Add dataMimeType to RSocketRequestBuilder

Closes gh-23012

spring-messaging/spring-messaging.gradle

@@ -7,7 +7,7 @@ dependencyManagement {
 	}
 }
 
-def rsocketVersion = "0.12.2-RC3-SNAPSHOT"
+def rsocketVersion = "0.12.2-RC4-SNAPSHOT"
 
 dependencies {
 	compile(project(":spring-beans"))

spring-messaging/src/main/java/org/springframework/messaging/rsocket/DefaultRSocketRequesterBuilder.java

@@ -20,6 +20,7 @@ import java.net.URI;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Consumer;
+import java.util.stream.Stream;
 
 import io.rsocket.RSocketFactory;
 import io.rsocket.transport.ClientTransport;
@@ -28,6 +29,7 @@ import io.rsocket.transport.netty.client.WebsocketClientTransport;
 import reactor.core.publisher.Mono;
 
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 import org.springframework.util.MimeType;
 
 /**
@@ -39,6 +41,9 @@ import org.springframework.util.MimeType;
  */
 final class DefaultRSocketRequesterBuilder implements RSocketRequester.Builder {
 
+	@Nullable
+	private MimeType dataMimeType;
+
 	private List<Consumer<RSocketFactory.ClientRSocketFactory>> factoryConfigurers = new ArrayList<>();
 
 	@Nullable
@@ -47,6 +52,12 @@ final class DefaultRSocketRequesterBuilder implements RSocketRequester.Builder {
 	private List<Consumer<RSocketStrategies.Builder>> strategiesConfigurers = new ArrayList<>();
 
 
+	@Override
+	public RSocketRequester.Builder dataMimeType(MimeType mimeType) {
+		this.dataMimeType = mimeType;
+		return this;
+	}
+
 	@Override
 	public RSocketRequester.Builder rsocketFactory(Consumer<RSocketFactory.ClientRSocketFactory> configurer) {
 		this.factoryConfigurers.add(configurer);
@@ -81,17 +92,15 @@ final class DefaultRSocketRequesterBuilder implements RSocketRequester.Builder {
 	}
 
 	private Mono<RSocketRequester> doConnect(ClientTransport transport) {
-		RSocketStrategies rsocketStrategies = getRSocketStrategies();
-		RSocketFactory.ClientRSocketFactory rsocketFactory = RSocketFactory.connect();
 
-		// 1. Apply default settings
-		MimeType dataMimeType = getDefaultDataMimeType(rsocketStrategies);
-		if (dataMimeType != null) {
-			rsocketFactory.dataMimeType(dataMimeType.toString());
-		}
+		RSocketStrategies rsocketStrategies = getRSocketStrategies();
+		Assert.isTrue(!rsocketStrategies.encoders().isEmpty(), "No encoders");
+		Assert.isTrue(!rsocketStrategies.decoders().isEmpty(), "No decoders");
 
-		// 2. Application customizations
-		this.factoryConfigurers.forEach(c -> c.accept(rsocketFactory));
+		RSocketFactory.ClientRSocketFactory rsocketFactory = RSocketFactory.connect();
+		MimeType dataMimeType = getDataMimeType(rsocketStrategies);
+		rsocketFactory.dataMimeType(dataMimeType.toString());
+		this.factoryConfigurers.forEach(consumer -> consumer.accept(rsocketFactory));
 
 		return rsocketFactory.transport(transport).start()
 				.map(rsocket -> new DefaultRSocketRequester(rsocket, dataMimeType, rsocketStrategies));
@@ -109,18 +118,20 @@ final class DefaultRSocketRequesterBuilder implements RSocketRequester.Builder {
 		}
 	}
 
-	@Nullable
-	private MimeType getDefaultDataMimeType(RSocketStrategies strategies) {
-		return strategies.encoders().stream()
-				.flatMap(encoder -> encoder.getEncodableMimeTypes().stream())
-				.filter(MimeType::isConcrete)
-				.findFirst()
-				.orElseGet(() ->
+	private MimeType getDataMimeType(RSocketStrategies strategies) {
+		if (this.dataMimeType != null) {
+			return this.dataMimeType;
+		}
+		return Stream
+				.concat(
+						strategies.encoders().stream()
+								.flatMap(encoder -> encoder.getEncodableMimeTypes().stream()),
 						strategies.decoders().stream()
 								.flatMap(encoder -> encoder.getDecodableMimeTypes().stream())
-								.filter(MimeType::isConcrete)
-								.findFirst()
-								.orElse(null));
+				)
+				.filter(MimeType::isConcrete)
+				.findFirst()
+				.orElseThrow(() -> new IllegalArgumentException("Failed to select data MimeType to use."));
 	}
 
