Change default appcache manifest file extension

This commit changes the default file extension configured with
`AppCacheManifestTranformer`. This ResourceTransformer was previously
considering `.manifest` files by default, but this has been changed in
the official spec to `appcache`, in order not to clash with Microsoft's
unregistered application/manifest type.

Issue: SPR-14687

spring-web-reactive/src/main/java/org/springframework/web/reactive/resource/AppCacheManifestTransformer.java

@@ -48,7 +48,7 @@ import org.springframework.web.server.ServerWebExchange;
  * of the manifest in order to trigger an appcache reload in the browser.
  * </ul>
  *
- * All files that have the ".manifest" file extension, or the extension given
+ * All files that have the ".appcache" file extension, or the extension given
  * in the constructor, will be transformed by this class.
  *
  * <p>This hash is computed using the content of the appcache manifest and the
@@ -58,7 +58,7 @@ import org.springframework.web.server.ServerWebExchange;
  * @author Rossen Stoyanchev
  * @author Brian Clozel
  * @since 5.0
- * @see <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/offline.html#offline">HTML5 offline applications spec</a>
+ * @see <a href="https://html.spec.whatwg.org/multipage/browsers.html#offline">HTML5 offline applications spec</a>
  */
 public class AppCacheManifestTransformer extends ResourceTransformerSupport {
 
@@ -75,10 +75,10 @@ public class AppCacheManifestTransformer extends ResourceTransformerSupport {
 
 
 	/**
-	 * Create an AppCacheResourceTransformer that transforms files with extension ".manifest".
+	 * Create an AppCacheResourceTransformer that transforms files with extension ".appcache".
 	 */
 	public AppCacheManifestTransformer() {
-		this("manifest");
+		this("appcache");
 	}
 
 	/**

spring-web-reactive/src/test/java/org/springframework/web/reactive/resource/AppCacheManifestTransformerTests.java

@@ -82,7 +82,7 @@ public class AppCacheManifestTransformerTests {
 
 	@Test
 	public void syntaxErrorInManifest() throws Exception {
-		Resource resource = new ClassPathResource("test/error.manifest", getClass());
+		Resource resource = new ClassPathResource("test/error.appcache", getClass());
 		given(this.chain.transform(this.exchange, resource)).willReturn(resource);
 
 		Resource result = this.transformer.transform(this.exchange, resource, this.chain);
@@ -105,7 +105,7 @@ public class AppCacheManifestTransformerTests {
 		transformers.add(new CssLinkResourceTransformer());
 		this.chain = new DefaultResourceTransformerChain(resolverChain, transformers);
 
-		Resource resource = new ClassPathResource("test/appcache.manifest", getClass());
+		Resource resource = new ClassPathResource("test/test.appcache", getClass());
 		Resource result = this.transformer.transform(this.exchange, resource, this.chain);
 		byte[] bytes = FileCopyUtils.copyToByteArray(result.getInputStream());
 		String content = new String(bytes, "UTF-8");

spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AppCacheManifestTransformer.java

@@ -47,7 +47,7 @@ import org.springframework.util.StringUtils;
  * thus changing the content of the manifest in order to trigger an appcache reload in the browser.
  * </ul>
  *
- * All files that have the ".manifest" file extension, or the extension given in the constructor,
+ * All files that have the ".appcache" file extension, or the extension given in the constructor,
  * will be transformed by this class.
  *
  * <p>This hash is computed using the content of the appcache manifest and the content of the linked resources;
@@ -55,7 +55,7 @@ import org.springframework.util.StringUtils;
  *
  * @author Brian Clozel
  * @since 4.1
- * @see <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/offline.html#offline">HTML5 offline applications spec</a>
+ * @see <a href="https://html.spec.whatwg.org/multipage/browsers.html#offline">HTML5 offline applications spec</a>
  */
 public class AppCacheManifestTransformer extends ResourceTransformerSupport {
 
@@ -72,10 +72,10 @@ public class AppCacheManifestTransformer extends ResourceTransformerSupport {
 
 
 	/**
-	 * Create an AppCacheResourceTransformer that transforms files with extension ".manifest".
+	 * Create an AppCacheResourceTransformer that transforms files with extension ".appcache".
 	 */
 	public AppCacheManifestTransformer() {
-		this("manifest");
+		this("appcache");
 	}
 
 	/**

spring-webmvc/src/test/java/org/springframework/web/servlet/resource/AppCacheManifestTransformerTests.java

@@ -66,7 +66,7 @@ public class AppCacheManifestTransformerTests {
 
 	@Test
 	public void syntaxErrorInManifest() throws Exception {
-		Resource resource = new ClassPathResource("test/error.manifest", getClass());
+		Resource resource = new ClassPathResource("test/error.appcache", getClass());
 		given(this.chain.transform(this.request, resource)).willReturn(resource);
 
 		Resource result = this.transformer.transform(this.request, resource, this.chain);
@@ -89,7 +89,7 @@ public class AppCacheManifestTransformerTests {
 		transformers.add(new CssLinkResourceTransformer());
 		this.chain = new DefaultResourceTransformerChain(resolverChain, transformers);
 
-		Resource resource = new ClassPathResource("test/appcache.manifest", getClass());
+		Resource resource = new ClassPathResource("test/test.appcache", getClass());
 		Resource result = this.transformer.transform(this.request, resource, this.chain);
 		byte[] bytes = FileCopyUtils.copyToByteArray(result.getInputStream());
 		String content = new String(bytes, "UTF-8");