3 package Catalyst::Plugin::Session;
6 with 'MooseX::Emulate::Class::Accessor::Fast';
8 use Catalyst::Exception ();
11 use Object::Signature ();
13 use List::Util qw/ max /;
15 use namespace::clean -except => 'meta';
17 our $VERSION = '0.37';
18 $VERSION = eval $VERSION;
20 my @session_data_accessors; # used in delete_session
22 __PACKAGE__->mk_accessors(
23 "_session_delete_reason",
24 @session_data_accessors = qw/
28 _extended_session_expires
33 _tried_loading_session_id
34 _tried_loading_session_data
35 _tried_loading_session_expires
36 _tried_loading_flash_data
40 sub _session_plugin_config {
42 # FIXME - Start warning once all the state/store modules have also been updated.
43 #$c->log->warn("Deprecated 'session' config key used, please use the key 'Plugin::Session' instead")
44 # if exists $c->config->{session}
45 #$c->config->{'Plugin::Session'} ||= delete($c->config->{session}) || {};
46 $c->config->{'Plugin::Session'} ||= $c->config->{session} || {};
52 $c->maybe::next::method(@_);
54 $c->check_session_plugin_requirements;
60 sub check_session_plugin_requirements {
63 unless ( $c->isa("Catalyst::Plugin::Session::State")
64 && $c->isa("Catalyst::Plugin::Session::Store") )
67 ( "The Session plugin requires both Session::State "
68 . "and Session::Store plugins to be used as well." );
71 Catalyst::Exception->throw($err);
78 my $cfg = $c->_session_plugin_config;
83 verify_user_agent => 0,
84 expiry_threshold => 0,
88 $c->maybe::next::method();
94 $c->maybe::next::method(@_);
96 if ( $c->_session_plugin_config->{flash_to_stash}
98 and my $flash_data = $c->flash )
100 @{ $c->stash }{ keys %$flash_data } = values %$flash_data;
104 sub finalize_headers {
107 # fix cookie before we send headers
108 $c->_save_session_expires;
110 # Force extension of session_expires before finalizing headers, so a pos
111 # up to date. First call to session_expires will extend the expiry, subs
112 # just return the previously extended value.
115 return $c->maybe::next::method(@_);
121 # We have to finalize our session *before* $c->engine->finalize_xxx is called,
122 # because we do not want to send the HTTP response before the session is stored/committed to
123 # the session database (or whatever Session::Store you use).
124 $c->finalize_session;
126 return $c->maybe::next::method(@_);
129 sub finalize_session {
132 $c->maybe::next::method(@_);
134 $c->_save_session_id;
138 $c->_clear_session_instance_data;
141 sub _save_session_id {
144 # we already called set when allocating
145 # no need to tell the state plugins anything new
148 sub _save_session_expires {
151 if ( defined($c->_session_expires) ) {
153 my $threshold = $c->_session_plugin_config->{expiry_threshold} || 0;
155 if ( my $sid = $c->sessionid ) {
156 my $cutoff = $c->_get_stored_session_expires - $threshold;
158 if (!$threshold || $cutoff <= time) {
159 my $expires = $c->session_expires; # force extension
160 $c->store_session_data( "expires:$sid" => $expires );
172 if ( my $session_data = $c->_session ) {
174 no warnings 'uninitialized';
175 if ( Object::Signature::signature($session_data) ne
176 $c->_session_data_sig )
178 $session_data->{__updated} = time();
179 my $sid = $c->sessionid;
180 $c->store_session_data( "session:$sid" => $session_data );
188 if ( my $flash_data = $c->_flash ) {
190 my $hashes = $c->_flash_key_hashes || {};
191 my $keep = $c->_flash_keep_keys || {};
192 foreach my $key ( keys %$hashes ) {
193 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
194 delete $flash_data->{$key};
198 my $sid = $c->sessionid;
200 my $session_data = $c->_session;
202 $session_data->{__flash} = $flash_data;
205 delete $session_data->{__flash};
207 $c->_session($session_data);
212 sub _load_session_expires {
214 return $c->_session_expires if $c->_tried_loading_session_expires;
215 $c->_tried_loading_session_expires(1);
217 if ( my $sid = $c->sessionid ) {
218 my $expires = $c->_get_stored_session_expires;
220 if ( $expires >= time() ) {
221 $c->_session_expires( $expires );
224 $c->delete_session( "session expired" );
234 return $c->_session if $c->_tried_loading_session_data;
