


Catalyst::PluginU:s:eSresCsoinotnr(i3bpu)ted PerlCDaotcaulmyesntt:a:tPiloungin::Session(3p)


NNAAMMEE
       Catalyst::Plugin::Session - Generic Session plugin - ties together
       server side storage and client side state required to maintain session
       data.

SSYYNNOOPPSSIISS
           # To get sessions to "just work", all you need to do is use these plugins:

           use Catalyst qw/
             Session
             Session::Store::FastMmap
             Session::State::Cookie
             /;

               # you can replace Store::FastMmap with Store::File - both have sensible
               # default configurations (see their docs for details)

               # more complicated backends are available for other scenarios (DBI storage,
               # etc)


           # after you've loaded the plugins you can save session data
           # For example, if you are writing a shopping cart, it could be implemented
           # like this:

           sub add_item : Local {
               my ( $self, $c ) = @_;

               my $item_id = $c->req->param("item");

               # $c->session is a hash ref, a bit like $c->stash
               # the difference is that it' preserved across requests

               push @{ $c->session->{items} }, $item_id;

               $c->forward("MyView");
           }

           sub display_items : Local {
               my ( $self, $c ) = @_;

               # values in $c->session are restored
               $c->stash->{items_to_display} =
                 [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ];

               $c->forward("MyView");
           }

DDEESSCCRRIIPPTTIIOONN
       The Session plugin is the base of two related parts of functionality
       required for session management in web applications.

       The first part, the State, is getting the browser to repeat back a
       session key, so that the web application can identify the client and



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Catalyst::PluginU:s:eSresCsoinotnr(i3bpu)ted PerlCDaotcaulmyesntt:a:tPiloungin::Session(3p)


       logically string several requests together into a session.

       The second part, the Store, deals with the actual storage of
       information about the client. This data is stored so that the it may be
       revived for every request made by the same client.

       This plugin links the two pieces together.

RREECCOOMMEENNDDEEDD BBAACCKKEENNDDSS
       Session::State::Cookie
           The only really sane way to do state is using cookies.

       Session::Store::File
           A portable backend, based on Cache::File.

       Session::Store::FastMmap
           A fast and flexible backend, based on Cache::FastMmap.

MMEETTHHOODDSS
       sessionid
           An accessor for the session ID value.

       session
           Returns a hash reference that might contain unserialized values
           from previous requests in the same session, and whose modified
           value will be saved for future requests.

           This method will automatically create a new session and session ID
           if none exists.

       session_expires
       session_expires $reset
           This method returns the time when the current session will expire,
           or 0 if there is no current session. If there is a session and it
           already expired, it will delete the session and return 0 as well.

           If the $reset parameter is true, and there is a session ID the
           expiry time will be reset to the current time plus the time to live
           (see "CONFIGURATION"). This is used when creating a new session.

       flash
           This is like Ruby on Rails' flash data structure. Think of it as a
           stash that lasts for longer than one request, letting you redirect
           instead of forward.

           The flash data will be cleaned up only on requests on which
           actually use $c->flash (thus allowing multiple redirections), and
           the policy is to delete all the keys which haven't changed since
           the flash data was loaded at the end of every request.

               sub moose : Local {
                   my ( $self, $c ) = @_;

                   $c->flash->{beans} = 10;



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Catalyst::PluginU:s:eSresCsoinotnr(i3bpu)ted PerlCDaotcaulmyesntt:a:tPiloungin::Session(3p)


                   $c->response->redirect( $c->uri_for("foo") );
               }

               sub foo : Local {
                   my ( $self, $c ) = @_;

                   my $value = $c->flash->{beans};

                   # ...

                   $c->response->redirect( $c->uri_for("bar") );
               }

               sub bar : Local {
                   my ( $self, $c ) = @_;

                   if ( exists $c->flash->{beans} ) { # false

                   }
               }

       clear_flash
           Zap all the keys in the flash regardless of their current state.

       keep_flash @keys
           If you wawnt to keep a flash key for the next request too, even if
           it hasn't changed, call "keep_flash" and pass in the keys as
           arguments.

       delete_session REASON
           This method is used to invalidate a session. It takes an optional
           parameter which will be saved in "session_delete_reason" if
           provided.

       session_delete_reason
           This accessor contains a string with the reason a session was
           deleted. Possible values include:

           +o   "address mismatch"

           +o   "session expired"

       session_expire_key $key, $ttl
           Mark a key to expire at a certain time (only useful when shorter
           than the expiry time for the whole session).

