added filters

firstService/firstService/src/main/java/com/example/firstService/FirstServiceApplication.java → firstService/firstService/src/main/java/com/example/FirstServiceApplication.java

-package com.example.firstService;
+package com.example;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;

firstService/firstService/src/main/java/com/example/controller/FirstController.java

@@ -7,7 +7,8 @@ import org.springframework.web.bind.annotation.*;
 public class FirstController {
 
 	@GetMapping("/message")
-	public String test() {
-		return "Hello JavaInUse Called in First Service";
+	public String test(@RequestHeader("first-request") String header) {
+		System.out.println(header);
+		return "Hello Java Called in First Service";
 	}
 }

gatewayServiceUsingJava/gatewayServiceUsingJava/build.gradle

@@ -13,7 +13,11 @@ repositories {
 }
 
 dependencies {
-	implementation 'org.springframework.boot:spring-boot-starter-web'
+	//implementation 'org.springframework.boot:spring-boot-starter-web'
+
+	compile group: 'org.springframework.boot', name: 'spring-boot-starter', version: '2.2.8.RELEASE'
+	compile group: 'org.springframework.boot', name: 'spring-boot-starter-validation', version: '2.2.8.RELEASE'
+	runtime group: 'org.springframework.cloud', name: 'spring-cloud-dependencies', version: 'Greenwich.SR2', ext: 'pom'
 	compileOnly 'org.projectlombok:lombok'
 	compile group: 'org.springframework.cloud', name: 'spring-cloud-starter-gateway', version: '2.1.5.RELEASE'
 	annotationProcessor 'org.projectlombok:lombok'

gatewayServiceUsingJava/gatewayServiceUsingJava/src/main/java/com/example/gatewayServiceUsingJava/GatewayServiceUsingJavaApplication.java → gatewayServiceUsingJava/gatewayServiceUsingJava/src/main/java/com/example/GatewayServiceUsingJavaApplication.java

-package com.example.gatewayServiceUsingJava;
+package com.example;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.gateway.filter.GlobalFilter;
+import org.springframework.context.annotation.Bean;
+import reactor.core.publisher.Mono;
 
 @SpringBootApplication
 public class GatewayServiceUsingJavaApplication {
 
 	public static void main(String[] args) {
+
 		SpringApplication.run(GatewayServiceUsingJavaApplication.class, args);
 	}
 
+	@Bean
+	public GlobalFilter globalFilter() {
+		return (exchange, chain) -> {
+			System.out.println("First Global filter");
+			return chain.filter(exchange).then(Mono.fromRunnable(() -> {
+				System.out.println("Second Global filter");
+			}));
+		};
+	}
+
 }

gatewayServiceUsingJava/gatewayServiceUsingJava/src/main/java/com/example/config/SpringCloudConfig.java

@@ -12,10 +12,14 @@ public class SpringCloudConfig {
     public RouteLocator gatewayRoutes(RouteLocatorBuilder builder) {
         return builder.routes()
                 .route(r -> r.path("/employee/**")
+                        .filters(f -> f.addRequestHeader("first-request", "first-request-header")
+                                .addResponseHeader("first-response", "first-response-header"))
                         .uri("http://localhost:8081/")
                         .id("employeeModule"))
 
                 .route(r -> r.path("/consumer/**")
+                        .filters(f -> f.addRequestHeader("second-request", "second-request-header")
+                                .addResponseHeader("second-response", "second-response-header"))
                         .uri("http://localhost:8082/")
                         .id("consumerModule"))
                 .build();

gatewayServiceUsingProperties/gatewayServiceUsingProperties/build.gradle

@@ -13,7 +13,10 @@ repositories {
 }
 
 dependencies {
-	implementation 'org.springframework.boot:spring-boot-starter-web'
+
+	compile group: 'org.springframework.boot', name: 'spring-boot-starter', version: '2.2.8.RELEASE'
+	compile group: 'org.springframework.cloud', name: 'spring-cloud-starter-gateway', version: '2.1.5.RELEASE'
+	compile group: 'org.springframework.boot', name: 'spring-boot-starter-validation', version: '2.2.8.RELEASE'
 	compileOnly 'org.projectlombok:lombok'
 	annotationProcessor 'org.projectlombok:lombok'
 	testImplementation('org.springframework.boot:spring-boot-starter-test') {

gatewayServiceUsingProperties/gatewayServiceUsingProperties/src/main/java/com/example/gatewayServiceUsingProperties/GatewayServiceUsingPropertiesApplication.java → gatewayServiceUsingProperties/gatewayServiceUsingProperties/src/main/java/com/example/GatewayServiceUsingPropertiesApplication.java

-package com.example.gatewayServiceUsingProperties;
+package com.example;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;

gatewayServiceUsingProperties/gatewayServiceUsingProperties/src/main/java/com/example/config/CustomFilter.java

+package com.example.config;
+
+import org.springframework.cloud.gateway.filter.GatewayFilter;
+import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
+import org.springframework.stereotype.Component;
+import reactor.core.publisher.Mono;
+
+@Component
+public class CustomFilter extends AbstractGatewayFilterFactory<CustomFilter.Config> {
+    public CustomFilter() {
+        super(Config.class);
+    }
+
+    @Override
+    public GatewayFilter apply(Config config) {
+        //Custom Pre Filter. Suppose we can extract JWT and perform Authentication
+        return (exchange, chain) -> {
+            System.out.println("First pre filter" + exchange.getRequest());
+            //Custom Post Filter.Suppose we can call error response handler based on error code.
+            return chain.filter(exchange).then(Mono.fromRunnable(() -> {
+                System.out.println("First post filter");
+            }));
+        };
+    }
+
+    public static class Config {
+        // Put the configuration properties
+    }
+}

gatewayServiceUsingProperties/gatewayServiceUsingProperties/src/main/resources/application.yml

@@ -4,6 +4,8 @@ server:
 spring:
   cloud:
     gateway:
+      default-filters:
+        - name: CustomFilter
       routes:
       - id: employeeModule
         uri: http://localhost:8081/

secondService/secondService/src/main/java/com/example/secondService/SecondServiceApplication.java → secondService/secondService/src/main/java/com/example/SecondServiceApplication.java

-package com.example.secondService;
+package com.example;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
@@ -7,6 +7,7 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 public class SecondServiceApplication {
 
 	public static void main(String[] args) {
+
 		SpringApplication.run(SecondServiceApplication.class, args);
 	}
 

secondService/secondService/src/main/java/com/example/controller/SecondController.java

 package com.example.controller;
 
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestHeader;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
@@ -9,8 +10,9 @@ import org.springframework.web.bind.annotation.RestController;
 public class SecondController {
 
     @GetMapping("/message")
-    public String test(){
-        return "Hello JavaInUse Called in Second Service";
+    public String test(@RequestHeader("second-request") String header) {
+        System.out.println(header);
+        return "Hello Java Called in Second Service";
     }
 
 }