BAEL-6026 Forward Headers Strategy in Spring Boot

spring-boot-modules/spring-boot-5/src/main/java/com/baeldung/forwardheaders/ForwardHeadersApplication.java

@@ -0,0 +1,12 @@
+package com.baeldung.forwardheaders;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication(scanBasePackages = "com.baeldung.forwardheaders")
+public class ForwardHeadersApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(ForwardHeadersApplication.class, args);
+    }
+}

spring-boot-modules/spring-boot-5/src/main/java/com/baeldung/forwardheaders/TestController.java

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+package com.baeldung.forwardheaders;
+
+import jakarta.servlet.http.HttpServletRequest;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class TestController {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(TestController.class);
+
+    @GetMapping("/test")
+    public ResponseEntity<Void> test(HttpServletRequest request) {
+        LOGGER.info("""
+                scheme : {}
+                Remote Host IP : {}
+                Remote Port : {}
+                Server Name : {}
+                Server Port : {}
+                Request URL : {}""", request.getScheme(), request.getRemoteHost(), request.getRemotePort(), request.getServerName(), request.getServerPort(),
+            request.getRequestURL());
+
+        return new ResponseEntity<>(HttpStatus.OK);
+    }
+}

spring-boot-modules/spring-boot-5/src/main/resources/application-framework.yml

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+server:
+  forward-headers-strategy: FRAMEWORK

spring-boot-modules/spring-boot-5/src/main/resources/application-native.yml

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+server:
+  forward-headers-strategy: NATIVE
+  tomcat:
+    remoteip:
+      remote-ip-header: X-Forwarded-For
+      protocol-header: X-Forwarded-Proto
+      host-header: X-Forwarded-Host
+      port-header: X-Forwarded-Port
+      trusted-proxies: 172\.(1[6-9]|2\d|3[0-1])\.\d{1,3}\.\d{1,3}
+    accesslog:
+      enabled: true
+      request-attributes-enabled: true
+      directory: /app/logs
+      prefix: access_log
+      suffix: .log
+      pattern: '%h %l %u %t "%r" %s %b "%{X-Forwarded-Host}i" "%{X-Forwarded-For}i" "%{X-Forwarded-Proto}i"'
+      rotate: false

spring-boot-modules/spring-boot-5/src/main/resources/application-none.yml

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+server:
+  forward-headers-strategy: NONE

spring-boot-modules/spring-boot-5/src/main/resources/application.yml

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+server:
+  port: 8081
+
+spring:
+  application:
+    name: backend-app

spring-boot-modules/spring-boot-5/src/test/java/com/baeldung/forwardheaders/TestControllerLiveTest.java

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+package com.baeldung.forwardheaders;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.server.LocalServerPort;
+import org.springframework.test.web.servlet.client.RestTestClient;;
+
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+class TestControllerLiveTest {
+
+    private RestTestClient restTestClient;
+
+    @LocalServerPort
+    private int port;
+
+    @BeforeEach
+    void setUp() {
+        restTestClient = RestTestClient
+            .bindToServer()
+            .baseUrl("http://localhost:" + port)
+            .build();
+    }
+
+    @Test
+    void givenTestApiIsRunning_whenGetTestIsCalled_thenReturnOkWithNoContent() {
+        restTestClient.get()
+            .uri("/test")
+            .exchange()
+            .expectStatus().isOk()
+            .expectBody().isEmpty();
+    }
+}

spring-boot-modules/spring-boot-5/src/test/resources/docker/Dockerfile

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+FROM eclipse-temurin:21-jre-alpine
+
+WORKDIR /app
+COPY target/spring-boot-5-0.0.1-SNAPSHOT.jar backend-app.jar
+
+EXPOSE 8081
+ENTRYPOINT ["java", "-jar", "backend-app.jar"]

spring-boot-modules/spring-boot-5/src/test/resources/docker/default/docker-compose.yml

