Plack::Middleware::Session - Middleware for session management
use Plack::Builder;
my $app = sub {
my $env = shift;
my $session = $env->{'psgix.session'};
return [
200,
[ 'Content-Type' => 'text/plain' ],
[ "Hello, you've been here for ", $session->{counter}++, "th time!" ],
];
};
builder {
enable 'Session';
$app;
};
# Or, use the File store backend (great if you use multiprocess server)
# For more options, see perldoc Plack::Session::Store::File
builder {
enable 'Session', store => 'File';
$app;
};
This is a Plack Middleware component for session management. By default it will
use cookies to keep session state and store data in memory. This distribution
also comes with other state and store solutions. See perldoc for these
backends how to use them.
It should be noted that we store the current session as a hash
reference in the "psgix.session" key
inside the $env where you can access it as
needed.
NOTE: As of version 0.04 the session is stored in
"psgix.session" instead of
"plack.session".
- Plack::Session::State
- This will maintain session state by passing the session through the
request params. It does not do this automatically though, you are
responsible for passing the session param.
- Plack::Session::State::Cookie
- This will maintain session state using browser cookies.
- Plack::Session::Store
- This is your basic in-memory session data store. It is volatile storage
and not recommended for multiprocessing environments. However it is very
useful for development and testing.
- Plack::Session::Store::File
- This will persist session data in a file. By default it uses Storable but
it can be configured to have a custom serializer and deserializer.
- Plack::Session::Store::Cache
- This will persist session data using the Cache interface.
- Plack::Session::Store::Null
- Sometimes you don't care about storing session data, in that case you can
use this noop module.
The following are options that can be passed to this module.
- state
- This is expected to be an instance of Plack::Session::State or an object
that implements the same interface. If no option is provided the default
Plack::Session::State::Cookie will be used.
- store
- This is expected to be an instance of Plack::Session::Store or an object
that implements the same interface. If no option is provided the default
Plack::Session::Store will be used.
It should be noted that this default is an in-memory volatile
store is only suitable for development (or single process servers). For
a more robust solution see Plack::Session::Store::File or
Plack::Session::Store::Cache.
In addition to providing a "psgix.session" key
in $env for persistent session information, this
module also provides a
"psgix.session.options" key which can be
used to control the behavior of the module per-request. The following sub-keys
exist:
- change_id
- If set to a true value, forces the session identifier to change. This
should always be done after logging in, to prevent session fixation
attacks from subdomains; see
<http://en.wikipedia.org/wiki/Session_fixation#Attacks_using_cross-subdomain_cooking>
- expire
- If set to a true value, expunges the session from the store, and clears
the state in the client.
- no_store
- If set to a true value, no changes made to the session in this request
will be saved to the store. Either "expire" and
/change_id take precedence over this, as both need to update the
session store.
- late_store
- If set to a true value, the session will be saved at the end of the
request, after all data has been sent to the client -- this may be
required if streaming responses attempt to alter the session after the
header has already been sent to the client. Note, however, that it
introduces a possible race condition, where the server attempts to store
the updated session before the client makes the next request. For
redirects, or other responses on which the client needs do minimal
processing before making a second request, this race is quite possible to
win -- causing the second request to obtain stale session data.
- id
- This key contains the session identifier of the session. It should be
considered read-only; to generate a new identifier, use
"change_id".
All complex software has bugs lurking in it, and this module is no exception. If
you find a bug please either email me, or add the bug to cpan-RT.
Tatsuhiko Miyagawa
Stevan Little <stevan.little@iinteractive.com>
Copyright 2009, 2010 Infinity Interactive, Inc.
<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.