3 package Catalyst::Plugin::Session;
4 use base qw/Class::Accessor::Fast/;
10 use Catalyst::Exception ();
13 use Object::Signature ();
15 our $VERSION = "0.09";
17 my @session_data_accessors; # used in delete_session
19 __PACKAGE__->mk_accessors(
20 "_session_delete_reason",
21 @session_data_accessors = qw/
29 _tried_loading_session_id
30 _tried_loading_session_data
31 _tried_loading_session_expires
32 _tried_loading_flash_data
42 $c->check_session_plugin_requirements;
48 sub check_session_plugin_requirements {
51 unless ( $c->isa("Catalyst::Plugin::Session::State")
52 && $c->isa("Catalyst::Plugin::Session::Store") )
55 ( "The Session plugin requires both Session::State "
56 . "and Session::Store plugins to be used as well." );
59 Catalyst::Exception->throw($err);
66 my $cfg = ( $c->config->{session} ||= {} );
74 $c->NEXT::setup_session();
80 if ( $c->config->{session}{flash_to_stash}
82 and my $flash_data = $c->flash )
84 @{ $c->stash }{ keys %$flash_data } = values %$flash_data;
87 $c->NEXT::prepare_action(@_);
93 $c->_save_session_expires;
98 $c->NEXT::finalize(@_);
101 sub _save_session_id {
105 sub _save_session_expires {
108 if ( defined(my $expires = $c->_session_expires) ) {
109 my $sid = $c->sessionid;
110 $c->store_session_data( "expires:$sid" => $expires );
112 $c->_session_expires(undef);
113 $c->_tried_loading_session_expires(undef);
120 if ( my $session_data = $c->_session ) {
122 no warnings 'uninitialized';
123 if ( Object::Signature::signature($session_data) ne
124 $c->_session_data_sig )
126 $session_data->{__updated} = time();
127 my $sid = $c->sessionid;
128 $c->store_session_data( "session:$sid" => $session_data );
132 $c->_tried_loading_session_data(undef);
139 if ( my $flash_data = $c->_flash ) {
141 my $hashes = $c->_flash_key_hashes || {};
142 my $keep = $c->_flash_keep_keys || {};
143 foreach my $key ( keys %$hashes ) {
144 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
145 delete $flash_data->{$key};
149 my $sid = $c->sessionid;
152 $c->store_session_data( "flash:$sid", $flash_data );
155 $c->delete_session_data("flash:$sid");
159 $c->_tried_loading_flash_data(undef);
163 sub _load_session_expires {
165 return $c->_session_expires if $c->_tried_loading_session_expires;
166 $c->_tried_loading_session_expires(1);
168 if ( my $sid = $c->sessionid ) {
169 my $expires = $c->get_session_data("expires:$sid") || 0;
171 if ( $expires >= time() ) {
172 return $c->extend_session_expires( $expires );
174 $c->delete_session( "session expired" );
184 return $c->_session if $c->_tried_loading_session_data;
185 $c->_tried_loading_session_data(1);
187 if ( my $sid = $c->sessionid ) {
188 if ( $c->session_expires ) { # > 0
190 my $session_data = $c->get_session_data("session:$sid") || return;
191 $c->_session($session_data);
193 no warnings 'uninitialized'; # ne __address
194 if ( $c->config->{session}{verify_address}
195 && $session_data->{__address} ne $c->request->address )
198 "Deleting session $sid due to address mismatch ("
199 . $session_data->{__address} . " != "
200 . $c->request->address . ")"
202 $c->delete_session("address mismatch");
206 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
207 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
208 $c->_expire_session_keys;
210 return $session_data;
219 return $c->_flash if $c->_tried_loading_flash_data;
220 $c->_tried_loading_flash_data(1);
222 if ( my $sid = $c->sessionid ) {
223 if ( my $flash_data = $c->_flash
224 || $c->_flash( $c->get_session_data("flash:$sid") ) )
226 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
235 sub _expire_session_keys {
236 my ( $c, $data ) = @_;
240 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
241 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
242 delete $c->_session->{$key};
243 delete $expire_times->{$key};
