3 package Catalyst::Plugin::Session;
4 use base qw/Class::Accessor::Fast/;
10 use Catalyst::Exception ();
13 use Object::Signature ();
15 our $VERSION = "0.04";
17 my @session_data_accessors; # used in delete_session
19 __PACKAGE__->mk_accessors(
20 "_session_delete_reason",
21 @session_data_accessors = qw/
37 $c->check_session_plugin_requirements;
43 sub check_session_plugin_requirements {
46 unless ( $c->isa("Catalyst::Plugin::Session::State")
47 && $c->isa("Catalyst::Plugin::Session::Store") )
50 ( "The Session plugin requires both Session::State "
51 . "and Session::Store plugins to be used as well." );
54 Catalyst::Exception->throw($err);
61 my $cfg = ( $c->config->{session} ||= {} );
69 $c->NEXT::setup_session();
75 if ( $c->config->{session}{flash_to_stash}
77 and my $flash_data = $c->flash )
79 @{ $c->stash }{ keys %$flash_data } = values %$flash_data;
82 $c->NEXT::prepare_action(@_);
91 $c->NEXT::finalize(@_);
97 if ( my $sid = $c->_sessionid ) {
99 # all sessions are extended at the end of the request
102 if ( my $expires = $c->session_expires ) {
103 $c->store_session_data( "expires:$sid" => $expires );
106 if ( my $session_data = $c->_session ) {
108 no warnings 'uninitialized';
109 if ( Object::Signature::signature($session_data) ne
110 $c->_session_data_sig )
112 $session_data->{__updated} = $now;
113 $c->store_session_data( "session:$sid" => $session_data );
122 if ( my $sid = $c->_sessionid ) {
123 my $flash_data = $c->_flash || {};
125 delete @{$flash_data}{ @{ $c->_flash_stale_keys || [] } };
127 if (%$flash_data) { # damn 'my' declarations
128 $c->store_session_data( "flash:$sid", $flash_data );
131 $c->delete_session_data("flash:$sid");
139 if ( my $sid = $c->_sessionid ) {
140 if ( $c->session_expires ) { # > 0
142 my $session_data = $c->get_session_data("session:$sid");
143 $c->_session($session_data);
145 no warnings 'uninitialized'; # ne __address
146 if ( $c->config->{session}{verify_address}
147 && $session_data->{__address} ne $c->request->address )
150 "Deleting session $sid due to address mismatch ("
151 . $session_data->{__address} . " != "
152 . $c->request->address . ")",
154 $c->delete_session("address mismatch");
158 $c->log->debug(qq/Restored session "$sid"/) if $c->debug;
159 $c->_session_data_sig(
160 Object::Signature::signature($session_data) );
161 $c->_expire_session_keys;
163 return $session_data;
173 if ( my $sid = $c->_sessionid ) {
174 if ( my $flash_data = $c->_flash
175 || $c->_flash( $c->get_session_data("flash:$sid") ) )
177 $c->_flash_stale_keys( [ keys %$flash_data ] );
185 sub _expire_session_keys {
186 my ( $c, $data ) = @_;
190 my $expiry = ( $data || $c->_session || {} )->{__expire_keys} || {};
191 foreach my $key ( grep { $expiry->{$_} < $now } keys %$expiry ) {
192 delete $c->_session->{$key};
193 delete $expiry->{$key};
198 my ( $c, $msg ) = @_;
200 # delete the session data
201 my $sid = $c->_sessionid || return;
202 $c->delete_session_data("${_}:${sid}") for qw/session expires flash/;
204 # reset the values in the context object
205 # see the BEGIN block
206 $c->$_(undef) for @session_data_accessors;
208 $c->_session_delete_reason($msg);
211 sub session_delete_reason {
215 if ( $c->_sessionid && !$c->_session ); # must verify session data
217 $c->_session_delete_reason(@_);
220 sub session_expires {
221 my ( $c, $should_create ) = @_;
223 $c->_session_expires || do {
224 if ( my $sid = $c->_sessionid ) {
227 if ( !$should_create ) {
228 if ( ( $c->get_session_data("expires:$sid") || 0 ) < $now ) {
231 $c->log->debug("Deleting session $sid (expired)")
233 $c->delete_session("session expired");
238 return $c->_session_expires(
239 $now + $c->config->{session}{expires} );
248 if ( $c->validate_session_id( my $sid = shift ) ) {
249 $c->_sessionid($sid);
250 return unless defined wantarray;
253 my $err = "Tried to set invalid session ID '$sid'";
254 $c->log->error($err);
255 Catalyst::Exception->throw($err);
260 if ( $c->_sessionid && !$c->_session ); # must verify session data
262 return $c->_sessionid;
265 sub validate_session_id {
266 my ( $c, $sid ) = @_;
268 $sid and $sid =~ /^[a-f\d]+$/i;
274 $c->_session || $c->_load_session || do {
275 $c->create_session_id;
277 $c->initialize_session_data;
283 $c->_flash || $c->_load_flash || do {
284 $c->create_session_id;
289 sub session_expire_key {
290 my ( $c, %keys ) = @_;
293 @{ $c->session->{__expire_keys} }{ keys %keys } =
294 map { $now + $_ } values %keys;
297 sub initialize_session_data {
308 $c->config->{session}{verify_address}
309 ? ( __address => $c->request->address )
316 sub generate_session_id {
319 my $digest = $c->_find_digest();
320 $digest->add( $c->session_hash_seed() );
321 return $digest->hexdigest;
324 sub create_session_id {
327 if ( !$c->_sessionid ) {
328 my $sid = $c->generate_session_id;
330 $c->log->debug(qq/Created session "$sid"/) if $c->debug;
333 $c->session_expires(1);
339 sub session_hash_seed {
342 return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), );
347 sub _find_digest () {
349 foreach my $alg (qw/SHA-1 SHA-256 MD5/) {
350 if ( eval { Digest->new($alg) } ) {
355 Catalyst::Exception->throw(
356 "Could not find a suitable Digest module. Please install "
357 . "Digest::SHA1, Digest::SHA, or Digest::MD5" )
361 return Digest->new($usable);
368 $c->NEXT::dump_these(),
371 ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], )
384 Catalyst::Plugin::Session - Generic Session plugin - ties together server side
385 storage and client side state required to maintain session data.
