Umlaut Technical Overview

To give you an overview of the technical architecture of umlaut, we will go through a typical Resolve request, identifying all the classes involved, and pointing to their api doc if possible.

OpenURLs are sent to the default index action of the resolve controller.

In the resolve controller, a before filter method called init_processing is run to parse the OpenURL and set up the Umlaut request (or retrieve an existing request).

OpenURL parsing and initial action

In understanding Umlaut, it's helpful to understand a bit about the nature of an OpenURL, including that an OpenURL is composed of several entities or groupings of metadata. Jeff Young's Q6 blog includes one good explanation of the six OpenURL entities.

Two sets of classes are involved in dealing with OpenURLs in Umlaut. The ropenurl library is generally used to parse OpenURLs. However, Umlaut serializes OpenURLs to it's own classes--Request, to represent an incoming OpenURL request, and some constituent data in Referrent, Referent Value, and Referrer.