Fixed DataBufferLimitException in WebFlux result in 413 instead of 500

spring-web/src/main/java/org/springframework/web/server/ServerWebInputTooLargeException.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.server;
+
+
+import org.springframework.http.HttpStatus;
+import org.springframework.lang.Nullable;
+
+/**
+ * Exception for errors that fit response status 413 (payload too large) for use in
+ * Spring Web applications.
+ *
+ * @author Kim Bosung
+ * @since 6.2
+ */
+@SuppressWarnings("serial")
+public class ServerWebInputTooLargeException extends ResponseStatusException {
+
+	public ServerWebInputTooLargeException(@Nullable Throwable cause) {
+		super(HttpStatus.PAYLOAD_TOO_LARGE, null, cause);
+	}
+
+}

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractMessageReaderArgumentResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -34,6 +34,7 @@
 import org.springframework.core.codec.DecodingException;
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferLimitException;
 import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
@@ -54,6 +55,7 @@
 import org.springframework.web.server.ResponseStatusException;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.ServerWebInputException;
+import org.springframework.web.server.ServerWebInputTooLargeException;
 import org.springframework.web.server.UnsupportedMediaTypeStatusException;
 
 /**
@@ -64,6 +66,7 @@
  * {@linkplain org.springframework.validation.annotation.ValidationAnnotationUtils#determineValidationHints
  * annotations that trigger validation}. Validation failure results in a
  * {@link ServerWebInputException}.
+ * {@link ServerWebInputTooLargeException}.
  *
  * @author Rossen Stoyanchev
  * @author Sebastien Deleuze
@@ -233,8 +236,15 @@ protected Mono<Object> readBody(MethodParameter bodyParam, @Nullable MethodParam
 	}
 
 	private Throwable handleReadError(MethodParameter parameter, Throwable ex) {
-		return (ex instanceof DecodingException ?
-				new ServerWebInputException("Failed to read HTTP message", parameter, ex) : ex);
+		if (ex instanceof DataBufferLimitException) {
+			return new ServerWebInputTooLargeException(ex);
+		}
+
+		if (ex instanceof DecodingException) {
+			return new ServerWebInputException("Failed to read HTTP message", parameter, ex);
+		}
+
+		return ex;
 	}
 
 	private ServerWebInputException handleMissingBody(MethodParameter parameter) {

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/MessageReaderArgumentResolverTests.java

@@ -54,6 +54,7 @@
 import org.springframework.web.reactive.BindingContext;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.ServerWebInputException;
+import org.springframework.web.server.ServerWebInputTooLargeException;
 import org.springframework.web.server.UnsupportedMediaTypeStatusException;
 import org.springframework.web.testfixture.http.server.reactive.MockServerHttpRequest;
 import org.springframework.web.testfixture.method.ResolvableMethod;
@@ -112,6 +113,24 @@ public void emptyBody() {
 		StepVerifier.create(result).expectError(ServerWebInputException.class).verify();
 	}
 
+	@Test @SuppressWarnings("unchecked")
+	public void tooLargeBody() {
+		StringBuilder bodyBuilder = new StringBuilder();
+		while (bodyBuilder.toString().getBytes().length < 256 * 1024) {
+			bodyBuilder.append("The default maximum input length is 256kb.");
+		}
+		String body = "{\"bar\":\"BARBAR\",\"foo\":\"" + bodyBuilder + "\"}";
+
+		MockServerHttpRequest request = post("/path").contentType(MediaType.APPLICATION_JSON).body(body);
+		ServerWebExchange exchange = MockServerWebExchange.from(request);
+		ResolvableType type = forClassWithGenerics(Mono.class, TestBean.class);
+		MethodParameter param = this.testMethod.arg(type);
+		Mono<TestBean> result = (Mono<TestBean>) this.resolver.readBody(
+				param, true, this.bindingContext, exchange).block();
+
+		StepVerifier.create(result).expectError(ServerWebInputTooLargeException.class).verify();
+	}
+
 	@Test
 	void monoTestBean() {
 		String body = "{\"bar\":\"BARBAR\",\"foo\":\"FOOFOO\"}";