[BAEL-6276] Exploring the New Filters on Spring Cloud Gateway (#16341)

* BAEL-6276: Fix the broken tests

* BAEL-6276: Add request header AddRequestHeadersIfNotPresent

* BAEL-6276: Add response header RemoveJsonAttributesResponseBody

* BAEL-6276: Example for CacheRequestBody

* BAEL-6276: Example for LocalResponseCache

* BAEL-6276: Add `redis-rate-limiter.requestedTokens` for `RequestRateLimiter`

spring-cloud-modules/spring-cloud-gateway/pom.xml

@@ -65,6 +65,14 @@
             <artifactId>jakarta.validation-api</artifactId>
             <version>${jakarta.validation-api.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-cache</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.github.ben-manes.caffeine</groupId>
+            <artifactId>caffeine</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-actuator</artifactId>
@@ -179,11 +187,12 @@
     </profiles>
 
     <properties>
+        <spring-boot.version>3.2.3</spring-boot.version>
         <spring-cloud-dependencies.version>2023.0.0</spring-cloud-dependencies.version>
         <hibernate-validator.version>8.0.1.Final</hibernate-validator.version>
         <redis.version>0.7.2</redis.version>
         <oauth2-oidc-sdk.version>9.19</oauth2-oidc-sdk.version>
-        <!-- <junit-bom.version>5.5.2</junit-bom.version> -->
+        <junit-jupiter.version>5.10.2</junit-jupiter.version>
         <jakarta.validation-api.version>3.0.2</jakarta.validation-api.version>
     </properties>
 

spring-cloud-modules/spring-cloud-gateway/src/main/java/com/baeldung/springcloudgateway/webfilters/CacheEvaluationFilter.java

@@ -0,0 +1,22 @@
+package com.baeldung.springcloudgateway.webfilters;
+
+import org.springframework.cloud.gateway.filter.GatewayFilterChain;
+import org.springframework.cloud.gateway.filter.GlobalFilter;
+import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
+import org.springframework.stereotype.Component;
+import org.springframework.web.server.ServerWebExchange;
+
+import reactor.core.publisher.Mono;
+
+@Component
+public class CacheEvaluationFilter implements GlobalFilter {
+
+    @Override
+    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
+        String body = exchange.getAttribute(ServerWebExchangeUtils.CACHED_REQUEST_BODY_ATTR);
+        if (body != null) {
+            exchange.getResponse().getHeaders().add("My-Header-Cache", body);
+        }
+        return chain.filter(exchange);
+    }
+}

spring-cloud-modules/spring-cloud-gateway/src/main/resources/application-webfilters.yml

@@ -9,6 +9,11 @@ spring:
     port: 6379
   cloud:
     gateway:
+      filter:
+        local-response-cache:
+          enabled: true
+          timeToLive: 20m
+          size: 6MB
       routes:
       - id: request_header_route
         uri: https://httpbin.org
@@ -17,6 +22,7 @@ spring:
         filters:
         - AddRequestHeader=My-Header-Good,Good
         - AddRequestHeader=My-Header-Remove,Remove
+        - AddRequestHeadersIfNotPresent=My-Header-Absent:Absent
         - AddRequestParameter=var, good
         - AddRequestParameter=var2, remove
         - MapRequestHeader=My-Header-Good, My-Header-Bad
@@ -31,15 +37,16 @@ spring:
         predicates:
         - Path=/header/post/**
         filters:
-        - AddResponseHeader=My-Header-Good,Good
-        - AddResponseHeader=My-Header-Set,Good
-        - AddResponseHeader=My-Header-Rewrite, password=12345678
         - DedupeResponseHeader=Access-Control-Allow-Credentials Access-Control-Allow-Origin
-        - AddResponseHeader=My-Header-Remove,Remove
         - SetResponseHeader=My-Header-Set, Set
         - RemoveResponseHeader=My-Header-Remove
         - RewriteResponseHeader=My-Header-Rewrite, password=[^&]+, password=***
         - RewriteLocationResponseHeader=AS_IN_REQUEST, Location, ,
+        - RemoveJsonAttributesResponseBody=form,Accept,true
+        - AddResponseHeader=My-Header-Good,Good
+        - AddResponseHeader=My-Header-Set,Good
+        - AddResponseHeader=My-Header-Remove,Remove
+        - AddResponseHeader=My-Header-Rewrite,password=12345678
         - StripPrefix=1
 
