3 package Catalyst::Plugin::Session;
4 use base qw/Class::Accessor::Fast/;
10 use Catalyst::Exception ();
13 use Object::Signature ();
15 our $VERSION = "0.05";
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
39 $c->check_session_plugin_requirements;
45 sub check_session_plugin_requirements {
48 unless ( $c->isa("Catalyst::Plugin::Session::State")
49 && $c->isa("Catalyst::Plugin::Session::Store") )
52 ( "The Session plugin requires both Session::State "
53 . "and Session::Store plugins to be used as well." );
56 Catalyst::Exception->throw($err);
63 my $cfg = ( $c->config->{session} ||= {} );
71 $c->NEXT::setup_session();
77 if ( $c->config->{session}{flash_to_stash}
79 and my $flash_data = $c->flash )
81 @{ $c->stash }{ keys %$flash_data } = values %$flash_data;
84 $c->NEXT::prepare_action(@_);
93 $c->NEXT::finalize(@_);
99 if ( my $sid = $c->sessionid ) {
101 # all sessions are extended at the end of the request
104 if ( my $expires = $c->session_expires ) {
105 $c->store_session_data( "expires:$sid" => $expires );
108 if ( my $session_data = $c->_session ) {
110 no warnings 'uninitialized';
111 if ( Object::Signature::signature($session_data) ne
112 $c->_session_data_sig )
114 $session_data->{__updated} = $now;
115 $c->store_session_data( "session:$sid" => $session_data );
124 if ( my $sid = $c->sessionid ) {
125 if ( my $flash_data = $c->_flash ) {
127 my $hashes = $c->_flash_key_hashes || {};
128 my $keep = $c->_flash_keep_keys || {};
129 foreach my $key ( keys %$hashes ) {
130 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
131 delete $flash_data->{$key};
136 $c->store_session_data( "flash:$sid", $flash_data );
139 $c->delete_session_data("flash:$sid");
145 sub _load_session_expires {
148 if ( my $sid = $c->sessionid ) {
149 my $expires = $c->get_session_data("expires:$sid") || 0;
151 if ( $expires >= time() ) {
152 return $c->extend_session_expires( $expires );
154 $c->delete_session( "session expired" );
158 $c->_session_expires( 0 );
166 if ( my $sid = $c->sessionid ) {
167 if ( $c->session_expires ) { # > 0
169 my $session_data = $c->get_session_data("session:$sid") || return;
170 $c->_session($session_data);
172 no warnings 'uninitialized'; # ne __address
173 if ( $c->config->{session}{verify_address}
174 && $session_data->{__address} ne $c->request->address )
177 "Deleting session $sid due to address mismatch ("
178 . $session_data->{__address} . " != "
179 . $c->request->address . ")"
181 $c->delete_session("address mismatch");
185 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
186 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
187 $c->_expire_session_keys;
189 return $session_data;
199 if ( my $sid = $c->sessionid ) {
200 if ( my $flash_data = $c->_flash
201 || $c->_flash( $c->get_session_data("flash:$sid") ) )
203 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
212 sub _expire_session_keys {
213 my ( $c, $data ) = @_;
217 my $expire_times = ( $data || $c->_session || {} )->{__expire_keys} || {};
218 foreach my $key ( grep { $expire_times->{$_} < $now } keys %$expire_times ) {
219 delete $c->_session->{$key};
220 delete $expire_times->{$key};
225 my ( $c, $msg ) = @_;
227 # delete the session data
228 my $sid = $c->sessionid || return;
229 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
231 $c->delete_session_id;
233 # reset the values in the context object
234 # see the BEGIN block
235 $c->$_(undef) for @session_data_accessors;
237 $c->_session_delete_reason($msg);
240 sub session_delete_reason {
243 $c->session_is_valid; # check that it was loaded
245 $c->_session_delete_reason(@_);
248 sub session_expires {
251 if ( defined( my $expires = $c->_session_expires ) ) {
254 return $c->_load_session_expires;
258 sub extend_session_expires {
259 my ( $c, $expires ) = @_;
261 $c->_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
265 sub calculate_initial_session_expires {
267 return ( time() + $c->config->{session}{expires} );
270 sub calculate_extended_session_expires {
271 my ( $c, $prev ) = @_;
272 $c->calculate_initial_session_expires;
275 sub reset_session_expires {
276 my ( $c, $sid ) = @_;
277 $c->_session_expires( my $exp = $c->calculate_initial_session_expires );
284 return $c->_sessionid || do {
285 unless ( $c->_tried_loading_session ) {
286 $c->_tried_loading_session(1);
287 if ( defined( my $sid = $c->get_session_id ) ) {
288 if ( $c->validate_session_id($sid) ) {
289 $c->_sessionid( $sid );
292 my $err = "Tried to set invalid session ID '$sid'";
293 $c->log->error($err);
294 Catalyst::Exception->throw($err);
303 sub session_is_valid {
306 $c->_load_session unless $c->_session; # check expiry and also __address, etc
308 if ( $c->_session ) {
315 sub validate_session_id {
316 my ( $c, $sid ) = @_;
318 $sid and $sid =~ /^[a-f\d]+$/i;
324 $c->_session || $c->_load_session || do {
325 $c->create_session_id;
326 $c->initialize_session_data;
331 my ( $c, @keys ) = @_;
332 my $href = $c->_flash_keep_keys || $c->_flash_keep_keys({});
333 (@{$href}{@keys}) = ((undef) x @keys);
338 $c->_flash || $c->_load_flash || do {
339 $c->create_session_id;
344 sub session_expire_key {
345 my ( $c, %keys ) = @_;
