Fix requestChannel to not drop first payload (#398)

Author: yschimke

rsocket-core/src/main/java/io/rsocket/RSocketServer.java

@@ -16,13 +16,13 @@
 
 package io.rsocket;
 
+import static io.rsocket.Frame.Request.initialRequestN;
 import static io.rsocket.frame.FrameHeaderFlyweight.FLAGS_C;
 import static io.rsocket.frame.FrameHeaderFlyweight.FLAGS_M;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.util.collection.IntObjectHashMap;
-import io.rsocket.Frame.Request;
 import io.rsocket.exceptions.ApplicationException;
 import io.rsocket.internal.LimitableRequestPublisher;
 import io.rsocket.util.PayloadImpl;
@@ -157,7 +157,8 @@ private Mono<Void> handleFrame(Frame frame) {
         case REQUEST_N:
           return handleRequestN(streamId, frame);
         case REQUEST_STREAM:
-          return handleStream(streamId, requestStream(new PayloadImpl(frame)), frame);
+          return handleStream(
+              streamId, requestStream(new PayloadImpl(frame)), initialRequestN(frame));
         case REQUEST_CHANNEL:
           return handleChannel(streamId, frame);
         case PAYLOAD:
@@ -235,8 +236,7 @@ private Mono<Void> handleRequestResponse(int streamId, Mono<Payload> response) {
     return responseFrame.flatMap(connection::sendOne);
   }
 
-  private Mono<Void> handleStream(int streamId, Flux<Payload> response, Frame firstFrame) {
-    int initialRequestN = Request.initialRequestN(firstFrame);
+  private Mono<Void> handleStream(int streamId, Flux<Payload> response, int initialRequestN) {
     Flux<Frame> responseFrames =
         response
             .map(payload -> Frame.PayloadFrame.from(streamId, FrameType.NEXT, payload))
@@ -287,7 +287,11 @@ private Mono<Void> handleChannel(int streamId, Frame firstFrame) {
                 })
             .doFinally(signalType -> removeChannelProcessor(streamId));
 
-    return handleStream(streamId, requestChannel(payloads), firstFrame);
+    // not chained, as the payload should be enqueued in the Unicast processor before this method returns
+    // and any later payload can be processed
+    frames.onNext(new PayloadImpl(firstFrame));
+
+    return handleStream(streamId, requestChannel(payloads), initialRequestN(firstFrame));
   }
 
   private Mono<Void> handleKeepAliveFrame(Frame frame) {

rsocket-test/src/main/java/io/rsocket/test/BaseClientServerTest.java

@@ -20,6 +20,7 @@
 
 import io.rsocket.Payload;
 import io.rsocket.util.PayloadImpl;
+import org.junit.Ignore;
 import org.junit.Rule;
 import org.junit.Test;
 import reactor.core.publisher.Flux;
@@ -79,7 +80,7 @@ public void testRequestResponse10() {
     assertEquals(10, outputCount);
   }
 
-  private PayloadImpl testPayload(int metadataPresent) {
+  private Payload testPayload(int metadataPresent) {
     String metadata;
     switch (metadataPresent % 5) {
       case 0:
@@ -164,4 +165,35 @@ public void testRequestStreamWithDelayedRequestN() {
 
     assertEquals(10, ts.count());
   }
+
+  @Test(timeout = 10000)
+  @Ignore
+  public void testChannel0() {
+    Flux<Payload> publisher = setup.getRSocket().requestChannel(Flux.empty());
+
+    long count = publisher.count().block();
+
+    assertEquals(0, count);
+  }
+
+  @Test(timeout = 10000)
+  public void testChannel1() {
+    Flux<Payload> publisher = setup.getRSocket().requestChannel(Flux.just(testPayload(0)));
+
+    long count = publisher.count().block();
+
+    assertEquals(1, count);
+  }
+
+  @Test(timeout = 10000)
+  public void testChannel3() {
+    Flux<Payload> publisher =
+        setup
+            .getRSocket()
+            .requestChannel(Flux.just(testPayload(0), testPayload(1), testPayload(2)));
+
+    long count = publisher.count().block();
+
+    assertEquals(3, count);
+  }
 }

rsocket-test/src/main/java/io/rsocket/test/TestRSocket.java

@@ -19,6 +19,7 @@
 import io.rsocket.AbstractRSocket;
 import io.rsocket.Payload;
 import io.rsocket.util.PayloadImpl;
+import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
@@ -43,4 +44,10 @@ public Mono<Void> metadataPush(Payload payload) {
   public Mono<Void> fireAndForget(Payload payload) {
     return Mono.empty();
   }
+
+  @Override
+  public Flux<Payload> requestChannel(Publisher<Payload> payloads) {
+    // TODO is defensive copy neccesary?
+    return Flux.from(payloads).map(p -> new PayloadImpl(p.getDataUtf8(), p.getMetadataUtf8()));
+  }
 }