       - id: path_route
@@ -89,6 +96,17 @@ spring:
               factor: 2
               basedOnPreviousValue: false
 
+      - id: circuitbreaker_route
+        uri: https://httpbin.org
+        predicates:
+        - Path=/status/504
+        filters:
+        - name: CircuitBreaker
+          args:
+            name: myCircuitBreaker
+            fallbackUri: forward:/anything
+        - RewritePath=/status/504, /anything
+
       - id: request_rate_limiter
         uri: https://httpbin.org
         predicates:
@@ -99,4 +117,23 @@ spring:
           args:
             redis-rate-limiter.replenishRate: 10
             redis-rate-limiter.burstCapacity: 5
+            redis-rate-limiter.requestedTokens: 1
             key-resolver: "#{@userKeyResolver}"
+
+      - id: cache_request_body_route
+        uri: https://httpbin.org
+        predicates:
+        - Path=/cache/post/**
+        filters:
+        - StripPrefix=1
+        - name: CacheRequestBody
+          args:
+            bodyClass: java.lang.String
+
+      - id: cache_response_body_route
+        uri: https://httpbin.org
+        predicates:
+          - Path=/cache/get/**
+        filters:
+          - StripPrefix=1
+          - LocalResponseCache=10s,20MB

spring-cloud-modules/spring-cloud-gateway/src/test/java/com/baeldung/springcloudgateway/webfilters/WebFilterFactoriesLiveTest.java

@@ -1,11 +1,8 @@
 package com.baeldung.springcloudgateway.webfilters;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
-import org.assertj.core.api.Condition;
 import org.json.JSONException;
 import org.json.JSONObject;
 import org.junit.jupiter.api.BeforeEach;
@@ -23,9 +20,10 @@ import org.springframework.http.ResponseEntity;
 import org.springframework.test.context.ActiveProfiles;
 import org.springframework.test.web.reactive.server.WebTestClient;
 import org.springframework.test.web.reactive.server.WebTestClient.ResponseSpec;
+import org.springframework.web.reactive.function.BodyInserters;
 
 @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
-@ActiveProfiles("webfilters")
+@ActiveProfiles({"webfilters","nosecurity"})
 public class WebFilterFactoriesLiveTest {
 
     @LocalServerPort
@@ -55,6 +53,7 @@ public class WebFilterFactoriesLiveTest {
         assertThat(headers.getString("My-Header-Good")).isEqualTo("Good");
         assertThat(headers.getString("My-Header-Bad")).isEqualTo("Good");
         assertThat(headers.getString("My-Header-Set")).isEqualTo("Set");
+        assertThat(headers.getString("My-Header-Absent")).isEqualTo("Absent");
         assertTrue(headers.isNull("My-Header-Remove"));
         JSONObject vars = json.getJSONObject("args");
         assertThat(vars.getString("var")).isEqualTo("good");
@@ -75,7 +74,10 @@ public class WebFilterFactoriesLiveTest {
           .expectHeader()
           .valueEquals("My-Header-Good", "Good")
           .expectHeader()
-          .doesNotExist("My-Header-Remove");
+          .doesNotExist("My-Header-Remove")
+          .expectBody()
+          .jsonPath("$.headers.Accept").doesNotExist()
+          .jsonPath("form").doesNotExist();
     }
 
     @Test
@@ -133,4 +135,28 @@ public class WebFilterFactoriesLiveTest {
         JSONObject json = new JSONObject(response.getBody());
         assertThat(json.getString("url")).contains("anything");
     }
+
+    @Test
+    public void whenCallCachePostThroughGateway_thenMyHeaderCacheIsSet() {
+        ResponseSpec response = client.post()
+            .uri("/cache/post")
+            .body(BodyInserters.fromValue("CachedBody"))
+            .exchange();
+
+        response.expectStatus()
+            .isOk()
+            .expectHeader()
+            .valueEquals("My-Header-Cache", "CachedBody");
+    }
+
+    @Test
+    public void whenCallCacheGetThroughGateway_thenCacheControlIsSet() {
+        ResponseSpec response = client.get()
+            .uri("/cache/get")
+            .exchange();
+
+        response.expectStatus().isOk()
+            .expectHeader()
+            .valueEquals("Cache-Control", "max-age=10");
+    }
 }