Merge branch '3.1.x'

pom.xml

@@ -57,6 +57,7 @@
 		<spring-cloud-circuitbreaker.version>3.0.1-SNAPSHOT</spring-cloud-circuitbreaker.version>
 		<spring-cloud-commons.version>4.0.1-SNAPSHOT</spring-cloud-commons.version>
 		<testcontainers.version>1.17.3</testcontainers.version>
+		<kotlin-maven-plugin.version>1.6.21</kotlin-maven-plugin.version>
 	</properties>
 
 	<dependencyManagement>

spring-cloud-gateway-sample/pom.xml

@@ -95,6 +95,7 @@
 			<plugin>
 				<groupId>org.jetbrains.kotlin</groupId>
 				<artifactId>kotlin-maven-plugin</artifactId>
+				<version>${kotlin-maven-plugin.version}</version>
 				<configuration>
 					<args>
 						<arg>-Xjsr305=strict</arg>

spring-cloud-gateway-server/pom.xml

@@ -230,6 +230,7 @@
 				<!-- Based on instructions here - https://kotlinlang.org/docs/reference/using-maven.html -->
 				<artifactId>kotlin-maven-plugin</artifactId>
 				<groupId>org.jetbrains.kotlin</groupId>
+				<version>${kotlin-maven-plugin.version}</version>
 				<configuration>
 					<jvmTarget>17</jvmTarget>
 				</configuration>

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/support/ServerWebExchangeUtils.java

@@ -369,14 +369,19 @@ public final class ServerWebExchangeUtils {
 			if (log.isTraceEnabled()) {
 				log.trace("retaining body in exchange attribute");
 			}
-			exchange.getAttributes().put(CACHED_REQUEST_BODY_ATTR, dataBuffer);
+
+			Object cachedDataBuffer = exchange.getAttribute(CACHED_REQUEST_BODY_ATTR);
+			// don't cache if body is already cached
+			if (!(cachedDataBuffer instanceof DataBuffer)) {
+				exchange.getAttributes().put(CACHED_REQUEST_BODY_ATTR, dataBuffer);
+			}
 		}
 
 		ServerHttpRequest decorator = new ServerHttpRequestDecorator(exchange.getRequest()) {
 			@Override
 			public Flux<DataBuffer> getBody() {
 				return Mono.fromSupplier(() -> {
-					if (exchange.getAttributeOrDefault(CACHED_REQUEST_BODY_ATTR, null) == null) {
+					if (exchange.getAttribute(CACHED_REQUEST_BODY_ATTR) == null) {
 						// probably == downstream closed or no body
 						return null;
 					}

spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/support/ServerWebExchangeUtilsTests.java

@@ -16,14 +16,17 @@
 
 package org.springframework.cloud.gateway.support;
 
+import java.nio.charset.StandardCharsets;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
-import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
+import org.assertj.core.api.Assertions;
+import org.junit.Test;
 
+import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DefaultDataBuffer;
+import org.springframework.http.HttpMethod;
 import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
 import org.springframework.mock.web.server.MockServerWebExchange;
 import org.springframework.web.reactive.function.server.HandlerStrategies;
@@ -70,8 +73,42 @@ public class ServerWebExchangeUtilsTests {
 				.block();
 	}
 
+	@Test
+	public void duplicatedCachingDataBufferHandling() {
+		MockServerWebExchange exchange = mockExchange(HttpMethod.POST, Collections.emptyMap());
+		DataBuffer dataBufferBeforeCaching = exchange.getResponse().bufferFactory()
+				.wrap("Cached buffer".getBytes(StandardCharsets.UTF_8));
+		exchange.getAttributes().put(CACHED_REQUEST_BODY_ATTR, dataBufferBeforeCaching);
+
+		ServerWebExchangeUtils
+				.cacheRequestBodyAndRequest(exchange,
+						(serverHttpRequest) -> ServerRequest
+								.create(exchange.mutate().request(serverHttpRequest).build(),
+										HandlerStrategies.withDefaults().messageReaders())
+								.bodyToMono(DefaultDataBuffer.class))
+				.block();
+
+		DataBuffer dataBufferAfterCached = exchange.getAttribute(CACHED_REQUEST_BODY_ATTR);
+
+		Assertions.assertThat(dataBufferBeforeCaching).isEqualTo(dataBufferAfterCached);
+	}
+
 	private MockServerWebExchange mockExchange(Map<String, String> vars) {
-		MockServerHttpRequest request = MockServerHttpRequest.get("/get").build();
+		return mockExchange(HttpMethod.GET, vars);
+	}
+
+	private MockServerWebExchange mockExchange(HttpMethod method, Map<String, String> vars) {
+
+		MockServerHttpRequest request = null;
+		if (HttpMethod.GET.equals(method)) {
+			request = MockServerHttpRequest.get("/get").build();
+		}
+		else if (HttpMethod.POST.equals(method)) {
+			request = MockServerHttpRequest.post("/post").body("post body");
+		}
+
+		Assertions.assertThat(request).as("Method was not one of GET or POST").isNotNull();
+
 		MockServerWebExchange exchange = MockServerWebExchange.from(request);
 		ServerWebExchangeUtils.putUriTemplateVariables(exchange, vars);
 		return exchange;