Changes

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

==Setting up the Request and it's contextTechnical Overview Sections==

===OpenURL parsing and storing=== 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 # [http://q6.oclc.org/2006/08/welcome_1.html 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--[http://umlaut.rubyforge.org/api/files/app/models/request_rb.html Request], to represent an incoming OpenURL request, Setup and some constituent data in [http://umlaut.rubyforge.org/api/files/app/models/referent_rb.html ReferrentEnvironmental Context], ]# [http://umlaut.rubyforge.org/api/files/app/models/referent_value_rb.html Referent Value], [ServiceResponse data structures and [http://umlaut.rubyforge.org/api/files/app/models/referrer_rb.html Referrergeneration]. A bit confusingly, Umlaut's ] -- Includes guide to writing your own Request (which represents a parsed OpenURL request) should not be confused with the Rails ActionController::Request class which represents the complete details of an 'raw' HTTP requestservices.  So the first thing the resolve action does is pass the incoming HTTP request details to the Umlaut Request#new_request method, which will ''''either'''' create a new Request, or recover an already created Request from the db--in either case return a Request matching the OpenURL. [[View architecture and control flow]] ====Request caching==== The point of this recovery is that if the user presses the browser reload button, the app should be connected with the same already created request--allowing the same already generated responses to be used, among other things. Cache matching is based on: Must be from the same session, must be from the same originating IP address, must have the same OpenURL parameters (same OpenURL parameters measured by a serialized version (Request#serialized_co_params) of recognized openurl paramters stored in the 'params' attribute.  Alternately, if the request ID is passed in (in query var "umlaut.request_id"), that is used instead of context object matching. Umlaut often passes requestID internally, to make sure the same request is recovered. If request_id matches, sessions is not required to match[[Background services]] --this is intentional to recover the request even if browser isn't returning cookies, thus not connecting to same session. ===Building the service Collection: Institutions control and Services===view architectures for background services