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 ) = @_;
260 $c->_session_expires( my $updated = $c->calculate_extended_session_expires( $expires ) );
261 $c->extend_session_id( $c->sessionid, $updated );
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(@_) }
436 sub extend_session_id { shift->NEXT::extend_session_id(@_) }
446 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
447 storage and client side state required to maintain session data.
451 # To get sessions to "just work", all you need to do is use these plugins:
455 Session::Store::FastMmap
456 Session::State::Cookie
459 # you can replace Store::FastMmap with Store::File - both have sensible
460 # default configurations (see their docs for details)
462 # more complicated backends are available for other scenarios (DBI storage,
466 # after you've loaded the plugins you can save session data
467 # For example, if you are writing a shopping cart, it could be implemented
470 sub add_item : Local {
471 my ( $self, $c ) = @_;
473 my $item_id = $c->req->param("item");
475 # $c->session is a hash ref, a bit like $c->stash
476 # the difference is that it' preserved across requests
478 push @{ $c->session->{items} }, $item_id;
480 $c->forward("MyView");
483 sub display_items : Local {
484 my ( $self, $c ) = @_;
486 # values in $c->session are restored
487 $c->stash->{items_to_display} =
488 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
490 $c->forward("MyView");
495 The Session plugin is the base of two related parts of functionality required
496 for session management in web applications.
498 The first part, the State, is getting the browser to repeat back a session key,
499 so that the web application can identify the client and logically string
500 several requests together into a session.
502 The second part, the Store, deals with the actual storage of information about
503 the client. This data is stored so that the it may be revived for every request
504 made by the same client.
506 This plugin links the two pieces together.
508 =head1 RECCOMENDED BACKENDS
512 =item Session::State::Cookie
514 The only really sane way to do state is using cookies.
516 =item Session::Store::File
518 A portable backend, based on Cache::File.
520 =item Session::Store::FastMmap
522 A fast and flexible backend, based on Cache::FastMmap.
532 An accessor for the session ID value.
536 Returns a hash reference that might contain unserialized values from previous
537 requests in the same session, and whose modified value will be saved for future
540 This method will automatically create a new session and session ID if none
543 =item session_expires
545 =item session_expires $reset
547 This method returns the time when the current session will expire, or 0 if
548 there is no current session. If there is a session and it already expired, it
549 will delete the session and return 0 as well.
551 If the C<$reset> parameter is true, and there is a session ID the expiry time
552 will be reset to the current time plus the time to live (see
553 L</CONFIGURATION>). This is used when creating a new session.
557 This is like Ruby on Rails' flash data structure. Think of it as a stash that
558 lasts for longer than one request, letting you redirect instead of forward.
560 The flash data will be cleaned up only on requests on which actually use
561 $c->flash (thus allowing multiple redirections), and the policy is to delete
562 all the keys which haven't changed since the flash data was loaded at the end
566 my ( $self, $c ) = @_;
568 $c->flash->{beans} = 10;
569 $c->response->redirect( $c->uri_for("foo") );
573 my ( $self, $c ) = @_;
575 my $value = $c->flash->{beans};
579 $c->response->redirect( $c->uri_for("bar") );
583 my ( $self, $c ) = @_;
585 if ( exists $c->flash->{beans} ) { # false
590 =item keep_flash @keys
592 If you wawnt to keep a flash key for the next request too, even if it hasn't
593 changed, call C<keep_flash> and pass in the keys as arguments.
595 =item delete_session REASON
597 This method is used to invalidate a session. It takes an optional parameter
598 which will be saved in C<session_delete_reason> if provided.
600 =item session_delete_reason
602 This accessor contains a string with the reason a session was deleted. Possible
617 =item session_expire_key $key, $ttl
619 Mark a key to expire at a certain time (only useful when shorter than the
620 expiry time for the whole session).
624 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
628 $c->session_expire_key( __user => 3600 );
630 Will make the session data survive, but the user will still be logged out after
633 Note that these values are not auto extended.
637 =head1 INTERNAL METHODS
643 This method is extended to also make calls to
644 C<check_session_plugin_requirements> and C<setup_session>.
646 =item check_session_plugin_requirements
648 This method ensures that a State and a Store plugin are also in use by the
653 This method populates C<< $c->config->{session} >> with the default values
654 listed in L</CONFIGURATION>.
658 This methoid is extended.
660 It's only effect is if the (off by default) C<flash_to_stash> configuration
661 parameter is on - then it will copy the contents of the flash to the stash at
666 This method is extended and will extend the expiry time, as well as persist the
667 session data if a session exists.
