NAME¶
Webapp::retrieveFunction - Retrieve saved state
SYNOPSIS¶
b retrieveFunction( b() defn, String(String) retriever, String key
)
ARGUMENTS¶
defn The default function to call if the state key does not exist.
retriever A function that returns the encoded state when given the key
key The key to find the state
DESCRIPTION¶
In some circumstances you may need to store application state in an external
source, so that a user may save their session and return to it later. This
function lets you retrieve a saved state from an external source based on a
key. The function represented by the saved state is then executed. The
retrieval function should throw an Exception if it can't find the key, which
will cause the default function
defn to be executed instead.
Otherwise, it should, given the key, return the state string that was stored
using
Webapp.storeFunction (3kaya)
One use of this is to generate links to be sent via email, where the links
generated by Kaya containing the state data itself are too long to be
practical.
You should consider when writing the retrieval function whether the action of
retrieving the state should delete it from the persistent storage.
AUTHORS¶
Kaya standard library by Edwin Brady, Chris Morris and others
(kaya@kayalang.org). For further information see
http://kayalang.org/
LICENSE¶
The Kaya standard library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License (version
2.1 or any later version) as published by the Free Software Foundation.
Webapp.runHandler (3kaya)
Webapp.storeFunction (3kaya)