Added RewritePath filter

src/main/java/org/springframework/cloud/gateway/config/GatewayAutoConfiguration.java

@@ -13,6 +13,7 @@ import org.springframework.cloud.gateway.filter.factory.AddRequestHeaderFilterFa
 import org.springframework.cloud.gateway.filter.factory.AddResponseHeaderFilterFactory;
 import org.springframework.cloud.gateway.filter.factory.FilterFactory;
 import org.springframework.cloud.gateway.filter.RouteToRequestUrlFilter;
+import org.springframework.cloud.gateway.filter.factory.RewritePathFilterFactory;
 import org.springframework.cloud.gateway.handler.GatewayFilteringWebHandler;
 import org.springframework.cloud.gateway.handler.GatewayPredicateHandlerMapping;
 import org.springframework.cloud.gateway.handler.GatewayWebHandler;
@@ -120,6 +121,11 @@ public class GatewayAutoConfiguration {
 		return new AddResponseHeaderFilterFactory();
 	}
 
+	@Bean
+	public RewritePathFilterFactory rewritePathFilterFactory() {
+		return new RewritePathFilterFactory();
+	}
+
 	@Configuration
 	@ConditionalOnClass(Endpoint.class)
 	protected static class GatewayActuatorConfiguration {

src/main/java/org/springframework/cloud/gateway/filter/OrderedGatewayFilter.java

@@ -0,0 +1,30 @@
+package org.springframework.cloud.gateway.filter;
+
+import org.springframework.core.Ordered;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.WebFilterChain;
+import reactor.core.publisher.Mono;
+
+/**
+ * @author Spencer Gibb
+ */
+public class OrderedGatewayFilter implements GatewayFilter, Ordered {
+
+	private final GatewayFilter delegate;
+	private final int order;
+
+	public OrderedGatewayFilter(GatewayFilter delegate, int order) {
+		this.delegate = delegate;
+		this.order = order;
+	}
+
+	@Override
+	public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
+		return this.delegate.filter(exchange, chain);
+	}
+
+	@Override
+	public int getOrder() {
+		return this.order;
+	}
+}

src/main/java/org/springframework/cloud/gateway/filter/RouteToRequestUrlFilter.java

@@ -18,7 +18,7 @@ import reactor.core.publisher.Mono;
 public class RouteToRequestUrlFilter implements GatewayFilter, Ordered {
 
 	private static final Log log = LogFactory.getLog(RouteToRequestUrlFilter.class);
-	public static final int ROUTE_TO_URL_FILTER_ORDER = 500;
+	public static final int ROUTE_TO_URL_FILTER_ORDER = 10000;
 
 	@Override
 	public int getOrder() {

src/main/java/org/springframework/cloud/gateway/filter/factory/AddRequestHeaderFilterFactory.java

@@ -2,22 +2,15 @@ package org.springframework.cloud.gateway.filter.factory;
 
 import org.springframework.cloud.gateway.filter.GatewayFilter;
 import org.springframework.http.server.reactive.ServerHttpRequest;
-import org.springframework.util.Assert;
 
 /**
  * @author Spencer Gibb
  */
 public class AddRequestHeaderFilterFactory implements FilterFactory {
 
-	@Override
-	public String getName() {
-		return "AddRequestHeader";
-	}
-
 	@Override
 	public GatewayFilter apply(String header, String[] args) {
-		Assert.isTrue(args != null && args.length == 1,
-				"args must have one entry");
+		validate(args, 1);
 
 		//TODO: caching can happen here
 		return (exchange, chain) -> {

src/main/java/org/springframework/cloud/gateway/filter/factory/AddResponseHeaderFilterFactory.java

@@ -1,22 +1,15 @@
 package org.springframework.cloud.gateway.filter.factory;
 
 import org.springframework.cloud.gateway.filter.GatewayFilter;
-import org.springframework.util.Assert;
 
 /**
  * @author Spencer Gibb
  */
 public class AddResponseHeaderFilterFactory implements FilterFactory {
 