248 my ( $c, $msg ) = @_;
250 $c->log->debug("Deleting session") if $c->debug;
252 # delete the session data
253 if ( my $sid = $c->sessionid ) {
254 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
255 $c->delete_session_id($sid);
258 # reset the values in the context object
259 # see the BEGIN block
260 $c->$_(undef) for @session_data_accessors;
262 $c->_session_delete_reason($msg);
265 sub session_delete_reason {
268 $c->session_is_valid; # check that it was loaded
270 $c->_session_delete_reason(@_);
273 sub session_expires {
276 if ( defined( my $expires = $c->_session_expires ) ) {
278 } elsif ( defined( $expires = $c->_load_session_expires ) ) {
279 $c->_session_expires($expires);
286 sub extend_session_expires {
287 my ( $c, $expires ) = @_;
288 $c->_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
289 $c->extend_session_id( $c->sessionid, $updated );
293 sub calculate_initial_session_expires {
295 return ( time() + $c->config->{session}{expires} );
298 sub calculate_extended_session_expires {
299 my ( $c, $prev ) = @_;
300 $c->calculate_initial_session_expires;
303 sub reset_session_expires {
304 my ( $c, $sid ) = @_;
305 $c->_session_expires( my $exp = $c->calculate_initial_session_expires );
312 return $c->_sessionid || $c->_load_sessionid;
315 sub _load_sessionid {
317 return if $c->_tried_loading_session_id;
318 $c->_tried_loading_session_id(1);
320 if ( defined( my $sid = $c->get_session_id ) ) {
321 if ( $c->validate_session_id($sid) ) {
322 # temporarily set the inner key, so that validation will work
323 $c->_sessionid($sid);
326 my $err = "Tried to set invalid session ID '$sid'";
327 $c->log->error($err);
328 Catalyst::Exception->throw($err);
335 sub session_is_valid {
338 # force a check for expiry, but also __address, etc
339 if ( $c->_load_session ) {
346 sub validate_session_id {
347 my ( $c, $sid ) = @_;
349 $sid and $sid =~ /^[a-f\d]+$/i;
355 $c->_session || $c->_load_session || do {
356 $c->create_session_id_if_needed;
357 $c->initialize_session_data;
362 my ( $c, @keys ) = @_;
363 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
364 (@{$href}{@keys}) = ((undef) x @keys);
369 $c->_flash || $c->_load_flash || do {
370 $c->create_session_id_if_needed;
375 sub session_expire_key {
376 my ( $c, %keys ) = @_;
379 @{ $c->session->{__expire_keys} }{ keys %keys } =
380 map { $now + $_ } values %keys;
383 sub initialize_session_data {
394 $c->config->{session}{verify_address}
395 ? ( __address => $c->request->address )
402 sub generate_session_id {
405 my $digest = $c->_find_digest();
406 $digest->add( $c->session_hash_seed() );
407 return $digest->hexdigest;
410 sub create_session_id_if_needed {
412 $c->create_session_id unless $c->sessionid;
415 sub create_session_id {
418 my $sid = $c->generate_session_id;
420 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
422 $c->_sessionid($sid);
423 $c->reset_session_expires;
424 $c->set_session_id($sid);
431 sub session_hash_seed {
434 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
439 sub _find_digest () {
441 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
442 if ( eval { Digest->new($alg) } ) {
447 Catalyst::Exception->throw(
448 "Could not find a suitable Digest module. Please install "
449 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
453 return Digest->new($usable);
460 $c->NEXT::dump_these(),
463 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
469 sub get_session_id { shift->NEXT::get_session_id(@_) }
470 sub set_session_id { shift->NEXT::set_session_id(@_) }
471 sub delete_session_id { shift->NEXT::delete_session_id(@_) }
472 sub extend_session_id { shift->NEXT::extend_session_id(@_) }
482 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
483 storage and client side state required to maintain session data.
