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/
38 $c->check_session_plugin_requirements;
44 sub check_session_plugin_requirements {
47 unless ( $c->isa("Catalyst::Plugin::Session::State")
48 && $c->isa("Catalyst::Plugin::Session::Store") )
51 ( "The Session plugin requires both Session::State "
52 . "and Session::Store plugins to be used as well." );
55 Catalyst::Exception->throw($err);
62 my $cfg = ( $c->config->{session} ||= {} );
70 $c->NEXT::setup_session();
76 if ( $c->config->{session}{flash_to_stash}
78 and my $flash_data = $c->flash )
80 @{ $c->stash }{ keys %$flash_data } = values %$flash_data;
83 $c->NEXT::prepare_action(@_);
92 $c->NEXT::finalize(@_);
98 if ( my $sid = $c->_sessionid ) {
100 # all sessions are extended at the end of the request
103 if ( my $expires = $c->session_expires ) {
104 $c->store_session_data( "expires:$sid" => $expires );
107 if ( my $session_data = $c->_session ) {
109 no warnings 'uninitialized';
110 if ( Object::Signature::signature($session_data) ne
111 $c->_session_data_sig )
113 $session_data->{__updated} = $now;
114 $c->store_session_data( "session:$sid" => $session_data );
123 if ( my $sid = $c->_sessionid ) {
124 if ( my $flash_data = $c->_flash ) {
126 my $hashes = $c->_flash_key_hashes || {};
127 my $keep = $c->_flash_keep_keys || {};
128 foreach my $key ( keys %$hashes ) {
129 if ( !exists $keep->{$key} and Object::Signature::signature( \$flash_data->{$key} ) eq $hashes->{$key} ) {
130 delete $flash_data->{$key};
135 $c->store_session_data( "flash:$sid", $flash_data );
138 $c->delete_session_data("flash:$sid");
147 if ( my $sid = $c->_sessionid ) {
148 if ( $c->session_expires ) { # > 0
150 my $session_data = $c->get_session_data("session:$sid");
151 $c->_session($session_data);
153 no warnings 'uninitialized'; # ne __address
154 if ( $c->config->{session}{verify_address}
155 && $session_data->{__address} ne $c->request->address )
158 "Deleting session $sid due to address mismatch ("
159 . $session_data->{__address} . " != "
160 . $c->request->address . ")",
162 $c->delete_session("address mismatch");
166 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
167 $c->_session_data_sig( Object::Signature::signature($session_data) ) if $session_data;
168 $c->_expire_session_keys;
170 return $session_data;
180 if ( my $sid = $c->_sessionid ) {
181 if ( my $flash_data = $c->_flash
182 || $c->_flash( $c->get_session_data("flash:$sid") ) )
184 $c->_flash_key_hashes({ map { $_ => Object::Signature::signature( \$flash_data->{$_} ) } keys %$flash_data });
192 sub _expire_session_keys {
193 my ( $c, $data ) = @_;
197 my $expiry = ( $data || $c->_session || {} )->{__expire_keys} || {};
198 foreach my $key ( grep { $expiry->{$_} < $now } keys %$expiry ) {
199 delete $c->_session->{$key};
200 delete $expiry->{$key};
205 my ( $c, $msg ) = @_;
207 # delete the session data
208 my $sid = $c->_sessionid || return;
209 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
211 # reset the values in the context object
212 # see the BEGIN block
213 $c->$_(undef) for @session_data_accessors;
215 $c->_session_delete_reason($msg);
218 sub session_delete_reason {
222 if ( $c->_sessionid && !$c->_session ); # must verify session data
224 $c->_session_delete_reason(@_);
227 sub session_expires {
228 my ( $c, $should_create ) = @_;
230 $c->_session_expires || do {
231 if ( my $sid = $c->_sessionid ) {
234 if ( !$should_create ) {
235 if ( ( $c->get_session_data("expires:$sid") || 0 ) < $now ) {
238 $c->log->debug("Deleting session $sid (expired)")
240 $c->delete_session("session expired");
245 return $c->_session_expires(
246 $now + $c->config->{session}{expires} );
255 if($c->_sessionid()) {
256 $c->log->warn('Session ID already set, ignoring.');
257 return $c->_sessionid();
259 if ( $c->validate_session_id( my $sid = shift ) ) {
260 $c->_sessionid($sid);
261 return unless defined wantarray;
264 my $err = "Tried to set invalid session ID '$sid'";
265 $c->log->error($err);
266 Catalyst::Exception->throw($err);
271 if ( $c->_sessionid && !$c->_session ); # must verify session data
273 return $c->_sessionid;
276 sub validate_session_id {
277 my ( $c, $sid ) = @_;
279 $sid and $sid =~ /^[a-f\d]+$/i;
285 $c->_session || $c->_load_session || do {
286 $c->create_session_id;
288 $c->initialize_session_data;
293 my ( $c, @keys ) = @_;
294 ($c->_flash_keep_keys->{@keys}) = ((undef) x @keys);
299 $c->_flash || $c->_load_flash || do {
300 $c->create_session_id;
305 sub session_expire_key {
306 my ( $c, %keys ) = @_;
309 @{ $c->session->{__expire_keys} }{ keys %keys } =
310 map { $now + $_ } values %keys;
313 sub initialize_session_data {
324 $c->config->{session}{verify_address}
325 ? ( __address => $c->request->address )
332 sub generate_session_id {
335 my $digest = $c->_find_digest();
336 $digest->add( $c->session_hash_seed() );
337 return $digest->hexdigest;
340 sub create_session_id {
343 if ( !$c->_sessionid ) {
344 my $sid = $c->generate_session_id;
346 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
349 $c->session_expires(1);
355 sub session_hash_seed {
358 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
363 sub _find_digest () {
365 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
366 if ( eval { Digest->new($alg) } ) {
371 Catalyst::Exception->throw(
372 "Could not find a suitable Digest module. Please install "
373 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
377 return Digest->new($usable);
384 $c->NEXT::dump_these(),
387 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
400 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
401 storage and client side state required to maintain session data.
