PACKAGE__->config('Plugin::Session' => { expires => 10000000000 }); # "forever"
799 (NB If this number is too large, Y2K38 breakage could result.)
803 $c->session_expire_key( __user => 3600 );
805 Will make the session data survive, but the user will still be logged out after
808 Note that these values are not auto extended.
810 =item change_session_id
812 By calling this method you can force a session id change while keeping all
813 session data. This method might come handy when you are paranoid about some
814 advanced variations of session fixation attack.
816 If you want to prevent this session fixation scenario:
818 0) let us have WebApp with anonymous and authenticated parts
819 1) a hacker goes to vulnerable WebApp and gets a real sessionid,
820 just by browsing anonymous part of WebApp
821 2) the hacker inserts (somehow) this values into a cookie in victim's browser
822 3) after the victim logs into WebApp the hacker can enter his/her session
824 you should call change_session_id in your login controller like this:
826 if ($c->authenticate( { username => $user, password => $pass } )) {
828 $c->change_session_id;
837 =head1 INTERNAL METHODS
843 This method is extended to also make calls to
844 C<check_session_plugin_requirements> and C<setup_session>.
846 =item check_session_plugin_requirements
848 This method ensures that a State and a Store plugin are also in use by the
853 This method populates C<< $c->config('Plugin::Session') >> with the default values
854 listed in L</CONFIGURATION>.
858 This method is extended.
860 Its only effect is if the (off by default) C<flash_to_stash> configuration
861 parameter is on - then it will copy the contents of the flash to the stash at
864 =item finalize_headers
866 This method is extended and will extend the expiry time before sending
871 This method is extended and will call finalize_session before the other
872 finalize_body methods run. Here we persist the session data if a session exists.
874 =item initialize_session_data
876 This method will initialize the internal structure of the session, and is
877 called by the C<session> method if appropriate.
879 =item create_session_id
881 Creates a new session ID using C<generate_session_id> if there is no session ID
884 =item validate_session_id SID
886 Make sure a session ID is of the right format.
888 This currently ensures that the session ID string is any amount of case
889 insensitive hexadecimal characters.
891 =item generate_session_id
893 This method will return a string that can be used as a session ID. It is
894 supposed to be a reasonably random string with enough bits to prevent
895 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
896 MD5 or SHA-256, depending on the availability of these modules.
898 =item session_hash_seed
900 This method is actually rather internal to generate_session_id, but should be
901 overridable in case you want to provide more random data.
903 Currently it returns a concatenated string which contains:
909 =item * The current time
911 =item * One value from C<rand>.
913 =item * The stringified value of a newly allocated hash reference
915 =item * The stringified value of the Catalyst context object
919 in the hopes that those combined values are entropic enough for most uses. If
920 this is not the case you can replace C<session_hash_seed> with e.g.
922 sub session_hash_seed {
923 open my $fh, "<", "/dev/random";
924 read $fh, my $bytes, 20;
929 Or even more directly, replace C<generate_session_id>:
931 sub generate_session_id {
932 open my $fh, "<", "/dev/random";
933 read $fh, my $bytes, 20;
935 return unpack("H*", $bytes);
938 Also have a look at L<Crypt::Random> and the various openssl bindings - these
939 modules provide APIs for cryptographically secure random data.
941 =item finalize_session
943 Clean up the session during C<finalize>.
945 This clears the various accessors after saving to the store.
949 See L<Catalyst/dump_these> - ammends the session data structure to the list of
950 dumped objects if session ID is defined.
953 =item calculate_extended_session_expires
955 =item calculate_initial_session_expires
957 =item create_session_id_if_needed
959 =item delete_session_id
961 =item extend_session_expires
963 =item extend_session_id
967 =item reset_session_expires
969 =item session_is_valid
975 =head1 USING SESSIONS DURING PREPARE
977 The earliest point in time at which you may use the session data is after
978 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
980 State plugins must set $c->session ID before C<prepare_action>, and during
981 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
987 # don't touch $c->session yet!
989 $c->NEXT::prepare_action( @_ );
991 $c->session; # this is OK
992 $c->sessionid; # this is also OK
997 $c->config('Plugin::Session' => {
1001 All configuation parameters are provided in a hash reference under the
1002 C<Plugin::Session> key in the configuration hash.
1008 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
1011 =item verify_address
1013 When true, C<<$c->request->address>> will be checked at prepare time. If it is
1014 not the same as the address that initiated the session, the session is deleted.
1018 =item verify_user_agent
1020 When true, C<<$c->request->user_agent>> will be checked at prepare time. If it
1021 is not the same as the user agent that initiated the session, the session is
1026 =item flash_to_stash
1028 This option makes it easier to have actions behave the same whether they were
1029 forwarded to or redirected to. On prepare time it copies the contents of
1030 C<flash> (if any) to the stash.
1036 The hash reference returned by C<< $c->session >> contains several keys which
1037 are automatically set:
1043 This key no longer exists. Use C<session_expires> instead.
1047 The last time a session was saved to the store.
1051 The time when the session was first created.
1055 The value of C<< $c->request->address >> at the time the session was created.
1056 This value is only populated if C<verify_address> is true in the configuration.
1060 The value of C<< $c->request->user_agent >> at the time the session was created.
1061 This value is only populated if C<verify_user_agent> is true in the configuration.
1067 =head2 Round the Robin Proxies
1069 C<verify_address> could make your site inaccessible to users who are behind
1070 load balanced proxies. Some ISPs may give a different IP to each request by the
1071 same client due to this type of proxying. If addresses are verified these
1072 users' sessions cannot persist.
1074 To let these users access your site you can either disable address verification
1075 as a whole, or provide a checkbox in the login dialog that tells the server
1076 that it's OK for the address of the client to change. When the server sees that
1077 this box is checked it should delete the C<__address> special key from the
1078 session hash when the hash is first created.
1080 =head2 Race Conditions
1082 In this day and age where cleaning detergents and Dutch football (not the
1083 American kind) teams roam the plains in great numbers, requests may happen
1084 simultaneously. This means that there is some risk of session data being
1085 overwritten, like this:
1091 request a starts, request b starts, with the same session ID
1095 session data is loaded in request a
1099 session data is loaded in request b
1103 session data is changed in request a
1107 request a finishes, session data is updated and written to store
1111 request b finishes, session data is updated and written to store, overwriting
1112 changes by request a
1116 For applications where any given user's session is only making one request
1117 at a time this plugin should be safe enough.
1125 Yuval Kogman, C<nothingmuch@woobling.org>
1129 Tomas Doran (t0m) C<bobtfish@bobtfish.net> (current maintainer)
1135 Florian Ragwitz (rafl) C<rafl@debian.org>
1137 Kent Fredric (kentnl)
1139 And countless other contributers from #catalyst. Thanks guys!
1143 Devin Austin (dhoss) <dhoss@cpan.org>
1145 =head1 COPYRIGHT & LICENSE
1147 Copyright (c) 2005 the aforementioned authors. All rights
1148 reserved. This program is free software; you can redistribute
1149 it and/or modify it under the same terms as Perl itself.