Bael 5259 (#11832)

* [BAEL-4849] Article code

* [BAEL-4968] Article code

* [BAEL-4968] Article code

* [BAEL-4968] Article code

* [BAEL-4968] Remove extra comments

* [BAEL-5259] simple test case

* [BAEL-5259] DSL-based rewrite

* [BAEL-5259] Code formatting

* [BAEL-5259] Test case naming

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

@@ -177,5 +177,21 @@
                 </plugins>
             </build>
         </profile>
+        
+        <profile>
+            <id>gateway-url-rewrite</id>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.springframework.boot</groupId>
+                        <artifactId>spring-boot-maven-plugin</artifactId>
+                        <configuration>
+                            <mainClass>com.baeldung.springcloudgateway.rewrite.URLRewriteGatewayApplication</mainClass>
+                            <jvmArguments>-Dspring.profiles.active=url-rewrite</jvmArguments>
+                        </configuration>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>        
     </profiles>
 </project>

spring-cloud/spring-cloud-gateway/src/main/java/com/baeldung/springcloudgateway/rewrite/URLRewriteGatewayApplication.java

@@ -0,0 +1,25 @@
+/**
+ * 
+ */
+package com.baeldung.springcloudgateway.rewrite;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.cloud.gateway.filter.GatewayFilter;
+
+import reactor.core.publisher.Mono;
+
+/**
+ * @author Baeldung
+ *
+ */
+@SpringBootApplication
+public class URLRewriteGatewayApplication {
+    
+    public static void main(String[] args) {
+        new SpringApplicationBuilder(URLRewriteGatewayApplication.class)
+          .profiles("url-rewrite")
+          .run(args);
+    }
+    
+}

spring-cloud/spring-cloud-gateway/src/main/java/com/baeldung/springcloudgateway/rewrite/routes/DynamicRewriteRoute.java

@@ -0,0 +1,43 @@
+package com.baeldung.springcloudgateway.rewrite.routes;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.cloud.gateway.route.RouteLocator;
+import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Profile;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+
+import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR;
+import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.addOriginalRequestUrl;
+
+import java.util.Random;
+
+@Configuration
+@Profile("url-rewrite")
+public class DynamicRewriteRoute {
+    
+    @Value("${rewrite.backend.uri}")
+    private String backendUri;
+    private static Random rnd = new Random();
+    
+    @Bean
+    public RouteLocator dynamicZipCodeRoute(RouteLocatorBuilder builder) {
+        return builder.routes()
+          .route("dynamicRewrite", r ->
+             r.path("/v2/zip/**")
+              .filters(f -> f.filter((exchange, chain) -> {
+                  ServerHttpRequest req = exchange.getRequest();
+                  addOriginalRequestUrl(exchange, req.getURI());
+                  String path = req.getURI().getRawPath();
+                  String newPath = path.replaceAll(
+                    "/v2/zip/(?<zipcode>.*)", 
+                    "/api/zip/${zipcode}-" + String.format("%03d", rnd.nextInt(1000)));
+                  ServerHttpRequest request = req.mutate().path(newPath).build();
+                  exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, request.getURI());
+                  return chain.filter(exchange.mutate().request(request).build());
+              }))
+              .uri(backendUri))
+          .build();
+    }
+}

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

@@ -8,7 +8,7 @@ public class WebFilterGatewayApplication {
 
     public static void main(String[] args) {
         new SpringApplicationBuilder(WebFilterGatewayApplication.class)
-          .profiles("webfilters")
+          .profiles("url-rewrite")
           .run(args);
     }
 

spring-cloud/spring-cloud-gateway/src/main/resources/application-nosecurity.yml

@@ -0,0 +1,8 @@
+# Enable this profile to disable security
+spring:
+  autoconfigure:
+    exclude:
+     - org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration
+     - org.springframework.boot.actuate.autoconfigure.ManagementSecurityAutoConfiguration
+     - org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration
+     - org.springframework.boot.actuate.autoconfigure.security.reactive.ReactiveManagementWebSecurityAutoConfiguration

spring-cloud/spring-cloud-gateway/src/main/resources/application-url-rewrite.yml

@@ -0,0 +1,11 @@
+spring:
+  cloud:
+    gateway:
+      routes:
+      - id: rewrite_v1
+        uri: ${rewrite.backend.uri:http://example.com}
+        predicates:
+        - Path=/v1/customer/**
+        filters:
+        - RewritePath=/v1/customer/(?<segment>.*),/api/$\{segment}
+        

spring-cloud/spring-cloud-gateway/src/test/java/com/baeldung/springcloudgateway/rewrite/URLRewriteGatewayApplicationLiveTest.java

