Interface RequestBodyMarshaler

Functional Interface:
This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface public interface RequestBodyMarshaler
Contract for converting request body bytes into a corresponding Java type.

For example, if your Resource Methods expect JSON request bodies like this (note the RequestBody annotation): 

 @POST("/find-biggest")
public Integer findBiggest(@RequestBody List<Integer> numbers) {
  // JSON request body [1,2,3] results in 3 being returned
  return Collections.max(numbers);
}

You might implement a RequestBodyMarshaler to accept JSON like this: 

 SokletConfig config = SokletConfig.withServer(
  Server.withPort(8080).build()
).requestBodyMarshaler(new RequestBodyMarshaler() {
  // This example uses Google's GSON
  static final Gson GSON = new Gson();

  @Nonnull
  @Override
  public Optional<Object> marshalRequestBody(
    @Nonnull Request request,
    @Nonnull ResourceMethod resourceMethod,
    @Nonnull Parameter parameter,
    @Nonnull Type requestBodyType
  ) {
    // Let GSON turn the request body into an instance
    // of the specified type.
    //
    // Note that this method has access to all runtime information
    // about the request, which provides the opportunity to, for example,
    // examine annotations on the method/parameter which might
    // inform custom marshaling strategies.
    return Optional.of(GSON.fromJson(
      request.getBodyAsString().get(),
      requestBodyType
    ));
  }
}).build();

A standard threadsafe implementation can be acquired via the withValueConverterRegistry(ValueConverterRegistry) factory method.

See https://www.soklet.com/docs/request-handling#request-body for detailed documentation.

Author:
Mark Allen

  • Method Details

    • marshalRequestBody

      @Nonnull Optional<Object> marshalRequestBody(@Nonnull Request request, @Nonnull ResourceMethod resourceMethod, @Nonnull Parameter parameter, @Nonnull Type requestBodyType)
      Given a request, the Resource Method that will handle it, and a RequestBody-annotated parameter + its type, convert the request body bytes into an instance of type requestBodyType.

      This instance will be injected by Soklet when it invokes the Resource Method to handle the request.

      Parameters:
      request - the request whose body should be converted into a Java type
      resourceMethod - the Resource Method that is configured to handle the request
      parameter - the Resource Method parameter into which the returned instance will be injected
      requestBodyType - the type of the Resource Method parameter (provided for convenience)
      Returns:
      the Java instance that corresponds to the request body bytes suitable for assignment to the Resource Method parameter, or Optional.empty() if no instance should be marshaled

    • withValueConverterRegistry

      @Nonnull static RequestBodyMarshaler withValueConverterRegistry(@Nonnull ValueConverterRegistry valueConverterRegistry)
      Acquires a threadsafe RequestBodyMarshaler implementation which converts request body data using the provided ValueConverterRegistry.

      You will likely want to provide your own implementation of RequestBodyMarshaler instead if your system accepts, for example, JSON request bodies.

      Callers should not rely on reference identity; this method may return a new or cached instance.

      Parameters:
      valueConverterRegistry - a registry of converters that can transform String types to arbitrary Java types
      Returns:
      a default RequestBodyMarshaler backed by the given ValueConverterRegistry