What is an Active URI?

An Active URI addresses a resource which is explicitly computed by the application of a function to a set of other resources.

An Active URI is a URI which contains multiple named inner URIs. It is 100% compatible with the IETF [RFC2396,RFC1738] URI specification and so can be used everywhere a URI can be used. A compound URI has the form

{scheme}:{type}+{arg}@{value}+{arg}@{value}+....

Where {scheme} is any valid URI scheme. {type} is an application specific type declaration and may itself be an escaped URI. {arg} is an argument name. {value} is an escaped inner URI.

Active URIs can be used to nest URI's to arbitrary depth provided all inner URI's are correctly escaped. Therefore a compound URI can hold another compound URI as an argument value.

Active URI Manipulation

In order to be valid a URI a compound URI must be carefully escaped. The layer1 module provides a utility class org.ten60.netkernel.layer1.util.CompoundURIdentifier which can be used to add, remove and query the parts of a compound URI and which performs all necessary escaping.

Using Active URIs to address Accessors

Active URIs are the primary addressing scheme for invoking Active accessors. An accessor requests arguments can be be either by reference or by value. It queries the compound URI for a set of named arguments to obtain the URI of an argument.

The convention for invoking an accessor is to use the active: scheme.