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 = '0.37';
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,
83 expiry_threshold => 0,
87 $c->maybe::next::method();
93 $c->maybe::next::method(@_);
95 if ( $c->_session_plugin_config->{flash_to_stash}
97 and my $flash_data = $c->flash )
99 @{ $c->stash }{ keys %$flash_data } = values %$flash_data;
103 sub finalize_headers {
106 # fix cookie before we send headers
107 $c->_save_session_expires;
109 # Force extension of session_expires before finalizing headers, so a pos
110 # up to date. First call to session_expires will extend the expiry, subs
111 # just return the previously extended value.
114 return $c->maybe::next::method(@_);
120 # We have to finalize our session *before* $c->engine->finalize_xxx is called,
121 # because we do not want to send the HTTP response before the session is stored/committed to
122 # the session database (or whatever Session::Store you use).
123 $c->finalize_session;
125 return $c->maybe::next::method(@_);
128 sub finalize_session {
131 $c->maybe::next::method(@_);
133 $c->_save_session_id;
137 $c->_clear_session_instance_data;
140 sub _save_session_id {
143 # we already called set when allocating
144 # no need to tell the state plugins anything new
147 sub _save_session_expires {
150 if ( defined($c->_session_expires) ) {
152 my $threshold = $c->_session_plugin_config->{expiry_threshold} || 0;
154 if ( my $sid = $c->sessionid ) {
155 my $cutoff = ( $c->get_session_data("expires:$sid") || 0 ) - $threshold;
157 if (!$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 = $c->get_session_data("expires:$sid") || 0;
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( $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 initial_session_expires {
392 return ( time() + $c->_session_plugin_config->{expires} );
395 sub calculate_initial_session_expires {
398 my $initial_expires = $c->initial_session_expires;
399 my $stored_session_expires = 0;
400 if ( my $sid = $c->sessionid ) {
401 $stored_session_expires = $c->get_session_data("expires:$sid") || 0;
403 return ( $initial_expires > $stored_session_expires ) ? $initial_expires : $stored_session_expires;
406 sub calculate_extended_session_expires {
407 my ( $c, $prev ) = @_;
408 return ( time() + $prev );
411 sub reset_session_expires {
412 my ( $c, $sid ) = @_;
414 my $exp = $c->calculate_initial_session_expires;
415 $c->_session_expires( $exp );
417 # since we're setting _session_expires directly, make load_session_expires
418 # actually use that value.
420 $c->_tried_loading_session_expires(1);
421 $c->_extended_session_expires( $exp );
428 return $c->_sessionid || $c->_load_sessionid;
431 sub _load_sessionid {
433 return if $c->_tried_loading_session_id;
434 $c->_tried_loading_session_id(1);
436 if ( defined( my $sid = $c->get_session_id ) ) {
437 if ( $c->validate_session_id($sid) ) {
438 # temporarily set the inner key, so that validation will work
439 $c->_sessionid($sid);
442 my $err = "Tried to set invalid session ID '$sid'";
443 $c->log->error($err);
444 Catalyst::Exception->throw($err);
451 sub session_is_valid {
454 # force a check for expiry, but also __address, etc
455 if ( $c->_load_session ) {
462 sub validate_session_id {
463 my ( $c, $sid ) = @_;
465 $sid and $sid =~ /^[a-f\d]+$/i;
471 my $session = $c->_session || $c->_load_session || do {
472 $c->create_session_id_if_needed;
473 $c->initialize_session_data;
477 my $new_values = @_ > 1 ? { @_ } : $_[0];
478 croak('session takes a hash or hashref') unless ref $new_values;
480 for my $key (keys %$new_values) {
481 $session->{$key} = $new_values->{$key};
489 my ( $c, @keys ) = @_;
490 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
491 (@{$href}{@keys}) = ((undef) x @keys);
496 $c->_flash || $c->_load_flash || do {
497 $c->create_session_id_if_needed;
505 my $items = @_ > 1 ? {@_} : $_[0];
506 croak('flash takes a hash or hashref') unless ref $items;
507 @{ $c->_flash }{ keys %$items } = values %$items;
521 #$c->delete_session_data("flash:" . $c->sessionid); # should this be in here? or delayed till finalization?