669 =item initialize_session_data
671 This method will initialize the internal structure of the session, and is
672 called by the C<session> method if appropriate.
674 =item create_session_id
676 Creates a new session id using C<generate_session_id> if there is no session ID
679 =item validate_session_id SID
681 Make sure a session ID is of the right format.
683 This currently ensures that the session ID string is any amount of case
684 insensitive hexadecimal characters.
686 =item generate_session_id
688 This method will return a string that can be used as a session ID. It is
689 supposed to be a reasonably random string with enough bits to prevent
690 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
691 MD5 or SHA-256, depending on the availibility of these modules.
693 =item session_hash_seed
695 This method is actually rather internal to generate_session_id, but should be
696 overridable in case you want to provide more random data.
698 Currently it returns a concatenated string which contains:
712 One value from C<rand>.
716 The stringified value of a newly allocated hash reference
720 The stringified value of the Catalyst context object
724 In the hopes that those combined values are entropic enough for most uses. If
725 this is not the case you can replace C<session_hash_seed> with e.g.
727 sub session_hash_seed {
728 open my $fh, "<", "/dev/random";
729 read $fh, my $bytes, 20;
734 Or even more directly, replace C<generate_session_id>:
736 sub generate_session_id {
737 open my $fh, "<", "/dev/random";
738 read $fh, my $bytes, 20;
740 return unpack("H*", $bytes);
743 Also have a look at L<Crypt::Random> and the various openssl bindings - these
744 modules provide APIs for cryptographically secure random data.
748 See L<Catalyst/dump_these> - ammends the session data structure to the list of
749 dumped objects if session ID is defined.
753 =head1 USING SESSIONS DURING PREPARE
755 The earliest point in time at which you may use the session data is after
756 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
758 State plugins must set $c->session ID before C<prepare_action>, and during
759 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
765 # don't touch $c->session yet!
767 $c->NEXT::prepare_action( @_ );
769 $c->session; # this is OK
770 $c->sessionid; # this is also OK
775 $c->config->{session} = {
779 All configuation parameters are provided in a hash reference under the
780 C<session> key in the configuration hash.
786 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
791 When true, C<<$c->request->address>> will be checked at prepare time. If it is
792 not the same as the address that initiated the session, the session is deleted.
796 This option makes it easier to have actions behave the same whether they were
797 forwarded to or redirected to. On prepare time it copies the contents of
798 C<flash> (if any) to the stash.
804 The hash reference returned by C<< $c->session >> contains several keys which
805 are automatically set:
811 This key no longer exists. Use C<session_expires> instead.
815 The last time a session was saved to the store.
819 The time when the session was first created.
823 The value of C<< $c->request->address >> at the time the session was created.
824 This value is only populated if C<verify_address> is true in the configuration.
830 =head2 Round the Robin Proxies
832 C<verify_address> could make your site inaccessible to users who are behind
833 load balanced proxies. Some ISPs may give a different IP to each request by the
834 same client due to this type of proxying. If addresses are verified these
835 users' sessions cannot persist.
837 To let these users access your site you can either disable address verification
838 as a whole, or provide a checkbox in the login dialog that tells the server
839 that it's OK for the address of the client to change. When the server sees that
840 this box is checked it should delete the C<__address> sepcial key from the
841 session hash when the hash is first created.
843 =head2 Race Conditions
845 In this day and age where cleaning detergents and dutch football (not the
846 american kind) teams roam the plains in great numbers, requests may happen
847 simultaneously. This means that there is some risk of session data being
848 overwritten, like this:
854 request a starts, request b starts, with the same session id
858 session data is loaded in request a
862 session data is loaded in request b
866 session data is changed in request a
870 request a finishes, session data is updated and written to store
874 request b finishes, session data is updated and written to store, overwriting
879 If this is a concern in your application, a soon to be developed locking
880 solution is the only safe way to go. This will have a bigger overhead.
882 For applications where any given user is only making one request at a time this
883 plugin should be safe enough.
891 =item Christian Hansen
893 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
895 =item Sebastian Riedel
899 And countless other contributers from #catalyst. Thanks guys!
901 =head1 COPYRIGHT & LICENSE
903 Copyright (c) 2005 the aforementioned authors. All rights
904 reserved. This program is free software; you can redistribute
905 it and/or modify it under the same terms as Perl itself.