235 $c->_tried_loading_session_data(1);
237 if ( my $sid = $c->sessionid ) {
238 if ( $c->_load_session_expires ) { # > 0
240 my $session_data = $c->get_session_data("session:$sid") || return;
241 $c->_session($session_data);
243 no warnings 'uninitialized'; # ne __address
244 if ( $c->_session_plugin_config->{verify_address}
245 && exists $session_data->{__address}
246 && $session_data->{__address} ne $c->request->address )
249 "Deleting session $sid due to address mismatch ("
250 . $session_data->{__address} . " != "
251 . $c->request->address . ")"
253 $c->delete_session("address mismatch");
256 if ( $c->_session_plugin_config->{verify_user_agent}
257 && $session_data->{__user_agent} ne $c->request->user_agent )
260 "Deleting session $sid due to user agent mismatch ("
261 . $session_data->{__user_agent} . " != "
262 . $c->request->user_agent . ")"
264 $c->delete_session("user agent mismatch");
268 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
269 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
270 $c->_expire_session_keys;
272 return $session_data;
281 return $c->_flash if $c->_tried_loading_flash_data;
282 $c->_tried_loading_flash_data(1);
284 if ( my $sid = $c->sessionid ) {
286 my $session_data = $c->session;
287 $c->_flash($session_data->{__flash});
289 if ( my $flash_data = $c->_flash )
291 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
300 sub _expire_session_keys {
301 my ( $c, $data ) = @_;
305 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
306 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
307 delete $c->_session->{$key};
308 delete $expire_times->{$key};
312 sub _clear_session_instance_data {
314 $c->$_(undef) for @session_data_accessors;
315 $c->maybe::next::method(@_); # allow other plugins to hook in on this
318 sub change_session_id {
321 my $sessiondata = $c->session;
322 my $oldsid = $c->sessionid;
323 my $newsid = $c->create_session_id;
326 $c->log->debug(qq/change_sessid: deleting session data from "$oldsid"/) if $c->debug;
327 $c->delete_session_data("${_}:${oldsid}") for qw/session expires flash/;
330 $c->log->debug(qq/change_sessid: storing session data to "$newsid"/) if $c->debug;
331 $c->store_session_data( "session:$newsid" => $sessiondata );
337 my ( $c, $msg ) = @_;
339 $c->log->debug("Deleting session" . ( defined($msg) ? "($msg)" : '(no reason given)') ) if $c->debug;
341 # delete the session data
342 if ( my $sid = $c->sessionid ) {
343 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
344 $c->delete_session_id($sid);
347 # reset the values in the context object
348 # see the BEGIN block
349 $c->_clear_session_instance_data;
351 $c->_session_delete_reason($msg);
354 sub session_delete_reason {
357 $c->session_is_valid; # check that it was loaded
359 $c->_session_delete_reason(@_);
362 sub session_expires {
365 if ( defined( my $expires = $c->_extended_session_expires ) ) {
367 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
368 return $c->extend_session_expires( $expires );
374 sub extend_session_expires {
375 my ( $c, $expires ) = @_;
376 $c->_extended_session_expires( my $updated = $c->calculate_initial_session_expires() );
377 $c->extend_session_id( $c->sessionid, $updated );
381 sub change_session_expires {
382 my ( $c, $expires ) = @_;
385 my $sid = $c->sessionid;
386 my $time_exp = time() + $expires;
387 $c->store_session_data( "expires:$sid" => $time_exp );
390 sub _get_stored_session_expires {
393 if ( my $sid = $c->sessionid ) {
394 return $c->get_session_data("expires:$sid") || 0;
400 sub initial_session_expires {
402 return ( time() + $c->_session_plugin_config->{expires} );
405 sub calculate_initial_session_expires {
407 return max( $c->initial_session_expires, $c->_get_stored_session_expires );
410 sub calculate_extended_session_expires {
411 my ( $c, $prev ) = @_;
412 return ( time() + $prev );
415 sub reset_session_expires {
416 my ( $c, $sid ) = @_;
418 my $exp = $c->calculate_initial_session_expires;
419 $c->_session_expires( $exp );
421 # since we're setting _session_expires directly, make load_session_expires
422 # actually use that value.