389 # To get sessions to "just work", all you need to do is use these plugins:
393 Session::Store::FastMmap
394 Session::State::Cookie
397 # you can replace Store::FastMmap with Store::File - both have sensible
398 # default configurations (see their docs for details)
400 # more complicated backends are available for other scenarios (DBI storage,
404 # after you've loaded the plugins you can save session data
405 # For example, if you are writing a shopping cart, it could be implemented
408 sub add_item : Local {
409 my ( $self, $c ) = @_;
411 my $item_id = $c->req->param("item");
413 # $c->session is a hash ref, a bit like $c->stash
414 # the difference is that it' preserved across requests
416 push @{ $c->session->{items} }, $item_id;
418 $c->forward("MyView");
421 sub display_items : Local {
422 my ( $self, $c ) = @_;
424 # values in $c->session are restored
425 $c->stash->{items_to_display} =
426 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];
428 $c->forward("MyView");
433 The Session plugin is the base of two related parts of functionality required
434 for session management in web applications.
436 The first part, the State, is getting the browser to repeat back a session key,
437 so that the web application can identify the client and logically string
438 several requests together into a session.
440 The second part, the Store, deals with the actual storage of information about
441 the client. This data is stored so that the it may be revived for every request
442 made by the same client.
444 This plugin links the two pieces together.
446 =head1 RECCOMENDED BACKENDS
450 =item Session::State::Cookie
452 The only really sane way to do state is using cookies.
454 =item Session::Store::File
456 A portable backend, based on Cache::File.
458 =item Session::Store::FastMmap
460 A fast and flexible backend, based on Cache::FastMmap.
470 An accessor for the session ID value.
474 Returns a hash reference that might contain unserialized values from previous
475 requests in the same session, and whose modified value will be saved for future
478 This method will automatically create a new session and session ID if none
481 =item session_expires
483 =item session_expires $reset
485 This method returns the time when the current session will expire, or 0 if
486 there is no current session. If there is a session and it already expired, it
487 will delete the session and return 0 as well.
489 If the C<$reset> parameter is true, and there is a session ID the expiry time
490 will be reset to the current time plus the time to live (see
491 L</CONFIGURATION>). This is used when creating a new session.
495 This is like Ruby on Rails' flash data structure. Think of it as a stash that
496 lasts a single redirect, not only a forward.
499 my ( $self, $c ) = @_;
501 $c->flash->{beans} = 10;
502 $c->response->redirect( $c->uri_for("foo") );
506 my ( $self, $c ) = @_;
508 my $value = $c->flash->{beans};
512 $c->response->redirect( $c->uri_for("bar") );
516 my ( $self, $c ) = @_;
518 if ( exists $c->flash->{beans} ) { # false
523 =item session_delete_reason
525 This accessor contains a string with the reason a session was deleted. Possible
540 =item session_expire_key $key, $ttl
542 Mark a key to expire at a certain time (only useful when shorter than the
543 expiry time for the whole session).
547 __PACKAGE__->config->{session}{expires} = 1000000000000; # forever
551 $c->session_expire_key( __user => 3600 );
553 Will make the session data survive, but the user will still be logged out after
556 Note that these values are not auto extended.
560 =head1 INTERNAL METHODS
566 This method is extended to also make calls to
567 C<check_session_plugin_requirements> and C<setup_session>.
569 =item check_session_plugin_requirements
571 This method ensures that a State and a Store plugin are also in use by the
576 This method populates C<< $c->config->{session} >> with the default values
577 listed in L</CONFIGURATION>.
