Clean multipart up only when data is read

This commit ensures that any storage used for multipart handling only gets cleaned up if multipart data is actually retrieved via ServerWebExchange::getMultipartData. Closes spring-projectsgh-30590
mdeinum · Jun 29, 2023 · 5b3ecb0 · 5b3ecb0
1 parent ff5cb6d
commit 5b3ecb0
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Showing 2 changed files with 26 additions and 15 deletions.
diff --git a/spring-web/src/main/java/org/springframework/web/server/ServerWebExchange.java b/spring-web/src/main/java/org/springframework/web/server/ServerWebExchange.java
@@ -146,14 +146,7 @@ default <T> T getAttributeOrDefault(String name, T defaultValue) {
 	 * @since 6.0.10
 	 * @see Part#delete()
 	 */
-	default Mono<Void> cleanupMultipart() {
-		return getMultipartData()
-				.onErrorResume(t -> Mono.empty())  // ignore errors reading multipart data
-				.flatMapIterable(Map::values)
-				.flatMapIterable(Function.identity())
-				.flatMap(part -> part.delete().onErrorResume(ex -> Mono.empty()))
-				.then();
-	}
+	Mono<Void> cleanupMultipart();
 
 	/**
 	 * Return the {@link LocaleContext} using the configured

diff --git a/...in/java/org/springframework/web/reactive/function/server/DefaultServerRequestBuilder.java b/...in/java/org/springframework/web/reactive/function/server/DefaultServerRequestBuilder.java
@@ -324,28 +324,30 @@ private static class DelegatingServerWebExchange implements ServerWebExchange {
 
 		private final Mono<MultiValueMap<String, Part>> multipartDataMono;
 
+		private volatile boolean multipartRead = false;
+
+
 		DelegatingServerWebExchange(ServerHttpRequest request, Map<String, Object> attributes,
 				ServerWebExchange delegate, List<HttpMessageReader<?>> messageReaders) {
 
 			this.request = request;
 			this.attributes = attributes;
 			this.delegate = delegate;
-			this.formDataMono = initFormData(request, messageReaders);
+			this.formDataMono = initFormData(messageReaders);
 			this.multipartDataMono = initMultipartData(request, messageReaders);
 		}
 
 		@SuppressWarnings("unchecked")
-		private static Mono<MultiValueMap<String, String>> initFormData(ServerHttpRequest request,
-				List<HttpMessageReader<?>> readers) {
-
+		private Mono<MultiValueMap<String, String>> initFormData(List<HttpMessageReader<?>> readers) {
 			try {
-				MediaType contentType = request.getHeaders().getContentType();
+				MediaType contentType = this.request.getHeaders().getContentType();
 				if (MediaType.APPLICATION_FORM_URLENCODED.isCompatibleWith(contentType)) {
 					return ((HttpMessageReader<MultiValueMap<String, String>>) readers.stream()
 							.filter(reader -> reader.canRead(FORM_DATA_TYPE, MediaType.APPLICATION_FORM_URLENCODED))
 							.findFirst()
 							.orElseThrow(() -> new IllegalStateException("No form data HttpMessageReader.")))
-							.readMono(FORM_DATA_TYPE, request, Hints.none())
+							.readMono(FORM_DATA_TYPE, this.request, Hints.none())
+							.doOnNext(ignored -> this.multipartRead = true)
 							.switchIfEmpty(EMPTY_FORM_DATA)
 							.cache();
 				}
@@ -398,7 +400,23 @@ public Mono<MultiValueMap<String, Part>> getMultipartData() {
 			return this.multipartDataMono;
 		}
 
-		// Delegating methods
+		@Override
+		public Mono<Void> cleanupMultipart() {
+			if (this.multipartRead) {
+				return getMultipartData()
+						.onErrorResume(t -> Mono.empty()) // ignore errors reading multipart data
+						.flatMapIterable(Map::values)
+						.flatMapIterable(Function.identity())
+						.flatMap(part -> part.delete()
+										.onErrorResume(ex -> Mono.empty()))
+						.then();
+			}
+			else {
+				return Mono.empty();
+			}
+		}
+
+        // Delegating methods
 
 		@Override
 		public ServerHttpResponse getResponse() {