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.

RELATED

       Webapp.runHandler (3kaya)
       Webapp.storeFunction (3kaya)

Kaya                                                July 2013                     Webapp.retrieveFunction(3kaya)