424 $c->_tried_loading_session_expires(1);
425 $c->_extended_session_expires( $exp );
432 return $c->_sessionid || $c->_load_sessionid;
435 sub _load_sessionid {
437 return if $c->_tried_loading_session_id;
438 $c->_tried_loading_session_id(1);
440 if ( defined( my $sid = $c->get_session_id ) ) {
441 if ( $c->validate_session_id($sid) ) {
442 # temporarily set the inner key, so that validation will work
443 $c->_sessionid($sid);
446 my $err = "Tried to set invalid session ID '$sid'";
447 $c->log->error($err);
448 Catalyst::Exception->throw($err);
455 sub session_is_valid {
458 # force a check for expiry, but also __address, etc
459 if ( $c->_load_session ) {
466 sub validate_session_id {
467 my ( $c, $sid ) = @_;
469 $sid and $sid =~ /^[a-f\d]+$/i;
475 my $session = $c->_session || $c->_load_session || do {
476 $c->create_session_id_if_needed;
477 $c->initialize_session_data;
481 my $new_values = @_ > 1 ? { @_ } : $_[0];
482 croak('session takes a hash or hashref') unless ref $new_values;
484 for my $key (keys %$new_values) {
485 $session->{$key} = $new_values->{$key};
493 my ( $c, @keys ) = @_;
494 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
495 (@{$href}{@keys}) = ((undef) x @keys);
500 $c->_flash || $c->_load_flash || do {
501 $c->create_session_id_if_needed;
509 my $items = @_ > 1 ? {@_} : $_[0];
510 croak('flash takes a hash or hashref') unless ref $items;
511 @{ $c->_flash }{ keys %$items } = values %$items;
525 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
526 $c->_flash_key_hashes({});
527 $c->_flash_keep_keys({});
531 sub session_expire_key {
532 my ( $c, %keys ) = @_;
535 @{ $c->session->{__expire_keys} }{ keys %keys } =
536 map { $now + $_ } values %keys;
539 sub initialize_session_data {
550 $c->_session_plugin_config->{verify_address}
551 ? ( __address => $c->request->address||'' )
555 $c->_session_plugin_config->{verify_user_agent}
556 ? ( __user_agent => $c->request->user_agent||'' )
563 sub generate_session_id {
566 my $digest = $c->_find_digest();
567 $digest->add( $c->session_hash_seed() );
568 return $digest->hexdigest;
571 sub create_session_id_if_needed {
573 $c->create_session_id unless $c->sessionid;
576 sub create_session_id {
579 my $sid = $c->generate_session_id;
581 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
583 $c->_sessionid($sid);
584 $c->reset_session_expires;
585 $c->set_session_id($sid);
592 sub session_hash_seed {
595 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
600 sub _find_digest () {
602 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
603 if ( eval { Digest->new($alg) } ) {
608 Catalyst::Exception->throw(
609 "Could not find a suitable Digest module. Please install "
610 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
614 return Digest->new($usable);
621 $c->maybe::next::method(),
624 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
630 sub get_session_id { shift->maybe::next::method(@_) }
631 sub set_session_id { shift->maybe::next::method(@_) }
632 sub delete_session_id { shift->maybe::next::method(@_) }
633 sub extend_session_id { shift->maybe::next::method(@_) }
643 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
647 # To get sessions to "just work", all you need to do is use these plugins:
651 Session::Store::FastMmap
652 Session::State::Cookie
655 # you can replace Store::FastMmap with Store::File - both have sensible
656 # default configurations (see their docs for details)
658 # more complicated backends are available for other scenarios (DBI storage,
662 # after you've loaded the plugins you can save session data
663 # For example, if you are writing a shopping cart, it could be implemented
666 sub add_item : Local {
667 my ( $self, $c ) = @_;
669 my $item_id = $c->req->param("item");
671 # $c->session is a hash ref, a bit like $c->stash
672 # the difference is that it' preserved across requests
674 push @{ $c->session->{items} }, $item_id;
676 $c->forward("MyView");
679 sub display_items : Local {
680 my ( $self, $c ) = @_;
682 # values in $c->session are restored
683 $c->stash->{items_to_display} =
684 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
686 $c->forward("MyView");
691 The Session plugin is the base of two related parts of functionality required
692 for session management in web applications.