348 @{ $c->session->{__expire_keys} }{ keys %keys } =
349 map { $now + $_ } values %keys;
352 sub initialize_session_data {
363 $c->config->{session}{verify_address}
364 ? ( __address => $c->request->address )
371 sub generate_session_id {
374 my $digest = $c->_find_digest();
375 $digest->add( $c->session_hash_seed() );
376 return $digest->hexdigest;
379 sub create_session_id {
382 my $sid = $c->generate_session_id;
384 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
386 $c->_sessionid($sid);
387 $c->reset_session_expires;
388 $c->set_session_id($sid);
395 sub session_hash_seed {
398 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
403 sub _find_digest () {
405 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
406 if ( eval { Digest->new($alg) } ) {
411 Catalyst::Exception->throw(
412 "Could not find a suitable Digest module. Please install "
413 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
417 return Digest->new($usable);
424 $c->NEXT::dump_these(),
427 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
433 sub get_session_id { shift->NEXT::get_session_id(@_) }
434 sub set_session_id { shift->NEXT::set_session_id(@_) }
435 sub delete_session_id { shift->NEXT::delete_session_id(@_) }
445 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
446 storage and client side state required to maintain session data.
450 # To get sessions to "just work", all you need to do is use these plugins:
454 Session::Store::FastMmap
455 Session::State::Cookie
458 # you can replace Store::FastMmap with Store::File - both have sensible
459 # default configurations (see their docs for details)
461 # more complicated backends are available for other scenarios (DBI storage,
465 # after you've loaded the plugins you can save session data
466 # For example, if you are writing a shopping cart, it could be implemented
469 sub add_item : Local {
470 my ( $self, $c ) = @_;
472 my $item_id = $c->req->param("item");
474 # $c->session is a hash ref, a bit like $c->stash
475 # the difference is that it' preserved across requests
477 push @{ $c->session->{items} }, $item_id;
479 $c->forward("MyView");
482 sub display_items : Local {
483 my ( $self, $c ) = @_;
485 # values in $c->session are restored
486 $c->stash->{items_to_display} =
487 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
489 $c->forward("MyView");
494 The Session plugin is the base of two related parts of functionality required
495 for session management in web applications.
497 The first part, the State, is getting the browser to repeat back a session key,
498 so that the web application can identify the client and logically string
499 several requests together into a session.
501 The second part, the Store, deals with the actual storage of information about
502 the client. This data is stored so that the it may be revived for every request
503 made by the same client.
505 This plugin links the two pieces together.
507 =head1 RECCOMENDED BACKENDS
511 =item Session::State::Cookie
513 The only really sane way to do state is using cookies.
515 =item Session::Store::File
517 A portable backend, based on Cache::File.
519 =item Session::Store::FastMmap
521 A fast and flexible backend, based on Cache::FastMmap.
531 An accessor for the session ID value.
535 Returns a hash reference that might contain unserialized values from previous
536 requests in the same session, and whose modified value will be saved for future
539 This method will automatically create a new session and session ID if none
542 =item session_expires
544 =item session_expires $reset
546 This method returns the time when the current session will expire, or 0 if
547 there is no current session. If there is a session and it already expired, it
548 will delete the session and return 0 as well.
550 If the C<$reset> parameter is true, and there is a session ID the expiry time
551 will be reset to the current time plus the time to live (see
552 L</CONFIGURATION>). This is used when creating a new session.
556 This is like Ruby on Rails' flash data structure. Think of it as a stash that
557 lasts for longer than one request, letting you redirect instead of forward.
559 The flash data will be cleaned up only on requests on which actually use
560 $c->flash (thus allowing multiple redirections), and the policy is to delete
561 all the keys which haven't changed since the flash data was loaded at the end
565 my ( $self, $c ) = @_;
567 $c->flash->{beans} = 10;
568 $c->response->redirect( $c->uri_for("foo") );
572 my ( $self, $c ) = @_;
574 my $value = $c->flash->{beans};
578 $c->response->redirect( $c->uri_for("bar") );
582 my ( $self, $c ) = @_;
584 if ( exists $c->flash->{beans} ) { # false
589 =item keep_flash @keys
591 If you wawnt to keep a flash key for the next request too, even if it hasn't
592 changed, call C<keep_flash> and pass in the keys as arguments.
594 =item session_delete_reason
596 This accessor contains a string with the reason a session was deleted. Possible
611 =item session_expire_key $key, $ttl
613 Mark a key to expire at a certain time (only useful when shorter than the
614 expiry time for the whole session).
