Add zstd content coding support to EncodedResourceResolver

framework-docs/modules/ROOT/pages/web/webflux/config.adoc

@@ -620,7 +620,7 @@ resource URLs, since there are no view technologies that can make use of a non-b
 of resolvers and transformers. When serving only local resources, the workaround is to use
 `ResourceUrlProvider` directly (for example, through a custom element) and block.
 
-Note that, when using both `EncodedResourceResolver` (for example, Gzip, Brotli encoded) and
+Note that, when using both `EncodedResourceResolver` (for example, Gzip, Brotli, Zstd encoded) and
 `VersionedResourceResolver`, they must be registered in that order, to ensure content-based
 versions are always computed reliably based on the unencoded file.
 

framework-docs/modules/ROOT/pages/web/webmvc/mvc-config/static-resources.adoc

@@ -40,8 +40,8 @@ bean so that it can be injected into others. You can also make the rewrite trans
 `ResourceUrlEncodingFilter` for Thymeleaf, JSPs, FreeMarker, and others with URL tags that
 rely on `HttpServletResponse#encodeURL`.
 
-Note that, when using both `EncodedResourceResolver` (for example, for serving gzipped or
-brotli-encoded resources) and `VersionResourceResolver`, you must register them in this order.
+Note that, when using both `EncodedResourceResolver` (for example, for serving gzipped, brotli,
+or zstd encoded resources) and `VersionResourceResolver`, you must register them in this order.
 That ensures content-based versions are always computed reliably, based on the unencoded file.
 
 For https://www.webjars.org/documentation[WebJars], versioned URLs like

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

@@ -83,7 +83,7 @@ public Cache getCache() {
 	 * {@literal "Accept-Encoding"} header for which to cache resource variations.
 	 * <p>The codings configured here are generally expected to match those
 	 * configured on {@link EncodedResourceResolver#setContentCodings(List)}.
-	 * <p>By default this property is set to {@literal ["br", "gzip"]} based on
+	 * <p>By default this property is set to {@literal ["zstd", "br", "gzip"]} based on
 	 * the value of {@link EncodedResourceResolver#DEFAULT_CODINGS}.
 	 * @param codings one or more supported content codings
 	 * @since 5.1

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

@@ -44,8 +44,8 @@
 
 /**
  * Resolver that delegates to the chain, and if a resource is found, it then
- * attempts to find an encoded (for example, gzip, brotli) variant that is acceptable
- * based on the "Accept-Encoding" request header.
+ * attempts to find an encoded (for example, gzip, brotli, zstd) variant that is
+ * acceptable based on the "Accept-Encoding" request header.
  *
  * <p>The list of supported {@link #setContentCodings(List) contentCodings} can
  * be configured, in order of preference, and each coding must be associated
@@ -56,14 +56,15 @@
  * ensure the version calculation is not impacted by the encoding.
  *
  * @author Rossen Stoyanchev
+ * @author Toshiaki Maki
  * @since 5.1
  */
 public class EncodedResourceResolver extends AbstractResourceResolver {
 
 	/**
 	 * The default content codings.
 	 */
-	public static final List<String> DEFAULT_CODINGS = Arrays.asList("br", "gzip");
+	public static final List<String> DEFAULT_CODINGS = Arrays.asList("zstd", "br", "gzip");
 
 
 	private final List<String> contentCodings = new ArrayList<>(DEFAULT_CODINGS);
@@ -74,6 +75,7 @@ public class EncodedResourceResolver extends AbstractResourceResolver {
 	public EncodedResourceResolver() {
 		this.extensions.put("gzip", ".gz");
 		this.extensions.put("br", ".br");
+		this.extensions.put("zstd", ".zst");
 	}
 
 
@@ -87,7 +89,7 @@ public EncodedResourceResolver() {
 	 * customizations to the list of codings here should be matched by
 	 * customizations to the same list in {@link CachingResourceResolver} to
 	 * ensure encoded variants of a resource are cached under separate keys.
-	 * <p>By default this property is set to {@literal ["br", "gzip"]}.
+	 * <p>By default this property is set to {@literal ["zstd", "br", "gzip"]}.
 	 * @param codings one or more supported content codings
 	 */
 	public void setContentCodings(List<String> codings) {
@@ -106,8 +108,8 @@ public List<String> getContentCodings() {
 	/**
 	 * Configure mappings from content codings to file extensions. A dot "."
 	 * will be prepended in front of the extension value if not present.
-	 * <p>By default this is configured with {@literal ["br" -> ".br"]} and
-	 * {@literal ["gzip" -> ".gz"]}.
+	 * <p>By default this is configured with {@literal ["zstd" -> ".zst"]},
+	 * {@literal ["br" -> ".br"]} and {@literal ["gzip" -> ".gz"]}.
 	 * @param extensions the extensions to use.
 	 * @see #registerExtension(String, String)
 	 */

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

@@ -40,6 +40,7 @@
  * Tests for {@link EncodedResourceResolver}.
  *
  * @author Rossen Stoyanchev
+ * @author Toshiaki Maki
  */
 @ExtendWith(GzipSupport.class)
 class EncodedResourceResolverTests {
@@ -91,6 +92,24 @@ void resolveGzipped(GzippedFiles gzippedFiles) {
 		assertThat(headers.getFirst(HttpHeaders.VARY)).isEqualTo("Accept-Encoding");
 	}
 