-	@Override
-	public String getName() {
-		return "AddResponseHeader";
-	}
-
 	@Override
 	public GatewayFilter apply(String header, String[] args) {
-		Assert.isTrue(args != null && args.length == 1,
-				"args must have one entry");
+		validate(args, 1);
 
 		//TODO: caching can happen here
 		return (exchange, chain) -> {

src/main/java/org/springframework/cloud/gateway/filter/factory/FilterFactory.java

@@ -1,13 +1,21 @@
 package org.springframework.cloud.gateway.filter.factory;
 
 import org.springframework.cloud.gateway.filter.GatewayFilter;
+import org.springframework.util.Assert;
 
 /**
  * @author Spencer Gibb
  */
 public interface FilterFactory {
 
-	String getName();
+	default String getName() {
+		return getClass().getSimpleName().replace(FilterFactory.class.getSimpleName(), "");
+	}
 
 	GatewayFilter apply(String value, String[] args);
+
+	default void validate(String[] args, int requiredSize) {
+		Assert.isTrue(args != null && args.length == requiredSize,
+				"args must have "+ requiredSize +" entry(s)");
+	}
 }

src/main/java/org/springframework/cloud/gateway/filter/factory/RewritePathFilterFactory.java

@@ -0,0 +1,29 @@
+package org.springframework.cloud.gateway.filter.factory;
+
+import org.springframework.cloud.gateway.filter.GatewayFilter;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+
+/**
+ * @author Spencer Gibb
+ */
+public class RewritePathFilterFactory implements FilterFactory {
+
+	@Override
+	public GatewayFilter apply(String regex, String[] args) {
+		validate(args, 1);
+		String replacement = args[0].replace("$\\", "$");
+
+		//TODO: caching can happen here
+		return (exchange, chain) -> {
+			ServerHttpRequest req = exchange.getRequest();
+			String path = req.getURI().getPath();
+			String newPath = path.replaceAll(regex, replacement);
+
+			ServerHttpRequest request = req.mutate()
+					.path(newPath)
+					.build();
+
+			return chain.filter(exchange.mutate().request(request).build());
+		};
+	}
+}

src/main/java/org/springframework/cloud/gateway/handler/GatewayFilteringWebHandler.java

@@ -18,7 +18,6 @@ package org.springframework.cloud.gateway.handler;
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
@@ -30,17 +29,19 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.cloud.gateway.config.Route;
 import org.springframework.cloud.gateway.filter.GatewayFilter;
+import org.springframework.cloud.gateway.filter.OrderedGatewayFilter;
 import org.springframework.cloud.gateway.filter.factory.FilterFactory;
+import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebFilterChain;
 import org.springframework.web.server.WebHandler;
 import org.springframework.web.server.handler.WebHandlerDecorator;
 
-import reactor.core.publisher.Mono;
-
 import static java.util.Collections.emptyList;
 import static org.springframework.cloud.gateway.filter.GatewayFilter.GATEWAY_ROUTE_ATTR;
 
+import reactor.core.publisher.Mono;
+
 /**
  * WebHandler that delegates to a chain of {@link GatewayFilter} instances and then
  * to the target {@link WebHandler}.
@@ -76,15 +77,19 @@ public class GatewayFilteringWebHandler extends WebHandlerDecorator {
 	public Mono<Void> handle(ServerWebExchange exchange) {
 		//TODO: probably a java 8 stream way of doing this
 		ArrayList<GatewayFilter> routeFilters = new ArrayList<>(this.filters);
+
 		Optional<Route> route = exchange.getAttribute(GATEWAY_ROUTE_ATTR);
 		if (route.isPresent() && !route.get().getFilters().isEmpty()) {
 			routeFilters.addAll(loadFilters(route.get()));
 		}
+
+		AnnotationAwareOrderComparator.sort(routeFilters);
+
 		return new DefaultWebFilterChain(routeFilters, getDelegate()).filter(exchange);
 	}
 