694 The first part, the State, is getting the browser to repeat back a session key,
695 so that the web application can identify the client and logically string
696 several requests together into a session.
698 The second part, the Store, deals with the actual storage of information about
699 the client. This data is stored so that the it may be revived for every request
700 made by the same client.
702 This plugin links the two pieces together.
704 =head1 RECOMENDED BACKENDS
708 =item Session::State::Cookie
710 The only really sane way to do state is using cookies.
712 =item Session::Store::File
714 A portable backend, based on Cache::File.
716 =item Session::Store::FastMmap
718 A fast and flexible backend, based on Cache::FastMmap.
728 An accessor for the session ID value.
732 Returns a hash reference that might contain unserialized values from previous
733 requests in the same session, and whose modified value will be saved for future
736 This method will automatically create a new session and session ID if none
739 You can also set session keys by passing a list of key/value pairs or a
742 $c->session->{foo} = "bar"; # This works.
743 $c->session(one => 1, two => 2); # And this.
744 $c->session({ answer => 42 }); # And this.
746 =item session_expires
748 This method returns the time when the current session will expire, or 0 if
749 there is no current session. If there is a session and it already expired, it
750 will delete the session and return 0 as well.
754 This is like Ruby on Rails' flash data structure. Think of it as a stash that
755 lasts for longer than one request, letting you redirect instead of forward.
757 The flash data will be cleaned up only on requests on which actually use
758 $c->flash (thus allowing multiple redirections), and the policy is to delete
759 all the keys which haven't changed since the flash data was loaded at the end
762 Note that use of the flash is an easy way to get data across requests, but
763 it's also strongly disrecommended, due it it being inherently plagued with
764 race conditions. This means that it's unlikely to work well if your
765 users have multiple tabs open at once, or if your site does a lot of AJAX
768 L<Catalyst::Plugin::StatusMessage> is the recommended alternative solution,
769 as this doesn't suffer from these issues.
772 my ( $self, $c ) = @_;
774 $c->flash->{beans} = 10;
775 $c->response->redirect( $c->uri_for("foo") );
779 my ( $self, $c ) = @_;
781 my $value = $c->flash->{beans};
785 $c->response->redirect( $c->uri_for("bar") );
789 my ( $self, $c ) = @_;
791 if ( exists $c->flash->{beans} ) { # false
798 Zap all the keys in the flash regardless of their current state.
800 =item keep_flash @keys
802 If you want to keep a flash key for the next request too, even if it hasn't
803 changed, call C<keep_flash> and pass in the keys as arguments.
805 =item delete_session REASON
807 This method is used to invalidate a session. It takes an optional parameter
808 which will be saved in C<session_delete_reason> if provided.
810 NOTE: This method will B<also> delete your flash data.
812 =item session_delete_reason
814 This accessor contains a string with the reason a session was deleted. Possible
829 =item session_expire_key $key, $ttl
831 Mark a key to expire at a certain time (only useful when shorter than the
832 expiry time for the whole session).