+	@Test
+	void resolveZstd() {
+
+		MockServerWebExchange exchange = MockServerWebExchange.from(
+				MockServerHttpRequest.get("").header("Accept-Encoding", "zstd"));
+
+		String file = "js/foo.js";
+		Resource actual = this.resolver.resolveResource(exchange, file, this.locations).block(TIMEOUT);
+
+		assertThat(actual.getDescription()).isEqualTo(getResource(file + ".zst").getDescription());
+		assertThat(actual.getFilename()).isEqualTo(getResource(file).getFilename());
+
+		assertThat(actual).isInstanceOf(HttpResource.class);
+		HttpHeaders headers = ((HttpResource) actual).getResponseHeaders();
+		assertThat(headers.getFirst(HttpHeaders.CONTENT_ENCODING)).isEqualTo("zstd");
+		assertThat(headers.getFirst(HttpHeaders.VARY)).isEqualTo("Accept-Encoding");
+	}
+
 	@Test
 	void resolveGzippedWithVersion(GzippedFiles gzippedFiles) {
 

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

@@ -83,7 +83,7 @@ public Cache getCache() {
 	 * {@literal "Accept-Encoding"} header for which to cache resource variations.
 	 * <p>The codings configured here are generally expected to match those
 	 * configured on {@link EncodedResourceResolver#setContentCodings(List)}.
-	 * <p>By default this property is set to {@literal ["br", "gzip"]} based on
+	 * <p>By default this property is set to {@literal ["zstd", "br", "gzip"]} based on
 	 * the value of {@link EncodedResourceResolver#DEFAULT_CODINGS}.
 	 * @param codings one or more supported content codings
 	 * @since 5.1

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

@@ -43,8 +43,8 @@
 
 /**
  * Resolver that delegates to the chain, and if a resource is found, it then
- * attempts to find an encoded (for example, gzip, brotli) variant that is acceptable
- * based on the "Accept-Encoding" request header.
+ * attempts to find an encoded (for example, gzip, brotli, zstd) variant that is
+ * acceptable based on the "Accept-Encoding" request header.
  *
  * <p>The list of supported {@link #setContentCodings(List) contentCodings} can
  * be configured, in order of preference, and each coding must be associated
@@ -55,14 +55,15 @@
  * ensure the version calculation is not impacted by the encoding.
  *
  * @author Rossen Stoyanchev
+ * @author Toshiaki Maki
  * @since 5.1
  */
 public class EncodedResourceResolver extends AbstractResourceResolver {
 
 	/**
 	 * The default content codings.
 	 */
-	public static final List<String> DEFAULT_CODINGS = Arrays.asList("br", "gzip");
+	public static final List<String> DEFAULT_CODINGS = Arrays.asList("zstd", "br", "gzip");
 
 
 	private final List<String> contentCodings = new ArrayList<>(DEFAULT_CODINGS);
@@ -73,6 +74,7 @@ public class EncodedResourceResolver extends AbstractResourceResolver {
 	public EncodedResourceResolver() {
 		this.extensions.put("gzip", ".gz");
 		this.extensions.put("br", ".br");
+		this.extensions.put("zstd", ".zst");
 	}
 
 
@@ -86,7 +88,7 @@ public EncodedResourceResolver() {
 	 * customizations to the list of codings here should be matched by
 	 * customizations to the same list in {@link CachingResourceResolver} to
 	 * ensure encoded variants of a resource are cached under separate keys.
-	 * <p>By default this property is set to {@literal ["br", "gzip"]}.
+	 * <p>By default this property is set to {@literal ["zstd", "br", "gzip"]}.
 	 * @param codings one or more supported content codings
 	 */
 	public void setContentCodings(List<String> codings) {
@@ -105,8 +107,8 @@ public List<String> getContentCodings() {
 	/**
 	 * Configure mappings from content codings to file extensions. A dot "."
 	 * will be prepended in front of the extension value if not present.
-	 * <p>By default this is configured with {@literal ["br" -> ".br"]} and
-	 * {@literal ["gzip" -> ".gz"]}.
+	 * <p>By default this is configured with {@literal ["zstd" -> ".zst"]},
+	 * {@literal ["br" -> ".br"]} and {@literal ["gzip" -> ".gz"]}.
 	 * @param extensions the extensions to use.
 	 * @see #registerExtension(String, String)
 	 */

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

@@ -39,6 +39,7 @@
  *
  * @author Jeremy Grelle
  * @author Rossen Stoyanchev
+ * @author Toshiaki Maki
  */
 @ExtendWith(GzipSupport.class)
 class EncodedResourceResolverTests {
@@ -84,6 +85,22 @@ void resolveGzipped(GzippedFiles gzippedFiles) {
 		assertThat(headers.getFirst(HttpHeaders.VARY)).isEqualTo("Accept-Encoding");
 	}
 
+	@Test
+	void resolveZstd() {
+		String file = "js/foo.js";
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.addHeader("Accept-Encoding", "zstd");
+		Resource actual = this.resolver.resolveResource(request, file, this.locations);
+
+		assertThat(actual.getDescription()).isEqualTo(getResource(file + ".zst").getDescription());
+		assertThat(actual.getFilename()).isEqualTo(getResource(file).getFilename());
+
+		assertThat(actual).isInstanceOf(HttpResource.class);
+		HttpHeaders headers = ((HttpResource) actual).getResponseHeaders();
+		assertThat(headers.getFirst(HttpHeaders.CONTENT_ENCODING)).isEqualTo("zstd");
+		assertThat(headers.getFirst(HttpHeaders.VARY)).isEqualTo("Accept-Encoding");
+	}
+
 	@Test
 	void resolveGzippedWithVersion(GzippedFiles gzippedFiles) {
 		gzippedFiles.create("foo.css");