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| − | 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. | + | 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. |
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| | OpenURLs are sent to the default index action of the [http://umlaut.rubyforge.org/api/files/app/controllers/resolve_controller_rb.html resolve controller]. | | OpenURLs are sent to the default index action of the [http://umlaut.rubyforge.org/api/files/app/controllers/resolve_controller_rb.html resolve controller]. |
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| | 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). | | 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). |
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| − | ==Setting up the Request and it's context== | + | ==Technical Overview Sections== |
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| − | ===OpenURL parsing and storing===
| + | # [[Request Setup and Environmental Context]] |
| − | | + | # [[ServiceResponse data structures and generation]] -- Includes guide to writing your own services. |
| − | 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.
| + | # [[View architecture and control flow]] |
| − | | + | # [[Background services]] -- control and view architectures for background services |
| − | 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 ActiveRecord classes--[http://umlaut.rubyforge.org/api/files/app/models/request_rb.html Request], to represent an incoming OpenURL request, and some constituent data in [http://umlaut.rubyforge.org/api/files/app/models/referent_rb.html Referrent], [http://umlaut.rubyforge.org/api/files/app/models/referent_value_rb.html Referent Value], and [http://umlaut.rubyforge.org/api/files/app/models/referrer_rb.html Referrer].
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| − | Once the OpenURL is parsed with the ropenurl library, the data is stored in internal Umlaut classes, which are generally used subsequently to deal with the request data.
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| − | A bit confusingly, Umlaut's own Request (an ActiveRecord which represents a parsed OpenURL request, and other persistent state related to Umlaut's handling of that OpenURL request) should not be confused with the Rails ActionController::Request class (which represents the complete details of the current 'raw' HTTP request, and is not stored persistently in the db).
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| − | 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.
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| − | ====Request caching/re-use====
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| − | The point of this re-use of Request objects 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. This also allows the user to click on various Umlaut functions and keep re-using the same Request. Again, the main reason this is important is to re-use already generated responses instead of re-generating them. This is also important for background service processing.
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| − | Cache matching for re-use is based on: Must be from the same session, must be from the same originating IP address, must have the same OpenURL elements (ie, same OpenURL parameters measured by a serialized version (Request#serialized_co_params)) stored in the 'params' attribute of Request.
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| − | Alternately, if the request ID is passed in (in query var "umlaut.request_id"), that is used instead of context object element matching. Umlaut often passes requestID internally, to make sure the same request is recovered. If request_id matches, sessions is not required to match--this is intentional to recover the request even if browser isn't returning cookies, thus not connecting to same session.
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| − | ===Building the service Collection: Institutions and Services===
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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).