522 $c->_flash_key_hashes({});
523 $c->_flash_keep_keys({});
527 sub session_expire_key {
528 my ( $c, %keys ) = @_;
531 @{ $c->session->{__expire_keys} }{ keys %keys } =
532 map { $now + $_ } values %keys;
535 sub initialize_session_data {
546 $c->_session_plugin_config->{verify_address}
547 ? ( __address => $c->request->address||'' )
551 $c->_session_plugin_config->{verify_user_agent}
552 ? ( __user_agent => $c->request->user_agent||'' )
559 sub generate_session_id {
562 my $digest = $c->_find_digest();
563 $digest->add( $c->session_hash_seed() );
564 return $digest->hexdigest;
567 sub create_session_id_if_needed {
569 $c->create_session_id unless $c->sessionid;
572 sub create_session_id {
575 my $sid = $c->generate_session_id;
577 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
579 $c->_sessionid($sid);
580 $c->reset_session_expires;
581 $c->set_session_id($sid);
588 sub session_hash_seed {
591 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
596 sub _find_digest () {
598 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
599 if ( eval { Digest->new($alg) } ) {
604 Catalyst::Exception->throw(
605 "Could not find a suitable Digest module. Please install "
606 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
610 return Digest->new($usable);
617 $c->maybe::next::method(),
620 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
626 sub get_session_id { shift->maybe::next::method(@_) }
627 sub set_session_id { shift->maybe::next::method(@_) }
628 sub delete_session_id { shift->maybe::next::method(@_) }
629 sub extend_session_id { shift->maybe::next::method(@_) }
639 Catalyst::Plugin::Session - Generic Session plugin - ties together server side storage and client side state required to maintain session data.
643 # To get sessions to "just work", all you need to do is use these plugins:
647 Session::Store::FastMmap
648 Session::State::Cookie
651 # you can replace Store::FastMmap with Store::File - both have sensible
652 # default configurations (see their docs for details)
654 # more complicated backends are available for other scenarios (DBI storage,
658 # after you've loaded the plugins you can save session data
659 # For example, if you are writing a shopping cart, it could be implemented
662 sub add_item : Local {
663 my ( $self, $c ) = @_;
665 my $item_id = $c->req->param("item");
667 # $c->session is a hash ref, a bit like $c->stash
668 # the difference is that it' preserved across requests
670 push @{ $c->session->{items} }, $item_id;
672 $c->forward("MyView");
675 sub display_items : Local {
676 my ( $self, $c ) = @_;
678 # values in $c->session are restored
679 $c->stash->{items_to_display} =
680 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
682 $c->forward("MyView");
687 The Session plugin is the base of two related parts of functionality required
688 for session management in web applications.
690 The first part, the State, is getting the browser to repeat back a session key,
691 so that the web application can identify the client and logically string
692 several requests together into a session.
694 The second part, the Store, deals with the actual storage of information about
695 the client. This data is stored so that the it may be revived for every request
696 made by the same client.
698 This plugin links the two pieces together.
700 =head1 RECOMENDED BACKENDS
704 =item Session::State::Cookie
706 The only really sane way to do state is using cookies.
708 =item Session::Store::File
710 A portable backend, based on Cache::File.
712 =item Session::Store::FastMmap
714 A fast and flexible backend, based on Cache::FastMmap.
724 An accessor for the session ID value.
728 Returns a hash reference that might contain unserialized values from previous
729 requests in the same session, and whose modified value will be saved for future
732 This method will automatically create a new session and session ID if none
735 You can also set session keys by passing a list of key/value pairs or a
738 $c->session->{foo} = "bar"; # This works.
739 $c->session(one => 1, two => 2); # And this.
740 $c->session({ answer => 42 }); # And this.
742 =item session_expires
744 This method returns the time when the current session will expire, or 0 if
745 there is no current session. If there is a session and it already expired, it
746 will delete the session and return 0 as well.
750 This is like Ruby on Rails' flash data structure. Think of it as a stash that
751 lasts for longer than one request, letting you redirect instead of forward.
753 The flash data will be cleaned up only on requests on which actually use
754 $c->flash (thus allowing multiple redirections), and the policy is to delete
755 all the keys which haven't changed since the flash data was loaded at the end
758 Note that use of the flash is an easy way to get data across requests, but
759 it's also strongly disrecommended, due it it being inherently plagued with
760 race conditions. This means that it's unlikely to work well if your
761 users have multiple tabs open at once, or if your site does a lot of AJAX
764 L<Catalyst::Plugin::StatusMessage> is the recommended alternative solution,
765 as this doesn't suffer from these issues.