618 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
622 $c->session_expire_key( __user => 3600 );
624 Will make the session data survive, but the user will still be logged out after
627 Note that these values are not auto extended.
631 =head1 INTERNAL METHODS
637 This method is extended to also make calls to
638 C<check_session_plugin_requirements> and C<setup_session>.
640 =item check_session_plugin_requirements
642 This method ensures that a State and a Store plugin are also in use by the
647 This method populates C<< $c->config->{session} >> with the default values
648 listed in L</CONFIGURATION>.
652 This methoid is extended.
654 It's only effect is if the (off by default) C<flash_to_stash> configuration
655 parameter is on - then it will copy the contents of the flash to the stash at
660 This method is extended and will extend the expiry time, as well as persist the
661 session data if a session exists.
663 =item delete_session REASON
665 This method is used to invalidate a session. It takes an optional parameter
666 which will be saved in C<session_delete_reason> if provided.
668 =item initialize_session_data
670 This method will initialize the internal structure of the session, and is
671 called by the C<session> method if appropriate.
673 =item create_session_id
675 Creates a new session id using C<generate_session_id> if there is no session ID
678 =item validate_session_id SID
680 Make sure a session ID is of the right format.
682 This currently ensures that the session ID string is any amount of case
683 insensitive hexadecimal characters.
685 =item generate_session_id
687 This method will return a string that can be used as a session ID. It is
688 supposed to be a reasonably random string with enough bits to prevent
689 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
690 MD5 or SHA-256, depending on the availibility of these modules.
692 =item session_hash_seed
694 This method is actually rather internal to generate_session_id, but should be
695 overridable in case you want to provide more random data.
697 Currently it returns a concatenated string which contains:
711 One value from C<rand>.
715 The stringified value of a newly allocated hash reference
719 The stringified value of the Catalyst context object
723 In the hopes that those combined values are entropic enough for most uses. If
724 this is not the case you can replace C<session_hash_seed> with e.g.
726 sub session_hash_seed {
727 open my $fh, "<", "/dev/random";
728 read $fh, my $bytes, 20;
733 Or even more directly, replace C<generate_session_id>:
735 sub generate_session_id {
736 open my $fh, "<", "/dev/random";
737 read $fh, my $bytes, 20;
739 return unpack("H*", $bytes);
742 Also have a look at L<Crypt::Random> and the various openssl bindings - these
743 modules provide APIs for cryptographically secure random data.
747 See L<Catalyst/dump_these> - ammends the session data structure to the list of
748 dumped objects if session ID is defined.
752 =head1 USING SESSIONS DURING PREPARE
754 The earliest point in time at which you may use the session data is after
755 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
757 State plugins must set $c->session ID before C<prepare_action>, and during
758 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
764 # don't touch $c->session yet!
766 $c->NEXT::prepare_action( @_ );
768 $c->session; # this is OK
769 $c->sessionid; # this is also OK
774 $c->config->{session} = {
778 All configuation parameters are provided in a hash reference under the
779 C<session> key in the configuration hash.
785 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
790 When true, C<<$c->request->address>> will be checked at prepare time. If it is
791 not the same as the address that initiated the session, the session is deleted.
795 This option makes it easier to have actions behave the same whether they were
796 forwarded to or redirected to. On prepare time it copies the contents of
797 C<flash> (if any) to the stash.
803 The hash reference returned by C<< $c->session >> contains several keys which
804 are automatically set:
810 This key no longer exists. Use C<session_expires> instead.
814 The last time a session was saved to the store.
818 The time when the session was first created.
822 The value of C<< $c->request->address >> at the time the session was created.
823 This value is only populated if C<verify_address> is true in the configuration.
829 =head2 Round the Robin Proxies
831 C<verify_address> could make your site inaccessible to users who are behind
832 load balanced proxies. Some ISPs may give a different IP to each request by the
833 same client due to this type of proxying. If addresses are verified these
834 users' sessions cannot persist.
836 To let these users access your site you can either disable address verification
837 as a whole, or provide a checkbox in the login dialog that tells the server
838 that it's OK for the address of the client to change. When the server sees that
839 this box is checked it should delete the C<__address> sepcial key from the
840 session hash when the hash is first created.
842 =head2 Race Conditions
844 In this day and age where cleaning detergents and dutch football (not the
845 american kind) teams roam the plains in great numbers, requests may happen
846 simultaneously. This means that there is some risk of session data being
847 overwritten, like this:
853 request a starts, request b starts, with the same session id
857 session data is loaded in request a
861 session data is loaded in request b
865 session data is changed in request a
869 request a finishes, session data is updated and written to store
873 request b finishes, session data is updated and written to store, overwriting
878 If this is a concern in your application, a soon to be developed locking
879 solution is the only safe way to go. This will have a bigger overhead.
881 For applications where any given user is only making one request at a time this
882 plugin should be safe enough.
890 =item Christian Hansen
892 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
894 =item Sebastian Riedel
898 And countless other contributers from #catalyst. Thanks guys!
900 =head1 COPYRIGHT & LICENSE
902 Copyright (c) 2005 the aforementioned authors. All rights
903 reserved. This program is free software; you can redistribute
904 it and/or modify it under the same terms as Perl itself.