487 # To get sessions to "just work", all you need to do is use these plugins:
491 Session::Store::FastMmap
492 Session::State::Cookie
495 # you can replace Store::FastMmap with Store::File - both have sensible
496 # default configurations (see their docs for details)
498 # more complicated backends are available for other scenarios (DBI storage,
502 # after you've loaded the plugins you can save session data
503 # For example, if you are writing a shopping cart, it could be implemented
506 sub add_item : Local {
507 my ( $self, $c ) = @_;
509 my $item_id = $c->req->param("item");
511 # $c->session is a hash ref, a bit like $c->stash
512 # the difference is that it' preserved across requests
514 push @{ $c->session->{items} }, $item_id;
516 $c->forward("MyView");
519 sub display_items : Local {
520 my ( $self, $c ) = @_;
522 # values in $c->session are restored
523 $c->stash->{items_to_display} =
524 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
526 $c->forward("MyView");
531 The Session plugin is the base of two related parts of functionality required
532 for session management in web applications.
534 The first part, the State, is getting the browser to repeat back a session key,
535 so that the web application can identify the client and logically string
536 several requests together into a session.
538 The second part, the Store, deals with the actual storage of information about
539 the client. This data is stored so that the it may be revived for every request
540 made by the same client.
542 This plugin links the two pieces together.
544 =head1 RECCOMENDED BACKENDS
548 =item Session::State::Cookie
550 The only really sane way to do state is using cookies.
552 =item Session::Store::File
554 A portable backend, based on Cache::File.
556 =item Session::Store::FastMmap
558 A fast and flexible backend, based on Cache::FastMmap.
568 An accessor for the session ID value.
572 Returns a hash reference that might contain unserialized values from previous
573 requests in the same session, and whose modified value will be saved for future
576 This method will automatically create a new session and session ID if none
579 =item session_expires
581 =item session_expires $reset
583 This method returns the time when the current session will expire, or 0 if
584 there is no current session. If there is a session and it already expired, it
585 will delete the session and return 0 as well.
587 If the C<$reset> parameter is true, and there is a session ID the expiry time
588 will be reset to the current time plus the time to live (see
589 L</CONFIGURATION>). This is used when creating a new session.
593 This is like Ruby on Rails' flash data structure. Think of it as a stash that
594 lasts for longer than one request, letting you redirect instead of forward.
596 The flash data will be cleaned up only on requests on which actually use
597 $c->flash (thus allowing multiple redirections), and the policy is to delete
598 all the keys which haven't changed since the flash data was loaded at the end
602 my ( $self, $c ) = @_;
604 $c->flash->{beans} = 10;
605 $c->response->redirect( $c->uri_for("foo") );
609 my ( $self, $c ) = @_;
611 my $value = $c->flash->{beans};
615 $c->response->redirect( $c->uri_for("bar") );
619 my ( $self, $c ) = @_;
621 if ( exists $c->flash->{beans} ) { # false
626 =item keep_flash @keys
628 If you wawnt to keep a flash key for the next request too, even if it hasn't
629 changed, call C<keep_flash> and pass in the keys as arguments.
631 =item delete_session REASON
633 This method is used to invalidate a session. It takes an optional parameter
634 which will be saved in C<session_delete_reason> if provided.
636 =item session_delete_reason
638 This accessor contains a string with the reason a session was deleted. Possible
653 =item session_expire_key $key, $ttl
655 Mark a key to expire at a certain time (only useful when shorter than the
656 expiry time for the whole session).
660 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
664 $c->session_expire_key( __user => 3600 );
666 Will make the session data survive, but the user will still be logged out after
669 Note that these values are not auto extended.
673 =head1 INTERNAL METHODS
679 This method is extended to also make calls to
680 C<check_session_plugin_requirements> and C<setup_session>.
682 =item check_session_plugin_requirements
684 This method ensures that a State and a Store plugin are also in use by the
689 This method populates C<< $c->config->{session} >> with the default values
690 listed in L</CONFIGURATION>.
694 This methoid is extended.
696 It's only effect is if the (off by default) C<flash_to_stash> configuration
697 parameter is on - then it will copy the contents of the flash to the stash at
702 This method is extended and will extend the expiry time, as well as persist the
703 session data if a session exists.
705 =item initialize_session_data
707 This method will initialize the internal structure of the session, and is
708 called by the C<session> method if appropriate.