836 __PACKAGE__->config('Plugin::Session' => { expires => 10000000000 }); # "forever"
837 (NB If this number is too large, Y2K38 breakage could result.)
841 $c->session_expire_key( __user => 3600 );
843 Will make the session data survive, but the user will still be logged out after
846 Note that these values are not auto extended.
848 =item change_session_id
850 By calling this method you can force a session id change while keeping all
851 session data. This method might come handy when you are paranoid about some
852 advanced variations of session fixation attack.
854 If you want to prevent this session fixation scenario:
856 0) let us have WebApp with anonymous and authenticated parts
857 1) a hacker goes to vulnerable WebApp and gets a real sessionid,
858 just by browsing anonymous part of WebApp
859 2) the hacker inserts (somehow) this values into a cookie in victim's browser
860 3) after the victim logs into WebApp the hacker can enter his/her session
862 you should call change_session_id in your login controller like this:
864 if ($c->authenticate( { username => $user, password => $pass } )) {
866 $c->change_session_id;
873 =item change_session_expires $expires
875 You can change the session expiration time for this session;
877 $c->change_session_expires( 4000 );
879 Note that this only works to set the session longer than the config setting.
883 =head1 INTERNAL METHODS
889 This method is extended to also make calls to
890 C<check_session_plugin_requirements> and C<setup_session>.
892 =item check_session_plugin_requirements
894 This method ensures that a State and a Store plugin are also in use by the
899 This method populates C<< $c->config('Plugin::Session') >> with the default values
900 listed in L</CONFIGURATION>.
904 This method is extended.
906 Its only effect is if the (off by default) C<flash_to_stash> configuration
907 parameter is on - then it will copy the contents of the flash to the stash at
910 =item finalize_headers
912 This method is extended and will extend the expiry time before sending
917 This method is extended and will call finalize_session before the other
918 finalize_body methods run. Here we persist the session data if a session exists.
920 =item initialize_session_data
922 This method will initialize the internal structure of the session, and is
923 called by the C<session> method if appropriate.
925 =item create_session_id
927 Creates a new session ID using C<generate_session_id> if there is no session ID
930 =item validate_session_id SID
932 Make sure a session ID is of the right format.
934 This currently ensures that the session ID string is any amount of case
935 insensitive hexadecimal characters.
937 =item generate_session_id
939 This method will return a string that can be used as a session ID. It is
940 supposed to be a reasonably random string with enough bits to prevent
941 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
942 MD5 or SHA-256, depending on the availability of these modules.
944 =item session_hash_seed
946 This method is actually rather internal to generate_session_id, but should be
947 overridable in case you want to provide more random data.
949 Currently it returns a concatenated string which contains:
955 =item * The current time
957 =item * One value from C<rand>.
959 =item * The stringified value of a newly allocated hash reference
961 =item * The stringified value of the Catalyst context object
965 in the hopes that those combined values are entropic enough for most uses. If
966 this is not the case you can replace C<session_hash_seed> with e.g.
968 sub session_hash_seed {
969 open my $fh, "<", "/dev/random";
970 read $fh, my $bytes, 20;
975 Or even more directly, replace C<generate_session_id>:
977 sub generate_session_id {
978 open my $fh, "<", "/dev/random";
979 read $fh, my $bytes, 20;
981 return unpack("H*", $bytes);
984 Also have a look at L<Crypt::Random> and the various openssl bindings - these
985 modules provide APIs for cryptographically secure random data.
987 =item finalize_session
989 Clean up the session during C<finalize>.
991 This clears the various accessors after saving to the store.
995 See L<Catalyst/dump_these> - ammends the session data structure to the list of
996 dumped objects if session ID is defined.
999 =item calculate_extended_session_expires
1001 =item calculate_initial_session_expires
1003 =item create_session_id_if_needed
1005 =item delete_session_id
1007 =item extend_session_expires
1009 Note: this is *not* used to give an individual user a longer session. See
1010 'change_session_expires'.
