From 40bf550d565d39d9604194fc0d14be4a85103c71 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20Basl=C3=A9?= <simon.basle@broadcom.com>
Date: Mon, 15 Apr 2024 14:20:48 +0200
Subject: [PATCH] Ensure multipart data is deleted in WebFlux when connection
 terminates

Before this change temporary files would not consistently be deleted
when the connection which uploads the multipart files closes naturally.

This change uses the usingWhen Reactor operator to ensure that the
termination of the connection doesn't prevent individual file parts
from being deleted due to a cancellation signal.

See gh-31217
Closes gh-32638
---
 .../adapter/DefaultServerWebExchange.java       | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/spring-web/src/main/java/org/springframework/web/server/adapter/DefaultServerWebExchange.java b/spring-web/src/main/java/org/springframework/web/server/adapter/DefaultServerWebExchange.java
index 21a3193158..2c6f73bfbf 100644
--- a/spring-web/src/main/java/org/springframework/web/server/adapter/DefaultServerWebExchange.java
+++ b/spring-web/src/main/java/org/springframework/web/server/adapter/DefaultServerWebExchange.java
@@ -24,7 +24,9 @@ import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Function;
+import java.util.stream.Collectors;
 
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 import org.springframework.context.ApplicationContext;
@@ -249,13 +251,10 @@ public class DefaultServerWebExchange implements ServerWebExchange {
 	public Mono<Void> cleanupMultipart() {
 		return Mono.defer(() -> {
 			if (this.multipartRead) {
-				return getMultipartData()
-						.onErrorComplete()
-						.flatMapIterable(Map::values)
-						.flatMapIterable(Function.identity())
-						.flatMap(part -> part.delete()
-									.onErrorComplete())
-						.then();
+				return Mono.usingWhen(getMultipartData().onErrorComplete().map(this::collectParts),
+						parts -> Mono.empty(),
+						parts -> Flux.fromIterable(parts).flatMap(part -> part.delete().onErrorComplete())
+				);
 			}
 			else {
 				return Mono.empty();
@@ -263,6 +262,10 @@ public class DefaultServerWebExchange implements ServerWebExchange {
 		});
 	}
 
+	private List<Part> collectParts(MultiValueMap<String, Part> multipartData) {
+		return multipartData.values().stream().flatMap(List::stream).collect(Collectors.toList());
+	}
+
 	@Override
 	public LocaleContext getLocaleContext() {
 		return this.localeContextResolver.resolveLocaleContext(this);