 }

spring-messaging/src/main/java/org/springframework/messaging/rsocket/RSocketRequester.java

@@ -106,11 +106,20 @@ public interface RSocketRequester {
 	 */
 	interface Builder {
 
+		/**
+		 * Configure the MimeType to use for payload data. This is set on the
+		 * {@code SETUP} frame for the whole connection.
+		 * <p>By default this is set to the first concrete MimeType supported
+		 * by the configured encoders and decoders.
+		 * @param mimeType the data MimeType to use
+		 */
+		RSocketRequester.Builder dataMimeType(MimeType mimeType);
+
 		/**
 		 * Configure the {@code ClientRSocketFactory}.
-		 * <p>Note there is typically no need to set a data MimeType explicitly.
-		 * By default a data MimeType is picked by taking the first concrete
-		 * MimeType supported by the configured encoders and decoders.
+		 * <p><strong>Note:</strong> Please, do not set the {@code dataMimeType}
+		 * directly on the underlying {@code RSocketFactory.ClientRSocketFactory},
+		 * and use {@link #dataMimeType(MimeType)} instead.
 		 * @param configurer the configurer to apply
 		 */
 		RSocketRequester.Builder rsocketFactory(Consumer<RSocketFactory.ClientRSocketFactory> configurer);

spring-messaging/src/test/java/org/springframework/messaging/rsocket/DefaultRSocketRequesterBuilderTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.messaging.rsocket;
 
+import java.lang.reflect.Field;
 import java.util.function.Consumer;
 
 import io.netty.buffer.ByteBuf;
@@ -28,6 +29,13 @@ import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
+import org.springframework.core.codec.CharSequenceEncoder;
+import org.springframework.core.codec.StringDecoder;
+import org.springframework.util.MimeType;
+import org.springframework.util.MimeTypeUtils;
+import org.springframework.util.ReflectionUtils;
+
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.BDDMockito.given;
@@ -67,9 +75,14 @@ public class DefaultRSocketRequesterBuilderTests {
 	@Test
 	@SuppressWarnings("unchecked")
 	public void shouldApplyCustomizations() {
+		RSocketStrategies strategies = RSocketStrategies.builder()
+				.encoder(CharSequenceEncoder.allMimeTypes())
+				.decoder(StringDecoder.allMimeTypes())
+				.build();
 		Consumer<RSocketFactory.ClientRSocketFactory> factoryConfigurer = mock(Consumer.class);
 		Consumer<RSocketStrategies.Builder> strategiesConfigurer = mock(Consumer.class);
 		RSocketRequester.builder()
+				.rsocketStrategies(strategies)
 				.rsocketFactory(factoryConfigurer)
 				.rsocketStrategies(strategiesConfigurer)
 				.connect(this.transport)
@@ -79,6 +92,25 @@ public class DefaultRSocketRequesterBuilderTests {
 		verify(strategiesConfigurer).accept(any(RSocketStrategies.Builder.class));
 	}
 
+	@Test
+	public void dataMimeType() throws NoSuchFieldException {
+		RSocketStrategies strategies = RSocketStrategies.builder()
+				.encoder(CharSequenceEncoder.allMimeTypes())
+				.decoder(StringDecoder.allMimeTypes())
+				.build();
+
+		RSocketRequester requester = RSocketRequester.builder()
+				.rsocketStrategies(strategies)
+				.dataMimeType(MimeTypeUtils.APPLICATION_JSON)
+				.connect(this.transport)
+				.block();
+
+		Field field = DefaultRSocketRequester.class.getDeclaredField("dataMimeType");
+		ReflectionUtils.makeAccessible(field);
+		MimeType dataMimeType = (MimeType) ReflectionUtils.getField(field, requester);
+		assertThat(dataMimeType).isEqualTo(MimeTypeUtils.APPLICATION_JSON);
+	}
+
 
 	static class MockConnection implements DuplexConnection {
 
@@ -99,7 +131,6 @@ public class DefaultRSocketRequesterBuilderTests {
 
 		@Override
 		public void dispose() {
-
 		}
 	}