581 This methoid is extended.
583 It's only effect is if the (off by default) C<flash_to_stash> configuration
584 parameter is on - then it will copy the contents of the flash to the stash at
589 This method is extended and will extend the expiry time, as well as persist the
590 session data if a session exists.
592 =item delete_session REASON
594 This method is used to invalidate a session. It takes an optional parameter
595 which will be saved in C<session_delete_reason> if provided.
597 =item initialize_session_data
599 This method will initialize the internal structure of the session, and is
600 called by the C<session> method if appropriate.
602 =item create_session_id
604 Creates a new session id using C<generate_session_id> if there is no session ID
607 =item validate_session_id SID
609 Make sure a session ID is of the right format.
611 This currently ensures that the session ID string is any amount of case
612 insensitive hexadecimal characters.
614 =item generate_session_id
616 This method will return a string that can be used as a session ID. It is
617 supposed to be a reasonably random string with enough bits to prevent
618 collision. It basically takes C<session_hash_seed> and hashes it using SHA-1,
619 MD5 or SHA-256, depending on the availibility of these modules.
621 =item session_hash_seed
623 This method is actually rather internal to generate_session_id, but should be
624 overridable in case you want to provide more random data.
626 Currently it returns a concatenated string which contains:
640 One value from C<rand>.
644 The stringified value of a newly allocated hash reference
648 The stringified value of the Catalyst context object
652 In the hopes that those combined values are entropic enough for most uses. If
653 this is not the case you can replace C<session_hash_seed> with e.g.
655 sub session_hash_seed {
656 open my $fh, "<", "/dev/random";
657 read $fh, my $bytes, 20;
662 Or even more directly, replace C<generate_session_id>:
664 sub generate_session_id {
665 open my $fh, "<", "/dev/random";
666 read $fh, my $bytes, 20;
668 return unpack("H*", $bytes);
671 Also have a look at L<Crypt::Random> and the various openssl bindings - these
672 modules provide APIs for cryptographically secure random data.
676 See L<Catalyst/dump_these> - ammends the session data structure to the list of
677 dumped objects if session ID is defined.
681 =head1 USING SESSIONS DURING PREPARE
683 The earliest point in time at which you may use the session data is after
684 L<Catalyst::Plugin::Session>'s C<prepare_action> has finished.
686 State plugins must set $c->session ID before C<prepare_action>, and during
687 C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from
693 # don't touch $c->session yet!
695 $c->NEXT::prepare_action( @_ );
697 $c->session; # this is OK
698 $c->sessionid; # this is also OK
703 $c->config->{session} = {
707 All configuation parameters are provided in a hash reference under the
708 C<session> key in the configuration hash.
714 The time-to-live of each session, expressed in seconds. Defaults to 7200 (two
719 When true, C<<$c->request->address>> will be checked at prepare time. If it is
720 not the same as the address that initiated the session, the session is deleted.
724 This option makes it easier to have actions behave the same whether they were
725 forwarded to or redirected to. On prepare time it copies the contents of
726 C<flash> (if any) to the stash.
732 The hash reference returned by C<< $c->session >> contains several keys which
733 are automatically set:
739 This key no longer exists. Use C<session_expires> instead.
743 The last time a session was saved to the store.
747 The time when the session was first created.
751 The value of C<< $c->request->address >> at the time the session was created.
752 This value is only populated if C<verify_address> is true in the configuration.
758 =head2 Round the Robin Proxies
760 C<verify_address> could make your site inaccessible to users who are behind
761 load balanced proxies. Some ISPs may give a different IP to each request by the
762 same client due to this type of proxying. If addresses are verified these
763 users' sessions cannot persist.
765 To let these users access your site you can either disable address verification
766 as a whole, or provide a checkbox in the login dialog that tells the server
767 that it's OK for the address of the client to change. When the server sees that
768 this box is checked it should delete the C<__address> sepcial key from the
769 session hash when the hash is first created.
771 =head2 Race Conditions
773 In this day and age where cleaning detergents and dutch football (not the
774 american kind) teams roam the plains in great numbers, requests may happen
775 simultaneously. This means that there is some risk of session data being
776 overwritten, like this:
782 request a starts, request b starts, with the same session id
786 session data is loaded in request a
790 session data is loaded in request b
794 session data is changed in request a
798 request a finishes, session data is updated and written to store
802 request b finishes, session data is updated and written to store, overwriting
807 If this is a concern in your application, a soon to be developed locking
808 solution is the only safe way to go. This will have a bigger overhead.
810 For applications where any given user is only making one request at a time this
811 plugin should be safe enough.
819 =item Christian Hansen
821 =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer)
823 =item Sebastian Riedel
827 And countless other contributers from #catalyst. Thanks guys!
829 =head1 COPYRIGHT & LICENSE
831 Copyright (c) 2005 the aforementioned authors. All rights
832 reserved. This program is free software; you can redistribute
833 it and/or modify it under the same terms as Perl itself.