           For example:

               __PACKAGE__->config->{session}{expires} = 1000000000000; # forever

               # later

               $c->session_expire_key( __user => 3600 );




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Catalyst::PluginU:s:eSresCsoinotnr(i3bpu)ted PerlCDaotcaulmyesntt:a:tPiloungin::Session(3p)


           Will make the session data survive, but the user will still be
           logged out after an hour.

           Note that these values are not auto extended.

IINNTTEERRNNAALL MMEETTHHOODDSS
       setup
           This method is extended to also make calls to
           "check_session_plugin_requirements" and "setup_session".

       check_session_plugin_requirements
           This method ensures that a State and a Store plugin are also in use
           by the application.

       setup_session
           This method populates "$c->config->{session}" with the default
           values listed in "CONFIGURATION".

       prepare_action
           This methoid is extended.

           It's only effect is if the (off by default) "flash_to_stash"
           configuration parameter is on - then it will copy the contents of
           the flash to the stash at prepare time.

       finalize_headers
           This method is extended and will extend the expiry time before
           sending the response.

       finalize
           This method is extended and will call finalize_session after the
           other finalizes run.  Here we persist the session data if a session
           exists.

       initialize_session_data
           This method will initialize the internal structure of the session,
           and is called by the "session" method if appropriate.

       create_session_id
           Creates a new session id using "generate_session_id" if there is no
           session ID yet.

       validate_session_id SID
           Make sure a session ID is of the right format.

           This currently ensures that the session ID string is any amount of
           case insensitive hexadecimal characters.

       generate_session_id
           This method will return a string that can be used as a session ID.
           It is supposed to be a reasonably random string with enough bits to
           prevent collision. It basically takes "session_hash_seed" and
           hashes it using SHA-1, MD5 or SHA-256, depending on the
           availibility of these modules.



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Catalyst::PluginU:s:eSresCsoinotnr(i3bpu)ted PerlCDaotcaulmyesntt:a:tPiloungin::Session(3p)


       session_hash_seed
           This method is actually rather internal to generate_session_id, but
           should be overridable in case you want to provide more random data.

           Currently it returns a concatenated string which contains:

           +o   A counter

           +o   The current time

           +o   One value from "rand".

           +o   The stringified value of a newly allocated hash reference

           +o   The stringified value of the Catalyst context object

           In the hopes that those combined values are entropic enough for
           most uses. If this is not the case you can replace
           "session_hash_seed" with e.g.

               sub session_hash_seed {
                   open my $fh, "<", "/dev/random";
                   read $fh, my $bytes, 20;
                   close $fh;
                   return $bytes;
               }

           Or even more directly, replace "generate_session_id":

               sub generate_session_id {
                   open my $fh, "<", "/dev/random";
                   read $fh, my $bytes, 20;
                   close $fh;
                   return unpack("H*", $bytes);
               }

           Also have a look at Crypt::Random and the various openssl bindings
           - these modules provide APIs for cryptographically secure random
           data.

       finalize_session
           Clean up the session during "finalize".

           This clears the various accessors after saving to the store.

       dump_these
           See "dump_these" in Catalyst - ammends the session data structure
           to the list of dumped objects if session ID is defined.

       calculate_extended_session_expires
       calculate_initial_session_expires
       create_session_id_if_needed
       delete_session_id




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Catalyst::PluginU:s:eSresCsoinotnr(i3bpu)ted PerlCDaotcaulmyesntt:a:tPiloungin::Session(3p)


       extend_session_expires
       extend_session_id
       get_session_id
       reset_session_expires
       session_is_valid
       set_session_id

UUSSIINNGG SSEESSSSIIOONNSS DDUURRIINNGG PPRREEPPAARREE
       The earliest point in time at which you may use the session data is
       after Catalyst::Plugin::Session's "prepare_action" has finished.

