How to Add an API v2 Route
Write SPARQL templates
Add any SPARQL templates you need to src/main/twirl/queries/sparql/v2,
using the Twirl template
engine.
Write Responder Request and Response Messages
Add a file to the org.knora.webapi.messages.v2.responder
package, containing case classes for your responder's request and
response messages. Add a trait that the responder's request messages
extend. Each request message type should contain a UserADM.
Request and response messages should be designed following the patterns described
in JSON-LD Parsing and Formatting. Each responder's
request messages should extend a responder-specific trait, so that
ResponderManager will know which responder to route those messages to.
Write a Responder
Write a Pekko actor class that extends org.knora.webapi.responders.Responder,
and add it to the org.knora.webapi.responders.v2 package.
Give your responder a receive(msg: YourCustomType) method that handles each of your
request message types by generating a Future containing a response message.
Add the path of your responder to the org.knora.webapi.responders package object,
and add code to ResponderManager to instantiate the new responder. Then add a case to
the receive method in ResponderManager, to match messages that extend your request
message trait, and pass them them to that responder's receive method.
The responder's resulting Future must be passed to the ActorUtil.future2Message.
See Futures with Pekko and
Error Handling for details.
Write a Route
Add a class to the org.knora.webapi.routing.v2 package for your
route, using the Pekko HTTP Routing DSL.
See the routes in that package for examples. Typically, each route
route will construct a responder request message and pass it to
RouteUtilV2.runRdfRouteWithFuture to handle the request.
Finally, add your route's knoraApiPath function to the apiRoutes member
variable in KnoraService. Any exception thrown inside the route will
be handled by the KnoraExceptionHandler, so that the correct client
response (including the HTTP status code) will be returned.