@@ -0,0 +1,109 @@
+package com.baeldung.springcloudgateway.rewrite;
+
+import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.OutputStream;
+import java.net.InetSocketAddress;
+
+import org.junit.AfterClass;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.web.server.LocalServerPort;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.context.DynamicPropertyRegistry;
+import org.springframework.test.context.DynamicPropertySource;
+import org.springframework.test.web.reactive.server.WebTestClient;
+
+import com.sun.net.httpserver.HttpServer;
+
+@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
+@ActiveProfiles({ "nosecurity", "url-rewrite" })
+class URLRewriteGatewayApplicationLiveTest {
+
+    // NOTE for Eclipse users: By default, Eclipse will complain about com.sun.** classes.
+    // To solve this issue, follow instructions available at the :
+    // https://stackoverflow.com/questions/13155734/eclipse-cant-recognize-com-sun-net-httpserver-httpserver-package
+    private static HttpServer mockServer;
+    private static Logger log = LoggerFactory.getLogger(URLRewriteGatewayApplicationLiveTest.class);
+
+    // Create a running HttpServer that echoes back the request URL.
+    private static HttpServer startTestServer() {
+
+        try {
+            log.info("[I26] Starting mock server");
+            mockServer = HttpServer.create();
+            mockServer.bind(new InetSocketAddress(0), 0);
+            mockServer.createContext("/api", (xchg) -> {
+                String uri = xchg.getRequestURI()
+                    .toString();
+                log.info("[I23] Backend called: uri={}", uri);
+                xchg.getResponseHeaders()
+                    .add("Content-Type", "text/plain");
+                xchg.sendResponseHeaders(200, 0);
+                OutputStream os = xchg.getResponseBody();
+                os.write(uri.getBytes());
+                os.flush();
+                os.close();
+            });
+
+            mockServer.start();
+            InetSocketAddress localAddr = mockServer.getAddress();
+            log.info("[I36] mock server started: local address={}", localAddr);
+            
+            return mockServer;
+        } catch (Exception ex) {
+            throw new RuntimeException(ex);
+        }
+
+    }
+
+    // TIP: https://www.baeldung.com/spring-dynamicpropertysource
+    @DynamicPropertySource
+    static void registerBackendServer(DynamicPropertyRegistry registry) {
+        registry.add("rewrite.backend.uri", () -> {
+            HttpServer s = startTestServer();
+            return "http://localhost:" + s.getAddress().getPort();
+        });
+    }
+
+    @AfterClass
+    public static void stopMockBackend() throws Exception {
+        log.info("[I40] Shutdown mock http server");
+        mockServer.stop(5);
+    }
+
+    @LocalServerPort
+    private int localPort;
+
+    @Test
+    void testWhenApiCall_thenRewriteSuccess(@Autowired WebTestClient webClient) {
+        webClient.get()
+          .uri("http://localhost:" + localPort + "/v1/customer/customer1")
+          .exchange()
+          .expectBody()
+          .consumeWith((result) -> {
+              String body = new String(result.getResponseBody());
+              log.info("[I99] body={}", body);
+              assertEquals("/api/customer1", body);
+          });
+    }
+
+    @Test
+    void testWhenDslCall_thenRewriteSuccess(@Autowired WebTestClient webClient) {
+        webClient.get()
+          .uri("http://localhost:" + localPort + "/v2/zip/123456")
+          .exchange()
+          .expectBody()
+          .consumeWith((result) -> {
+              String body = new String(result.getResponseBody());
+              log.info("[I99] body={}", body);
+              assertTrue(body.matches("/api/zip/123456-\\d{3}"));
+          });
+    }
+    
+}