safeDecodeRequest workaround

SafeDecodeRequestDirectives.java

import akka.http.javadsl.model.HttpEntities;
import akka.http.javadsl.model.HttpEntity;
import akka.http.javadsl.model.RequestEntity;
import akka.http.javadsl.server.Route;

import java.util.function.Supplier;

import static akka.http.javadsl.server.Directives.decodeRequest;
import static akka.http.javadsl.server.Directives.mapRequest;
import static akka.http.javadsl.server.Directives.withSizeLimit;

public class SafeDecodeRequestDirectives {
    public static Route safeDecodeRequest(long maxBytes, Supplier<Route> inner) {
        return
                decodeRequest(() ->
                        mapRequest(req -> req.withEntity(chunkedWithLimit(req.entity())), () ->
                                withSizeLimit(maxBytes, inner)
                        )
                );
    }
    private static RequestEntity chunkedWithLimit(RequestEntity entity) {
        if (entity.isChunked())
            return
                    HttpEntities.createChunked(
                            entity.getContentType(),
                            akka.http.scaladsl.model.HttpEntity.limitableByteSource(((HttpEntity.Chunked)entity).getDataBytes().asScala()).asJava()
                    );
        else
            return entity;
    }
}

SafeDecodeRequestDirectives.scala

import akka.http.scaladsl.model.HttpEntity
import akka.http.scaladsl.server.Directives.decodeRequest
import akka.http.scaladsl.server.Directives.mapRequest
import akka.http.scaladsl.server.Directives.withSizeLimit

object SafeDecodeRequestDirectives {
  def safeDecodeRequest(maxBytes: Long): Directive0 =
    decodeRequest & mapRequest(_.mapEntity {
      // decodeRequest will create chunked entity when it decodes something. Add the missing limit support.
      case c: HttpEntity.Chunked ⇒ c.copy(chunks = HttpEntity.limitableChunkSource(c.chunks))
      case e                     ⇒ e
    }) & withSizeLimit(maxBytes)
}