Dancer::Session(3) User Contributed Perl Documentation Dancer::Session(3)NAMEDancer::Session - session engine for the Dancer framework
DESCRIPTION
This module provides support for server-side sessions for the Dancer
web framework. The session is accessible to the user via an abstraction
layer implemented by the Dancer::Session class.
USAGE
Configuration
The session engine must be first enabled in the environment settings,
this can be done like the following:
In the application code:
# enabling the YAML-file-based session engine
set session => 'YAML';
Or in config.yml or environments/$env.yml
session: "YAML"
By default sessions are disabled, you must enable them before using it.
If the session engine is disabled, any Dancer::Session call will throw
an exception.
See "Configuration" in Dancer::Session::Abstract for more configuration
options.
Route Handlers
When enabled, the session engine can be used in a route handler with
the keyword session. This keyword allows you to store/retrieve values
from the session by name.
Storing a value into the session:
session foo => 'bar';
Retrieving that value later:
my $foo = session 'foo';
You can either look for an existing item in the session storage or
modify one. Here is a simple example of two route handlers that
implement basic "/login" and "/home" actions using the session engine.
post '/login' => sub {
# look for params and authenticate the user
# ...
if ($user) {
session user_id => $user->id;
}
};
get '/home' => sub {
# if a user is present in the session, let him go, otherwise redirect to
# /login
if (not session('user_id')) {
redirect '/login';
a
};
Of course, you probably don't want to have to duplicate the code to
check whether the user is logged in for each route handler; there's an
example in the Dancer::Cookbook showing how to use a before filter to
check whether the user is logged in before all requests, and redirect
to a login page if not.
SUPPORTED ENGINES
Dancer has a modular session engine that makes implementing new session
backends pretty easy. If you'd like to write your own, feel free to
take a look at Dancer::Session::Abstract.
The following engines are supported out-of-the-box (shipped with the
core Dancer distribution):
Dancer::Session::YAML
A YAML file-based session backend, pretty convenient for
development purposes, but maybe not the best for production needs.
Dancer::Session::Simple
A very simple session backend, holding all session data in memory.
This means that sessions are volatile, and no longer exist when the
process exits. This module is likely to be most useful for testing
purposes, and of little use for production.
Additionally, many more session engines are available from CPAN,
including:
Dancer::Session::Memcached
Session are stored in Memcached servers. This is good for
production matters and is a good way to use a fast, distributed
session storage. If you may be scaling up to add additional
servers later, this will be a good choice.
Dancer::Session::Cookie
This module implements a session engine for sessions stored
entirely inside encrypted cookies (this engine doesn't use a
server-side storage).
Dancer::Session::Storable
This backend stores sessions on disc using Storable, which offers
solid performance and reliable serialisation of various data
structures.
Dancer::Session::MongoDB
A backend to store sessions using MongoDB
Dancer::Session::KiokuDB
A backend to store sessions using KiokuDB
Dancer::Session::PSGI
Let Plack::Middleware::Session handle sessions; may be useful to
share sessions between a Dancer app and other Plack-based apps.
DEPENDENCYDancer::Session may depend on third-party modules, depending on the
session engine used. See the session engine module for details.
AUTHORS
This module has been written by Alexis Sukrieh. See the AUTHORS file
that comes with this distribution for details.
LICENSE
This module is free software and is released under the same terms as
Perl itself.
SEE ALSO
See Dancer for details about the complete framework.
perl v5.14.1 2011-06-15 Dancer::Session(3)