405 # To get sessions to "just work", all you need to do is use these plugins:
409 Session::Store::FastMmap
410 Session::State::Cookie
413 # you can replace Store::FastMmap with Store::File - both have sensible
414 # default configurations (see their docs for details)
416 # more complicated backends are available for other scenarios (DBI storage,
420 # after you've loaded the plugins you can save session data
421 # For example, if you are writing a shopping cart, it could be implemented
424 sub add_item : Local {
425 my ( $self, $c ) = @_;
427 my $item_id = $c->req->param("item");
429 # $c->session is a hash ref, a bit like $c->stash
430 # the difference is that it' preserved across requests
432 push @{ $c->session->{items} }, $item_id;
434 $c->forward("MyView");
437 sub display_items : Local {
438 my ( $self, $c ) = @_;
440 # values in $c->session are restored
441 $c->stash->{items_to_display} =
442 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
444 $c->forward("MyView");
449 The Session plugin is the base of two related parts of functionality required
450 for session management in web applications.
452 The first part, the State, is getting the browser to repeat back a session key,
453 so that the web application can identify the client and logically string
454 several requests together into a session.
456 The second part, the Store, deals with the actual storage of information about
457 the client. This data is stored so that the it may be revived for every request
458 made by the same client.
460 This plugin links the two pieces together.
462 =head1 RECCOMENDED BACKENDS
466 =item Session::State::Cookie
468 The only really sane way to do state is using cookies.
470 =item Session::Store::File
472 A portable backend, based on Cache::File.
474 =item Session::Store::FastMmap
476 A fast and flexible backend, based on Cache::FastMmap.
486 An accessor for the session ID value.
490 Returns a hash reference that might contain unserialized values from previous
491 requests in the same session, and whose modified value will be saved for future
494 This method will automatically create a new session and session ID if none
497 =item session_expires
499 =item session_expires $reset
501 This method returns the time when the current session will expire, or 0 if
502 there is no current session. If there is a session and it already expired, it
503 will delete the session and return 0 as well.
505 If the C<$reset> parameter is true, and there is a session ID the expiry time
506 will be reset to the current time plus the time to live (see
507 L</CONFIGURATION>). This is used when creating a new session.
511 This is like Ruby on Rails' flash data structure. Think of it as a stash that
512 lasts for longer than one request, letting you redirect instead of forward.
514 The flash data will be cleaned up only on requests on which actually use
515 $c->flash (thus allowing multiple redirections), and the policy is to delete
516 all the keys which haven't changed since the flash data was loaded at the end
520 my ( $self, $c ) = @_;
522 $c->flash->{beans} = 10;
523 $c->response->redirect( $c->uri_for("foo") );
527 my ( $self, $c ) = @_;
529 my $value = $c->flash->{beans};
533 $c->response->redirect( $c->uri_for("bar") );
537 my ( $self, $c ) = @_;
539 if ( exists $c->flash->{beans} ) { # false
544 =item keep_flash @keys
546 If you wawnt to keep a flash key for the next request too, even if it hasn't
547 changed, call C<keep_flash> and pass in the keys as arguments.
549 =item session_delete_reason
551 This accessor contains a string with the reason a session was deleted. Possible
566 =item session_expire_key $key, $ttl
568 Mark a key to expire at a certain time (only useful when shorter than the
569 expiry time for the whole session).
573 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
577 $c->session_expire_key( __user => 3600 );
579 Will make the session data survive, but the user will still be logged out after
582 Note that these values are not auto extended.
586 =head1 INTERNAL METHODS
592 This method is extended to also make calls to
593 C<check_session_plugin_requirements> and C<setup_session>.
595 =item check_session_plugin_requirements
597 This method ensures that a State and a Store plugin are also in use by the
602 This method populates C<< $c->config->{session} >> with the default values
603 listed in L</CONFIGURATION>.