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+services:
+  backend-app:
+    build:
+      context: ../../../../../
+      dockerfile: ./src/test/resources/docker/Dockerfile
+    container_name: backend-app
+    environment:
+      - SPRING_PROFILES_ACTIVE=
+    expose:
+      - "8081"
+
+
+  nginx:
+    image: nginx:1.31.3-alpine
+    container_name: nginx-proxy
+    volumes:
+      - ../../nginx/nginx.conf:/etc/nginx/nginx.conf:ro
+      - ../../nginx/certs:/etc/nginx/certs:ro
+    ports:
+      - "443:443"
+    depends_on:
+      - backend-app
+

spring-boot-modules/spring-boot-5/src/test/resources/docker/framework/docker-compose.yml

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+services:
+  backend-app:
+    build:
+      context: ../../../../../
+      dockerfile: ./src/test/resources/docker/Dockerfile
+    container_name: backend-app
+    environment:
+      - SPRING_PROFILES_ACTIVE=framework
+    expose:
+      - "8081"
+
+  nginx:
+    image: nginx:1.31.3-alpine
+    container_name: nginx-proxy
+    volumes:
+      - ../../nginx/nginx.conf:/etc/nginx/nginx.conf:ro
+      - ../../nginx/certs:/etc/nginx/certs:ro
+    ports:
+      - "443:443"
+    depends_on:
+      - backend-app
+

spring-boot-modules/spring-boot-5/src/test/resources/docker/native/docker-compose.yml

@@ -0,0 +1,22 @@
+services:
+  backend-app:
+    build:
+      context: ../../../../../
+      dockerfile: ./src/test/resources/docker/Dockerfile
+    container_name: backend-app
+    environment:
+      - SPRING_PROFILES_ACTIVE=native
+    expose:
+      - "8081"
+
+  nginx:
+    image: nginx:1.31.3-alpine
+    container_name: nginx-proxy
+    volumes:
+      - ../../nginx/nginx.conf:/etc/nginx/nginx.conf:ro
+      - ../../nginx/certs:/etc/nginx/certs:ro
+    ports:
+      - "443:443"
+    depends_on:
+      - backend-app
+

spring-boot-modules/spring-boot-5/src/test/resources/docker/none/docker-compose.yml

@@ -0,0 +1,23 @@
+services:
+  backend-app:
+    build:
+      context: ../../../../../
+      dockerfile: ./src/test/resources/docker/Dockerfile
+    container_name: backend-app
+    environment:
+      - SPRING_PROFILES_ACTIVE=none
+    expose:
+      - "8081"
+
+
+  nginx:
+    image: nginx:1.31.3-alpine
+    container_name: nginx-proxy
+    volumes:
+      - ../../nginx/nginx.conf:/etc/nginx/nginx.conf:ro
+      - ../../nginx/certs:/etc/nginx/certs:ro
+    ports:
+      - "443:443"
+    depends_on:
+      - backend-app
+

spring-boot-modules/spring-boot-5/src/test/resources/nginx/nginx.conf

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+worker_processes auto;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+
+    map $remote_addr $forwarded_for {
+        ~: "\"[$remote_addr]:$remote_port\"";
+        default "\"$remote_addr:$remote_port\"";
+    }
+
+    map $server_addr $forwarded_by {
+        ~:  "\"[$server_addr]:$server_port\"";
+        default "\"$server_addr:$server_port\"";
+    }
+
+    server {
+        listen 443 ssl;
+        server_name api.example.com;
+
+        ssl_certificate     /etc/nginx/certs/api.example.com.crt;
+        ssl_certificate_key /etc/nginx/certs/api.example.com.key;
+        ssl_protocols TLSv1.2 TLSv1.3;
+
+        location /myapp/ {
+            proxy_pass http://backend-app:8081/;
+
+            proxy_set_header Host $host;
+
+            proxy_set_header X-Forwarded-Proto $scheme;
+            proxy_set_header X-Forwarded-For $remote_addr;
+            proxy_set_header X-Forwarded-Host $host;
+            proxy_set_header X-Forwarded-Port $server_port;
+            proxy_set_header X-Forwarded-Prefix /myapp;
+
+            proxy_set_header Forwarded "for=$forwarded_for;by=$forwarded_by;host=$host;proto=$scheme";
+
+            proxy_http_version 1.1;
+            proxy_set_header Connection "";
+        }
+    }
+}