768 my ( $self, $c ) = @_;
770 $c->flash->{beans} = 10;
771 $c->response->redirect( $c->uri_for("foo") );
775 my ( $self, $c ) = @_;
777 my $value = $c->flash->{beans};
781 $c->response->redirect( $c->uri_for("bar") );
785 my ( $self, $c ) = @_;
787 if ( exists $c->flash->{beans} ) { # false
794 Zap all the keys in the flash regardless of their current state.
796 =item keep_flash @keys
798 If you want to keep a flash key for the next request too, even if it hasn't
799 changed, call C<keep_flash> and pass in the keys as arguments.
801 =item delete_session REASON
803 This method is used to invalidate a session. It takes an optional parameter
804 which will be saved in C<session_delete_reason> if provided.
806 NOTE: This method will B<also> delete your flash data.
808 =item session_delete_reason
810 This accessor contains a string with the reason a session was deleted. Possible
825 =item session_expire_key $key, $ttl
827 Mark a key to expire at a certain time (only useful when shorter than the
828 expiry time for the whole session).
832 __PACKAGE__->config('Plugin::Session' => { expires => 10000000000 }); # "forever"
833 (NB If this number is too large, Y2K38 breakage could result.)
837 $c->session_expire_key( __user => 3600 );
839 Will make the session data survive, but the user will still be logged out after
842 Note that these values are not auto extended.
844 =item change_session_id
846 By calling this method you can force a session id change while keeping all
847 session data. This method might come handy when you are paranoid about some
848 advanced variations of session fixation attack.
850 If you want to prevent this session fixation scenario:
852 0) let us have WebApp with anonymous and authenticated parts
853 1) a hacker goes to vulnerable WebApp and gets a real sessionid,
854 just by browsing anonymous part of WebApp
855 2) the hacker inserts (somehow) this values into a cookie in victim's browser
856 3) after the victim logs into WebApp the hacker can enter his/her session
858 you should call change_session_id in your login controller like this:
860 if ($c->authenticate( { username => $user, password => $pass } )) {
862 $c->change_session_id;
869 =item change_session_expires $expires
871 You can change the session expiration time for this session;
873 $c->change_session_expires( 4000 );
875 Note that this only works to set the session longer than the config setting.
879 =head1 INTERNAL METHODS
885 This method is extended to also make calls to
886 C<check_session_plugin_requirements> and C<setup_session>.
888 =item check_session_plugin_requirements
890 This method ensures that a State and a Store plugin are also in use by the
895 This method populates C<< $c->config('Plugin::Session') >> with the default values
896 listed in L</CONFIGURATION>.
900 This method is extended.
902 Its only effect is if the (off by default) C<flash_to_stash> configuration
903 parameter is on - then it will copy the contents of the flash to the stash at
906 =item finalize_headers
908 This method is extended and will extend the expiry time before sending
913 This method is extended and will call finalize_session before the other
914 finalize_body methods run. Here we persist the session data if a session exists.
916 =item initialize_session_data
918 This method will initialize the internal structure of the session, and is
919 called by the C<session> method if appropriate.
921 =item create_session_id
923 Creates a new session ID using C<generate_session_id> if there is no session ID
926 =item validate_session_id SID
928 Make sure a session ID is of the right format.
930 This currently ensures that the session ID string is any amount of case
931 insensitive hexadecimal characters.
933 =item generate_session_id
935 This method will return a string that can be used as a session ID. It is
936 supposed to be a reasonably random string with enough bits to prevent
937 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
938 MD5 or SHA-256, depending on the availability of these modules.
940 =item session_hash_seed
942 This method is actually rather internal to generate_session_id, but should be
943 overridable in case you want to provide more random data.
945 Currently it returns a concatenated string which contains:
951 =item * The current time
953 =item * One value from C<rand>.
955 =item * The stringified value of a newly allocated hash reference
957 =item * The stringified value of the Catalyst context object
961 in the hopes that those combined values are entropic enough for most uses. If
962 this is not the case you can replace C<session_hash_seed> with e.g.
964 sub session_hash_seed {
965 open my $fh, "<", "/dev/random";
966 read $fh, my $bytes, 20;
971 Or even more directly, replace C<generate_session_id>:
973 sub generate_session_id {
974 open my $fh, "<", "/dev/random";
975 read $fh, my $bytes, 20;
977 return unpack("H*", $bytes);
980 Also have a look at L<Crypt::Random> and the various openssl bindings - these
981 modules provide APIs for cryptographically secure random data.
