A marker trait denoting a class that can act as a default com.twitter.finatra.http.marshalling.MessageBodyWriter for the HTTP server.

This default is invoked by either the com.twitter.finatra.http.internal.CallbackConverter (by invoking the com.twitter.finatra.http.response.ResponseBuilder) or com.twitter.finatra.http.response.ResponseBuilder#write directly to return a suitable response for a given return type.

The framework binds com.twitter.finatra.http.internal.marshalling.DefaultMessageBodyWriterImpl as an overridable implementation via the com.twitter.finatra.http.modules.MessageBodyModule. To override this implementation, provide a customized com.twitter.inject.TwitterModule by overriding com.twitter.finatra.http.HttpServer.messageBodyModule, e.g.,

class MyServer extends HttpServer {
   ...
   override val messageBodyModule = MyCustomMessageBodyModule
}

The framework default will attempt to convert the outgoing type T to a JSON response using the server's configured com.twitter.util.jackson.ScalaObjectMapper.

The com.twitter.finatra.http.marshalling.DefaultMessageBodyWriter trait differs from the com.twitter.finatra.http.marshalling.MessageBodyWriter trait in that the default is not parameterized to a specific type but instead defines a generic write[T] function which can generate a response from a given type T.