A module for handling JSON Web Tokens in eXist-db

see http://en.wikipedia.org/wiki/JSON_Web_Token

Provides a single library function:

declare module namespace jwt = 'http://max.terpstra.ca/ns/exist-jwt';
declare function jwt:get-verfied-claims(
	$jwt as xs:string,
	$key-callback as function(xs:string) as xs:string*,
	$audience as xs:string?
) as map(xs:string, item()*) external;

The $key-callback will be called with the token's issuer ID and should return a sequence of JSON Web Key values that may be used to verify the signature.

The return value is the JWT payload (aka "claims") translated into native XQuery data types. Objects are represented as map(xs:string, item()*), arrays as sequences, true/false as xs:boolean, strings as xs:string, and numbers as xs:decimal.