spring cloud : spring cloud gateway - custom filter, global filter

springcloud/apigateway-service/src/main/java/com/example/apigatewayservice/filter/CustomFilter.java

@@ -0,0 +1,38 @@
+package com.example.apigatewayservice.filter;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.cloud.gateway.filter.GatewayFilter;
+import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.stereotype.Component;
+import reactor.core.publisher.Mono;
+
+@Component
+@Slf4j
+public class CustomFilter extends AbstractGatewayFilterFactory<CustomFilter.Config> {
+
+    public CustomFilter() {
+        super(Config.class);
+    }
+
+    @Override
+    public GatewayFilter apply(Config config) {
+        // Custom Pre Filter
+        return (exchange, chain) -> {
+            ServerHttpRequest request = exchange.getRequest();
+            ServerHttpResponse response = exchange.getResponse();
+
+            log.info("Custom PRE filter: request id -> {}", request.getId());
+
+            // Custom Post Filter
+            return chain.filter(exchange).then(Mono.fromRunnable(() -> {
+                log.info("Custom POST filter: request code -> {}", response.getStatusCode());
+            }));
+        };
+    }
+
+    public static class Config {
+        // Put the configuration properties
+    }
+}

springcloud/apigateway-service/src/main/java/com/example/apigatewayservice/filter/GlobalFilter.java

@@ -0,0 +1,47 @@
+package com.example.apigatewayservice.filter;
+
+import lombok.Data;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.cloud.gateway.filter.GatewayFilter;
+import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.stereotype.Component;
+import reactor.core.publisher.Mono;
+
+@Component
+@Slf4j
+public class GlobalFilter extends AbstractGatewayFilterFactory<GlobalFilter.Config> {
+
+    public GlobalFilter() {
+        super(Config.class);
+    }
+
+    @Override
+    public GatewayFilter apply(Config config) {
+
+        return (exchange, chain) -> {
+            ServerHttpRequest request = exchange.getRequest();
+            ServerHttpResponse response = exchange.getResponse();
+
+            log.info("Global filter baseMessage : {}", config.getBaseMessage());
+
+            if (config.isPreLogger()) {
+                log.info("Global filter Start: request id -> {}", request.getId());
+            }
+
+            return chain.filter(exchange).then(Mono.fromRunnable(() -> {
+                if (config.isPostLogger()) {
+                    log.info("Global filter End: response code -> {}", response.getStatusCode());
+                }
+            }));
+        };
+    }
+
+    @Data
+    public static class Config {
+        private String baseMessage;
+        private boolean preLogger;
+        private boolean postLogger;
+    }
+}

springcloud/apigateway-service/src/main/resources/application.yml

@@ -14,18 +14,26 @@ spring:
 
   cloud:
     gateway:
+      default-filters:
+        - name: GlobalFilter
+          args:
+            baseMessage: Spring Cloud Gateway Global Filter
+            preLogger: true
+            postLogger: true
       routes:
         - id: first-service
           uri: http://localhost:8081/
           predicates:
             - Path=/first-service/**
           filters:
-            - AddRequestHeader=first-request, first-request-header2
-            - AddResponseHeader=first-response, first-response-header2
+#            - AddRequestHeader=first-request, first-request-header2
+#            - AddResponseHeader=first-response, first-response-header2
+            - CustomFilter
         - id: second-service
           uri: http://localhost:8082/
           predicates:
             - Path=/second-service/**
           filters:
-            - AddRequestHeader=second-request, second-request-header2
-            - AddResponseHeader=second-response, second-response-header2
+#            - AddRequestHeader=second-request, second-request-header2
+#            - AddResponseHeader=second-response, second-response-header2
+            - CustomFilter

springcloud/first-service/src/main/java/com/example/firstservice/FirstServiceController.java

@@ -21,4 +21,9 @@ public class FirstServiceController {
         log.info(header);
         return "Hello World in First Service.";
     }
+
+    @GetMapping("/check")
+    public String check() {
+        return "Hi, there. This is a message from first Service.";
+    }
 }

springcloud/second-service/src/main/java/com/example/secondservice/SecondServiceController.java

@@ -21,4 +21,9 @@ public class SecondServiceController {
         log.info(header);
         return "Hello World in Second Service.";
     }
+
+    @GetMapping("/check")
+    public String check() {
+        return "Hi, there. This is a message from Second Service.";
+    }
 }