       State plugins must set $c->session ID before "prepare_action", and
       during "prepare_action" Catalyst::Plugin::Session will actually load
       the data from the store.

               sub prepare_action {
                       my $c = shift;

                       # don't touch $c->session yet!

                       $c->NEXT::prepare_action( @_ );

                       $c->session;  # this is OK
                       $c->sessionid; # this is also OK
               }

CCOONNFFIIGGUURRAATTIIOONN
           $c->config->{session} = {
               expires => 1234,
           };

       All configuation parameters are provided in a hash reference under the
       "session" key in the configuration hash.

       expires
           The time-to-live of each session, expressed in seconds. Defaults to
           7200 (two hours).

       verify_address
           When true, "<$c-"request->address>> will be checked at prepare
           time. If it is not the same as the address that initiated the
           session, the session is deleted.

           Defaults to false.

       flash_to_stash
           This option makes it easier to have actions behave the same whether
           they were forwarded to or redirected to. On prepare time it copies
           the contents of "flash" (if any) to the stash.

SSPPEECCIIAALL KKEEYYSS
       The hash reference returned by "$c->session" contains several keys
       which are automatically set:




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Catalyst::PluginU:s:eSresCsoinotnr(i3bpu)ted PerlCDaotcaulmyesntt:a:tPiloungin::Session(3p)


       __expires
           This key no longer exists. Use "session_expires" instead.

       __updated
           The last time a session was saved to the store.

       __created
           The time when the session was first created.

       __address
           The value of "$c->request->address" at the time the session was
           created.  This value is only populated if "verify_address" is true
           in the configuration.

CCAAVVEEAATTSS
   RRoouunndd tthhee RRoobbiinn PPrrooxxiieess
       "verify_address" could make your site inaccessible to users who are
       behind load balanced proxies. Some ISPs may give a different IP to each
       request by the same client due to this type of proxying. If addresses
       are verified these users' sessions cannot persist.

       To let these users access your site you can either disable address
       verification as a whole, or provide a checkbox in the login dialog that
       tells the server that it's OK for the address of the client to change.
       When the server sees that this box is checked it should delete the
       "__address" sepcial key from the session hash when the hash is first
       created.

   RRaaccee CCoonnddiittiioonnss
       In this day and age where cleaning detergents and dutch football (not
       the american kind) teams roam the plains in great numbers, requests may
       happen simultaneously. This means that there is some risk of session
       data being overwritten, like this:

       1.  request a starts, request b starts, with the same session id

       2.  session data is loaded in request a

       3.  session data is loaded in request b

       4.  session data is changed in request a

       5.  request a finishes, session data is updated and written to store

       6.  request b finishes, session data is updated and written to store,
           overwriting changes by request a

       If this is a concern in your application, a soon to be developed
       locking solution is the only safe way to go. This will have a bigger
       overhead.

       For applications where any given user is only making one request at a
       time this plugin should be safe enough.




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Catalyst::PluginU:s:eSresCsoinotnr(i3bpu)ted PerlCDaotcaulmyesntt:a:tPiloungin::Session(3p)


AAUUTTHHOORRSS
       Andy Grundman
       Christian Hansen
       Yuval Kogman, "nothingmuch@woobling.org" (current maintainer)
       Sebastian Riedel

       And countless other contributers from #catalyst. Thanks guys!

CCOOPPYYRRIIGGHHTT && LLIICCEENNSSEE
               Copyright (c) 2005 the aforementioned authors. All rights
               reserved. This program is free software; you can redistribute
               it and/or modify it under the same terms as Perl itself.













































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