607 This methoid is extended.
609 It's only effect is if the (off by default) C<flash_to_stash> configuration
610 parameter is on - then it will copy the contents of the flash to the stash at
615 This method is extended and will extend the expiry time, as well as persist the
616 session data if a session exists.
618 =item delete_session REASON
620 This method is used to invalidate a session. It takes an optional parameter
621 which will be saved in C<session_delete_reason> if provided.
623 =item initialize_session_data
625 This method will initialize the internal structure of the session, and is
626 called by the C<session> method if appropriate.
628 =item create_session_id
630 Creates a new session id using C<generate_session_id> if there is no session ID
633 =item validate_session_id SID
635 Make sure a session ID is of the right format.
637 This currently ensures that the session ID string is any amount of case
638 insensitive hexadecimal characters.
640 =item generate_session_id
642 This method will return a string that can be used as a session ID. It is
643 supposed to be a reasonably random string with enough bits to prevent
644 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
645 MD5 or SHA-256, depending on the availibility of these modules.
647 =item session_hash_seed
649 This method is actually rather internal to generate_session_id, but should be
650 overridable in case you want to provide more random data.
652 Currently it returns a concatenated string which contains:
666 One value from C<rand>.
670 The stringified value of a newly allocated hash reference
674 The stringified value of the Catalyst context object
678 In the hopes that those combined values are entropic enough for most uses. If
679 this is not the case you can replace C<session_hash_seed> with e.g.
681 sub session_hash_seed {
682 open my $fh, "<", "/dev/random";
683 read $fh, my $bytes, 20;
688 Or even more directly, replace C<generate_session_id>:
690 sub generate_session_id {
691 open my $fh, "<", "/dev/random";
692 read $fh, my $bytes, 20;
694 return unpack("H*", $bytes);
697 Also have a look at L<Crypt::Random> and the various openssl bindings - these
698 modules provide APIs for cryptographically secure random data.
702 See L<Catalyst/dump_these> - ammends the session data structure to the list of
703 dumped objects if session ID is defined.
707 =head1 USING SESSIONS DURING PREPARE
709 The earliest point in time at which you may use the session data is after
710 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
712 State plugins must set $c->session ID before C<prepare_action>, and during
713 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
719 # don't touch $c->session yet!
721 $c->NEXT::prepare_action( @_ );
723 $c->session; # this is OK
724 $c->sessionid; # this is also OK
729 $c->config->{session} = {
733 All configuation parameters are provided in a hash reference under the
734 C<session> key in the configuration hash.
740 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
745 When true, C<<$c->request->address>> will be checked at prepare time. If it is
746 not the same as the address that initiated the session, the session is deleted.
750 This option makes it easier to have actions behave the same whether they were
751 forwarded to or redirected to. On prepare time it copies the contents of
752 C<flash> (if any) to the stash.
758 The hash reference returned by C<< $c->session >> contains several keys which
759 are automatically set:
765 This key no longer exists. Use C<session_expires> instead.
769 The last time a session was saved to the store.
773 The time when the session was first created.
777 The value of C<< $c->request->address >> at the time the session was created.
778 This value is only populated if C<verify_address> is true in the configuration.
784 =head2 Round the Robin Proxies
786 C<verify_address> could make your site inaccessible to users who are behind
787 load balanced proxies. Some ISPs may give a different IP to each request by the
788 same client due to this type of proxying. If addresses are verified these
789 users' sessions cannot persist.
791 To let these users access your site you can either disable address verification
792 as a whole, or provide a checkbox in the login dialog that tells the server
793 that it's OK for the address of the client to change. When the server sees that
794 this box is checked it should delete the C<__address> sepcial key from the
795 session hash when the hash is first created.
797 =head2 Race Conditions
799 In this day and age where cleaning detergents and dutch football (not the
800 american kind) teams roam the plains in great numbers, requests may happen
801 simultaneously. This means that there is some risk of session data being
802 overwritten, like this:
808 request a starts, request b starts, with the same session id
812 session data is loaded in request a
816 session data is loaded in request b
820 session data is changed in request a
824 request a finishes, session data is updated and written to store
828 request b finishes, session data is updated and written to store, overwriting
833 If this is a concern in your application, a soon to be developed locking
834 solution is the only safe way to go. This will have a bigger overhead.
836 For applications where any given user is only making one request at a time this
837 plugin should be safe enough.
845 =item Christian Hansen
847 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
849 =item Sebastian Riedel
853 And countless other contributers from #catalyst. Thanks guys!
855 =head1 COPYRIGHT & LICENSE
857 Copyright (c) 2005 the aforementioned authors. All rights
858 reserved. This program is free software; you can redistribute
859 it and/or modify it under the same terms as Perl itself.