1012 =item extend_session_id
1014 =item get_session_id
1016 =item reset_session_expires
1018 =item session_is_valid
1020 =item set_session_id
1022 =item initial_session_expires
1026 =head1 USING SESSIONS DURING PREPARE
1028 The earliest point in time at which you may use the session data is after
1029 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
1031 State plugins must set $c->session ID before C<prepare_action>, and during
1032 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
1035 sub prepare_action {
1038 # don't touch $c->session yet!
1040 $c->NEXT::prepare_action( @_ );
1042 $c->session; # this is OK
1043 $c->sessionid; # this is also OK
1046 =head1 CONFIGURATION
1048 $c->config('Plugin::Session' => {
1052 All configuation parameters are provided in a hash reference under the
1053 C<Plugin::Session> key in the configuration hash.
1059 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
1062 =item expiry_threshold
1064 The time (in seconds) before the session expiration to update the
1065 expiration time (and thus the session).
1067 The purpose of this is to keep the session store from being updated
1068 when nothing else in the session is updated.
1070 Defaults to 0 (in which case, the expiration will always be updated).
1072 =item verify_address
1074 When true, C<< $c->request->address >> will be checked at prepare time. If it is
1075 not the same as the address that initiated the session, the session is deleted.
1079 =item verify_user_agent
1081 When true, C<< $c->request->user_agent >> will be checked at prepare time. If it
1082 is not the same as the user agent that initiated the session, the session is
1087 =item flash_to_stash
1089 This option makes it easier to have actions behave the same whether they were
1090 forwarded to or redirected to. On prepare time it copies the contents of
1091 C<flash> (if any) to the stash.
1097 The hash reference returned by C<< $c->session >> contains several keys which
1098 are automatically set:
1104 This key no longer exists. Use C<session_expires> instead.
1108 The last time a session was saved to the store.
1112 The time when the session was first created.
1116 The value of C<< $c->request->address >> at the time the session was created.
1117 This value is only populated if C<verify_address> is true in the configuration.
1121 The value of C<< $c->request->user_agent >> at the time the session was created.
1122 This value is only populated if C<verify_user_agent> is true in the configuration.
1128 =head2 Round the Robin Proxies
1130 C<verify_address> could make your site inaccessible to users who are behind
1131 load balanced proxies. Some ISPs may give a different IP to each request by the
1132 same client due to this type of proxying. If addresses are verified these
1133 users' sessions cannot persist.
1135 To let these users access your site you can either disable address verification
1136 as a whole, or provide a checkbox in the login dialog that tells the server
1137 that it's OK for the address of the client to change. When the server sees that
1138 this box is checked it should delete the C<__address> special key from the
1139 session hash when the hash is first created.
1141 =head2 Race Conditions
1143 In this day and age where cleaning detergents and Dutch football (not the
1144 American kind) teams roam the plains in great numbers, requests may happen
1145 simultaneously. This means that there is some risk of session data being
1146 overwritten, like this:
1152 request a starts, request b starts, with the same session ID
1156 session data is loaded in request a
1160 session data is loaded in request b
1164 session data is changed in request a
1168 request a finishes, session data is updated and written to store
1172 request b finishes, session data is updated and written to store, overwriting
1173 changes by request a
1177 For applications where any given user's session is only making one request
1178 at a time this plugin should be safe enough.
1186 Yuval Kogman, C<nothingmuch@woobling.org>
1190 Tomas Doran (t0m) C<bobtfish@bobtfish.net> (current maintainer)
1196 Florian Ragwitz (rafl) C<rafl@debian.org>
1198 Kent Fredric (kentnl)
1200 And countless other contributers from #catalyst. Thanks guys!
1204 Devin Austin (dhoss) <dhoss@cpan.org>
1206 =head1 COPYRIGHT & LICENSE
1208 Copyright (c) 2005 the aforementioned authors. All rights
1209 reserved. This program is free software; you can redistribute
1210 it and/or modify it under the same terms as Perl itself.