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Kopflos request pipeline

Incoming Request
  │
  └─▶ Kopflos handler
             │
   4**/5** ◀─┴─▶ Resource Shape Lookup
                   │
         4**/5** ◀─┴─▶ Resource Loader Lookup
                         │
               4**/5** ◀─┴─▶ Load Resource
                               │
                         4** ◀─┴─▶ Authorization
                                     │
                               400 ◀─┴─▶ Validation
                                           │
                                 4**/5** ◀─┴─▶ (User handler)
                                                 │
                                                 └─▶ Reply

Incoming request​

Incoming request is handled by the server library, such as express or fastify and then forwarded to Kopflos.

Kopflos handler​

Kopflos handler is the main entry point for all incoming requests. It is responsible for orchestrating the request pipeline.

Resource Shape Lookup​

Resource Shape Lookup executes SPARQL against the default query endpoint to find the shape targeting the requested resource.

tip

See also: How to Select which resources should be served by the API

Resource Loader Lookup + Load Resource​

When the Resource Shape is found, a resource loader is selected based from kopflos:resourceLoader property, going bottom-up from the Resource/Property Shape to the shared kopflos:Config resource.

It is used to load the requested resource's Core Representation.

warning

By default, a loader which returns the resource's own graph is used.

Authorization​

Not implemented yet.

Validation​

Not implemented yet.

User handler​

Finally, the handler is executed. If no handler is defined, and the request method is a GET, the resource's Core Representation is returned.

The result of the handler is forwarded back to the server library to be sent as a response.