Add LocalResponseCache filter to Spring Cloud Gateway Server Web MVC

docs/modules/ROOT/nav.adoc

@@ -82,7 +82,7 @@
 *** xref:spring-cloud-gateway-server-webmvc/filters/deduperesponseheader.adoc[]
 *** xref:spring-cloud-gateway-server-webmvc/filters/fallback-headers.adoc[]
 *** xref:spring-cloud-gateway-server-webmvc/filters/loadbalancer.adoc[]
-//*** xref:spring-cloud-gateway-server-mvc/filters/local-cache-response-filter.adoc[]
+*** xref:spring-cloud-gateway-server-webmvc/filters/local-cache-response-filter.adoc[]
 *** xref:spring-cloud-gateway-server-webmvc/filters/maprequestheader.adoc[]
 *** xref:spring-cloud-gateway-server-webmvc/filters/modifyrequestbody.adoc[]
 *** xref:spring-cloud-gateway-server-webmvc/filters/modifyresponsebody.adoc[]

docs/modules/ROOT/pages/spring-cloud-gateway-server-webmvc/filters/local-cache-response-filter.adoc

@@ -6,50 +6,58 @@ This filter allows caching the response body and headers to follow these rules:
 * It can only cache bodiless GET requests.
 * It caches the response only for one of the following status codes: HTTP 200 (OK), HTTP 206 (Partial Content), or HTTP 301 (Moved Permanently).
 * Response data is not cached if `Cache-Control` header does not allow it (`no-store` present in the request or `no-store` or `private` present in the response).
-* If the response is already cached and a new request is performed with no-cache value in `Cache-Control` header, it returns a bodiless response with 304 (Not Modified).
+* Response data is not cached if the response `Vary` header is `*`.
+* Response data is not cached if the response has a streaming media type (see `spring.cloud.gateway.server.webmvc.streaming-media-types`).
+* If a new request is performed with `no-cache` value in `Cache-Control` header, the request is forwarded to the upstream and the existing cache entry is kept.
 
-This filter configures the local response cache per route and is available only if the `spring.cloud.gateway.filter.local-response-cache.enabled` property is enabled. And a xref:spring-cloud-gateway-server-webflux/global-filters.adoc#local-cache-response-global-filter[local response cache configured globally] is also available as feature.
+This filter configures the local response cache per route.
 
 It accepts the first parameter to override the time to expire a cache entry (expressed in `s` for seconds, `m` for minutes, and `h` for hours) and a second parameter to set the maximum size of the cache to evict entries for this route (`KB`, `MB`, or `GB`).
+Both parameters are optional: if the time to live is not set, it defaults to 5 minutes; if the maximum size is not set, the cache is not size-bounded.
 
-The following listing shows how to add local response cache  filter:
+The following listing shows how to add the local response cache filter:
 
-[source,java]
-----
-@Bean
-public RouteLocator routes(RouteLocatorBuilder builder) {
-    return builder.routes()
-        .route("rewrite_response_upper", r -> r.host("*.rewriteresponseupper.org")
-            .filters(f -> f.prefixPath("/httpbin")
-        		.localResponseCache(Duration.ofMinutes(30), "500MB")
-            ).uri(uri))
-        .build();
-}
-----
-
-or this
-
-.application.yaml
+.application.yml
 [source,yaml]
 ----
 spring:
   cloud:
     gateway:
-      routes:
-      - id: resource
-        uri: http://localhost:9000
-        predicates:
-        - Path=/resource
-        filters:
-        - LocalResponseCache=30m,500MB
+      server:
+        webmvc:
+          routes:
+            - id: resource
+              uri: http://localhost:9000
+              predicates:
+              - Path=/resource
+              filters:
+              - LocalResponseCache=30m,500MB
+----
+
+.GatewaySampleApplication.java
+[source,java]
+----
+import static org.springframework.cloud.gateway.server.mvc.filter.BeforeFilterFunctions.uri;
+import static org.springframework.cloud.gateway.server.mvc.filter.ResponseCacheFilterFunctions.localResponseCache;
+import static org.springframework.cloud.gateway.server.mvc.handler.GatewayRouterFunctions.route;
+import static org.springframework.cloud.gateway.server.mvc.handler.HandlerFunctions.http;
+
+@Configuration
+class RouteConfiguration {
+
+    @Bean
+    public RouterFunction<ServerResponse> gatewayRouterFunctionsCache() {
+        return route("resource")
+            .GET("/resource", http())
+            .before(uri("http://localhost:9000"))
+            .filter(localResponseCache(Duration.ofMinutes(30), DataSize.parse("500MB")))
+            .build();
+    }
+}
 ----
 
 NOTE: This filter also automatically calculates the `max-age` value in the HTTP `Cache-Control` header.
-Only if `max-age` is present on the original response is the value rewritten with the number of seconds set in the `timeToLive` configuration parameter.
+If `max-age` is not present on the original response, the value is set to the number of seconds set in the `timeToLive` configuration parameter.
 In consecutive calls, this value is recalculated with the number of seconds left until the response expires.
 
-NOTE: To enable this feature, add `com.github.ben-manes.caffeine:caffeine` and `spring-boot-starter-cache` as project dependencies.
-
-WARNING: If your project creates custom `CacheManager` beans, it will either need to be marked with `@Primary` or injected using `@Qualifier`.
-
-
+NOTE: To enable this feature, add `com.github.ben-manes.caffeine:caffeine` as a project dependency.

spring-cloud-gateway-server-webmvc/pom.xml

@@ -92,6 +92,11 @@
             <optional>true</optional>
         </dependency>
         <!-- Third party dependencies -->
+        <dependency>
+            <groupId>com.github.ben-manes.caffeine</groupId>
+            <artifactId>caffeine</artifactId>
+            <optional>true</optional>
+        </dependency>
         <dependency>
             <groupId>com.bucket4j</groupId>
             <artifactId>bucket4j_jdk17-core</artifactId>
@@ -163,11 +168,6 @@
             <artifactId>bucket4j_jdk17-caffeine</artifactId>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>com.github.ben-manes.caffeine</groupId>
-            <artifactId>caffeine</artifactId>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>org.testcontainers</groupId>
             <artifactId>testcontainers-junit-jupiter</artifactId>

spring-cloud-gateway-server-webmvc/src/main/java/org/springframework/cloud/gateway/server/mvc/filter/FilterAutoConfiguration.java

@@ -20,6 +20,8 @@
 import java.util.Objects;
 import java.util.function.Function;
 
+import com.github.benmanes.caffeine.cache.Caffeine;
+import com.github.benmanes.caffeine.cache.Weigher;
 import io.github.bucket4j.BucketConfiguration;
 
 import org.springframework.beans.factory.BeanFactory;
@@ -113,4 +115,15 @@ public TokenRelayFilterFunctions.FilterSupplier tokenRelayFilterFunctionsSupplie
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnClass({ Weigher.class, Caffeine.class })
+	static class ResponseCacheFilterConfiguration {
+
+		@Bean
+		public ResponseCacheFilterFunctions.FilterSupplier responseCacheFilterFunctionsSupplier() {
+			return new ResponseCacheFilterFunctions.FilterSupplier();
+		}
+
+	}
+
 }