Update more places to use quoteETagIfNecessary

Closes gh-33412

spring-web/src/main/java/org/springframework/http/HttpHeaders.java

@@ -1063,11 +1063,11 @@ public class HttpHeaders implements MultiValueMap<String, String>, Serializable
 	/**
 	 * Set the (new) entity tag of the body, as specified by the {@code ETag} header.
 	 */
-	public void setETag(@Nullable String etag) {
-		if (etag != null) {
-			Assert.isTrue(etag.startsWith("\"") || etag.startsWith("W/\""), "ETag does not start with W/\" or \"");
-			Assert.isTrue(etag.endsWith("\""), "ETag does not end with \"");
-			set(ETAG, etag);
+	public void setETag(@Nullable String eTag) {
+		if (eTag != null) {
+			Assert.isTrue(eTag.startsWith("\"") || eTag.startsWith("W/\""), "ETag does not start with W/\" or \"");
+			Assert.isTrue(eTag.endsWith("\""), "ETag does not end with \"");
+			set(ETAG, eTag);
 		}
 		else {
 			remove(ETAG);

spring-web/src/main/java/org/springframework/web/context/request/ServletWebRequest.java

@@ -247,23 +247,25 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 		return true;
 	}
 
-	private boolean matchRequestedETags(Enumeration<String> requestedETags, @Nullable String etag, boolean weakCompare) {
-		etag = padEtagIfNecessary(etag);
+	private boolean matchRequestedETags(Enumeration<String> requestedETags, @Nullable String eTag, boolean weakCompare) {
+		if (StringUtils.hasLength(eTag)) {
+			eTag = ETag.quoteETagIfNecessary(eTag);
+		}
 		while (requestedETags.hasMoreElements()) {
 			// Compare weak/strong ETags as per https://datatracker.ietf.org/doc/html/rfc9110#section-8.8.3
 			for (ETag requestedETag : ETag.parse(requestedETags.nextElement())) {
 				// only consider "lost updates" checks for unsafe HTTP methods
-				if (requestedETag.isWildcard() && StringUtils.hasLength(etag)
+				if (requestedETag.isWildcard() && StringUtils.hasLength(eTag)
 						&& !SAFE_METHODS.contains(getRequest().getMethod())) {
 					return false;
 				}
 				if (weakCompare) {
-					if (etagWeakMatch(etag, requestedETag.formattedTag())) {
+					if (etagWeakMatch(eTag, requestedETag.formattedTag())) {
 						return false;
 					}
 				}
 				else {
-					if (etagStrongMatch(etag, requestedETag.formattedTag())) {
+					if (etagStrongMatch(eTag, requestedETag.formattedTag())) {
 						return false;
 					}
 				}
@@ -272,17 +274,6 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 		return true;
 	}
 
-	@Nullable
-	private String padEtagIfNecessary(@Nullable String etag) {
-		if (!StringUtils.hasLength(etag)) {
-			return etag;
-		}
-		if ((etag.startsWith("\"") || etag.startsWith("W/\"")) && etag.endsWith("\"")) {
-			return etag;
-		}
-		return "\"" + etag + "\"";
-	}
-
 	private boolean etagStrongMatch(@Nullable String first, @Nullable String second) {
 		if (!StringUtils.hasLength(first) || first.startsWith("W/")) {
 			return false;
@@ -346,13 +337,13 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 		}
 	}
 
-	private void addCachingResponseHeaders(@Nullable String etag, long lastModifiedTimestamp) {
+	private void addCachingResponseHeaders(@Nullable String eTag, long lastModifiedTimestamp) {
 		if (getResponse() != null && SAFE_METHODS.contains(getRequest().getMethod())) {
 			if (lastModifiedTimestamp > 0 && parseDateValue(getResponse().getHeader(HttpHeaders.LAST_MODIFIED)) == -1) {
 				getResponse().setDateHeader(HttpHeaders.LAST_MODIFIED, lastModifiedTimestamp);
 			}
-			if (StringUtils.hasLength(etag) && getResponse().getHeader(HttpHeaders.ETAG) == null) {
-				getResponse().setHeader(HttpHeaders.ETAG, padEtagIfNecessary(etag));
+			if (StringUtils.hasLength(eTag) && getResponse().getHeader(HttpHeaders.ETAG) == null) {
+				getResponse().setHeader(HttpHeaders.ETAG, ETag.quoteETagIfNecessary(eTag));
 			}
 		}
 	}

spring-web/src/main/java/org/springframework/web/server/adapter/DefaultServerWebExchange.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.
@@ -33,6 +33,7 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.i18n.LocaleContext;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.codec.Hints;
+import org.springframework.http.ETag;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
@@ -341,7 +342,9 @@ public class DefaultServerWebExchange implements ServerWebExchange {
 	}
 
 	private boolean matchRequestedETags(List<String> requestedETags, @Nullable String eTag, boolean weakCompare) {
-		eTag = padEtagIfNecessary(eTag);
+		if (StringUtils.hasLength(eTag)) {
+			eTag = ETag.quoteETagIfNecessary(eTag);
+		}
 		for (String clientEtag : requestedETags) {
 			// only consider "lost updates" checks for unsafe HTTP methods
 			if ("*".equals(clientEtag) && StringUtils.hasLength(eTag)
@@ -363,17 +366,6 @@ public class DefaultServerWebExchange implements ServerWebExchange {
 		return true;
 	}
 
-	@Nullable
-	private String padEtagIfNecessary(@Nullable String etag) {
-		if (!StringUtils.hasLength(etag)) {
-			return etag;
-		}
-		if ((etag.startsWith("\"") || etag.startsWith("W/\"")) && etag.endsWith("\"")) {
-			return etag;
-		}
-		return "\"" + etag + "\"";
-	}
-
 	private boolean eTagStrongMatch(@Nullable String first, @Nullable String second) {
 		if (!StringUtils.hasLength(first) || first.startsWith("W/")) {
 			return false;
@@ -431,7 +423,7 @@ public class DefaultServerWebExchange implements ServerWebExchange {
 				getResponseHeaders().setLastModified(lastModified.toEpochMilli());
 			}
 			if (StringUtils.hasLength(eTag) && getResponseHeaders().getETag() == null) {
-				getResponseHeaders().setETag(padEtagIfNecessary(eTag));
+				getResponseHeaders().setETag(ETag.quoteETagIfNecessary(eTag));
 			}
 		}
 	}