710 =item create_session_id
712 Creates a new session id using C<generate_session_id> if there is no session ID
715 =item validate_session_id SID
717 Make sure a session ID is of the right format.
719 This currently ensures that the session ID string is any amount of case
720 insensitive hexadecimal characters.
722 =item generate_session_id
724 This method will return a string that can be used as a session ID. It is
725 supposed to be a reasonably random string with enough bits to prevent
726 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
727 MD5 or SHA-256, depending on the availibility of these modules.
729 =item session_hash_seed
731 This method is actually rather internal to generate_session_id, but should be
732 overridable in case you want to provide more random data.
734 Currently it returns a concatenated string which contains:
748 One value from C<rand>.
752 The stringified value of a newly allocated hash reference
756 The stringified value of the Catalyst context object
760 In the hopes that those combined values are entropic enough for most uses. If
761 this is not the case you can replace C<session_hash_seed> with e.g.
763 sub session_hash_seed {
764 open my $fh, "<", "/dev/random";
765 read $fh, my $bytes, 20;
770 Or even more directly, replace C<generate_session_id>:
772 sub generate_session_id {
773 open my $fh, "<", "/dev/random";
774 read $fh, my $bytes, 20;
776 return unpack("H*", $bytes);
779 Also have a look at L<Crypt::Random> and the various openssl bindings - these
780 modules provide APIs for cryptographically secure random data.
784 See L<Catalyst/dump_these> - ammends the session data structure to the list of
785 dumped objects if session ID is defined.
789 =head1 USING SESSIONS DURING PREPARE
791 The earliest point in time at which you may use the session data is after
792 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
794 State plugins must set $c->session ID before C<prepare_action>, and during
795 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
801 # don't touch $c->session yet!
803 $c->NEXT::prepare_action( @_ );
805 $c->session; # this is OK
806 $c->sessionid; # this is also OK
811 $c->config->{session} = {
815 All configuation parameters are provided in a hash reference under the
816 C<session> key in the configuration hash.
822 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
827 When true, C<<$c->request->address>> will be checked at prepare time. If it is
828 not the same as the address that initiated the session, the session is deleted.
832 This option makes it easier to have actions behave the same whether they were
833 forwarded to or redirected to. On prepare time it copies the contents of
834 C<flash> (if any) to the stash.
840 The hash reference returned by C<< $c->session >> contains several keys which
841 are automatically set:
847 This key no longer exists. Use C<session_expires> instead.
851 The last time a session was saved to the store.
855 The time when the session was first created.
859 The value of C<< $c->request->address >> at the time the session was created.
860 This value is only populated if C<verify_address> is true in the configuration.
866 =head2 Round the Robin Proxies
868 C<verify_address> could make your site inaccessible to users who are behind
869 load balanced proxies. Some ISPs may give a different IP to each request by the
870 same client due to this type of proxying. If addresses are verified these
871 users' sessions cannot persist.
873 To let these users access your site you can either disable address verification
874 as a whole, or provide a checkbox in the login dialog that tells the server
875 that it's OK for the address of the client to change. When the server sees that
876 this box is checked it should delete the C<__address> sepcial key from the
877 session hash when the hash is first created.
879 =head2 Race Conditions
881 In this day and age where cleaning detergents and dutch football (not the
882 american kind) teams roam the plains in great numbers, requests may happen
883 simultaneously. This means that there is some risk of session data being
884 overwritten, like this:
890 request a starts, request b starts, with the same session id
894 session data is loaded in request a
898 session data is loaded in request b
902 session data is changed in request a
906 request a finishes, session data is updated and written to store
910 request b finishes, session data is updated and written to store, overwriting
915 If this is a concern in your application, a soon to be developed locking
916 solution is the only safe way to go. This will have a bigger overhead.
918 For applications where any given user is only making one request at a time this
919 plugin should be safe enough.
927 =item Christian Hansen
929 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
931 =item Sebastian Riedel
935 And countless other contributers from #catalyst. Thanks guys!
937 =head1 COPYRIGHT & LICENSE
939 Copyright (c) 2005 the aforementioned authors. All rights
940 reserved. This program is free software; you can redistribute
941 it and/or modify it under the same terms as Perl itself.