983 =item finalize_session
985 Clean up the session during C<finalize>.
987 This clears the various accessors after saving to the store.
991 See L<Catalyst/dump_these> - ammends the session data structure to the list of
992 dumped objects if session ID is defined.
995 =item calculate_extended_session_expires
997 =item calculate_initial_session_expires
999 =item create_session_id_if_needed
1001 =item delete_session_id
1003 =item extend_session_expires
1005 Note: this is *not* used to give an individual user a longer session. See
1006 'change_session_expires'.
1008 =item extend_session_id
1010 =item get_session_id
1012 =item reset_session_expires
1014 =item session_is_valid
1016 =item set_session_id
1018 =item initial_session_expires
1022 =head1 USING SESSIONS DURING PREPARE
1024 The earliest point in time at which you may use the session data is after
1025 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
1027 State plugins must set $c->session ID before C<prepare_action>, and during
1028 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
1031 sub prepare_action {
1034 # don't touch $c->session yet!
1036 $c->NEXT::prepare_action( @_ );
1038 $c->session; # this is OK
1039 $c->sessionid; # this is also OK
1042 =head1 CONFIGURATION
1044 $c->config('Plugin::Session' => {
1048 All configuation parameters are provided in a hash reference under the
1049 C<Plugin::Session> key in the configuration hash.
1055 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
1058 =item expiry_threshold
1060 The time (in seconds) before the session expiration to update the
1061 expiration time (and thus the session).
1063 The purpose of this is to keep the session store from being updated
1064 when nothing else in the session is updated.
1066 Defaults to 0 (in which case, the expiration will always be updated).
1068 =item verify_address
1070 When true, C<< $c->request->address >> will be checked at prepare time. If it is
1071 not the same as the address that initiated the session, the session is deleted.
1075 =item verify_user_agent
1077 When true, C<< $c->request->user_agent >> will be checked at prepare time. If it
1078 is not the same as the user agent that initiated the session, the session is
1083 =item flash_to_stash
1085 This option makes it easier to have actions behave the same whether they were
1086 forwarded to or redirected to. On prepare time it copies the contents of
1087 C<flash> (if any) to the stash.
1093 The hash reference returned by C<< $c->session >> contains several keys which
1094 are automatically set:
1100 This key no longer exists. Use C<session_expires> instead.
1104 The last time a session was saved to the store.
1108 The time when the session was first created.
1112 The value of C<< $c->request->address >> at the time the session was created.
1113 This value is only populated if C<verify_address> is true in the configuration.
1117 The value of C<< $c->request->user_agent >> at the time the session was created.
1118 This value is only populated if C<verify_user_agent> is true in the configuration.
1124 =head2 Round the Robin Proxies
1126 C<verify_address> could make your site inaccessible to users who are behind
1127 load balanced proxies. Some ISPs may give a different IP to each request by the
1128 same client due to this type of proxying. If addresses are verified these
1129 users' sessions cannot persist.
1131 To let these users access your site you can either disable address verification
1132 as a whole, or provide a checkbox in the login dialog that tells the server
1133 that it's OK for the address of the client to change. When the server sees that
1134 this box is checked it should delete the C<__address> special key from the
1135 session hash when the hash is first created.
1137 =head2 Race Conditions
1139 In this day and age where cleaning detergents and Dutch football (not the
1140 American kind) teams roam the plains in great numbers, requests may happen
1141 simultaneously. This means that there is some risk of session data being
1142 overwritten, like this:
1148 request a starts, request b starts, with the same session ID
1152 session data is loaded in request a
1156 session data is loaded in request b
1160 session data is changed in request a
1164 request a finishes, session data is updated and written to store
1168 request b finishes, session data is updated and written to store, overwriting
1169 changes by request a
1173 For applications where any given user's session is only making one request
1174 at a time this plugin should be safe enough.
1182 Yuval Kogman, C<nothingmuch@woobling.org>
1186 Tomas Doran (t0m) C<bobtfish@bobtfish.net> (current maintainer)
1192 Florian Ragwitz (rafl) C<rafl@debian.org>
1194 Kent Fredric (kentnl)
1196 And countless other contributers from #catalyst. Thanks guys!
1200 Devin Austin (dhoss) <dhoss@cpan.org>
1202 =head1 COPYRIGHT & LICENSE
1204 Copyright (c) 2005 the aforementioned authors. All rights
1205 reserved. This program is free software; you can redistribute
1206 it and/or modify it under the same terms as Perl itself.