-	private Collection<GatewayFilter> loadFilters(Route route) {
-		return route.getFilters().stream()
+	private List<GatewayFilter> loadFilters(Route route) {
+		List<GatewayFilter> filters = route.getFilters().stream()
 				.map(definition -> {
 					FilterFactory filter = this.filterDefinitions.get(definition.getName());
 					if (filter == null) {
@@ -97,12 +102,19 @@ public class GatewayFilteringWebHandler extends WebHandlerDecorator {
 						} else {
 							args = Collections.emptyList();
 						}
-						logger.debug("Route " + route.getId() + " applying filter "+ definition.getValue()
+						logger.debug("Route " + route.getId() + " applying filter " + definition.getValue()
 								+ ", " + args + " to " + definition.getName());
 					}
 					return filter.apply(definition.getValue(), definition.getArgs());
 				})
 				.collect(Collectors.toList());
+
+		ArrayList<GatewayFilter> ordered = new ArrayList<>(filters.size());
+		for (int i = 0; i < filters.size(); i++) {
+			ordered.add(new OrderedGatewayFilter(filters.get(i), i+1));
+		}
+
+		return ordered;
 	}
 
 

src/test/java/org/springframework/cloud/gateway/filter/factory/RewritePathFilterFactoryTests.java

@@ -0,0 +1,52 @@
+package org.springframework.cloud.gateway.filter.factory;
+
+import org.assertj.core.api.Assertions;
+import org.junit.Test;
+import org.mockito.ArgumentCaptor;
+import org.springframework.cloud.gateway.filter.GatewayFilter;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.MockServerHttpResponse;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.WebFilterChain;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import reactor.core.publisher.Mono;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * @author Spencer Gibb
+ */
+public class RewritePathFilterFactoryTests {
+
+	@Test
+	public void rewritePathFilterWorks() {
+		testRewriteFilter("/foo", "/baz", "/foo/bar", "/baz/bar");
+	}
+
+	@Test
+	public void rewritePathFilterWithNamedGroupWorks() {
+		testRewriteFilter("/foo/(?<id>\\d.*)", "/bar/baz/$\\{id}", "/foo/123", "/bar/baz/123");
+	}
+
+	private void testRewriteFilter(String regex, String replacement, String actualPath, String expectedPath) {
+		GatewayFilter filter = new RewritePathFilterFactory().apply(regex, new String[]{replacement});
+
+		MockServerHttpRequest request = MockServerHttpRequest
+				.get("http://localhost"+ actualPath)
+				.build();
+
+		DefaultServerWebExchange exchange = new DefaultServerWebExchange(request, new MockServerHttpResponse());
+
+		WebFilterChain filterChain = mock(WebFilterChain.class);
+
+		ArgumentCaptor<ServerWebExchange> captor = ArgumentCaptor.forClass(ServerWebExchange.class);
+		when(filterChain.filter(captor.capture())).thenReturn(Mono.empty());
+
+		filter.filter(exchange, filterChain);
+
+		ServerWebExchange webExchange = captor.getValue();
+
+		Assertions.assertThat(webExchange.getRequest().getURI().getPath()).isEqualTo(expectedPath);
+	}
+}

src/test/java/org/springframework/cloud/gateway/test/GatewayIntegrationTests.java

@@ -128,6 +128,26 @@ public class GatewayIntegrationTests {
 		);
 	}
 
+	@Test
+	public void rewritePathFilterWorks() {
+		Mono<ClientResponse> result = webClient.exchange(
+				GET("http://localhost:" + port + "/foo/get")
+						.header("Host", "www.baz.org")
+						.build()
+		);
+
+		verify( () ->
+				StepVerifier.create(result)
+						.consumeNextWith(
+								response -> {
+									HttpStatus statusCode = response.statusCode();
+									assertThat(statusCode).isEqualTo(HttpStatus.OK);
+								})
+						.expectComplete()
+						.verify(Duration.ofSeconds(3))
+		);
+	}
+
 	@Test
 	public void addRequestHeaderFilterWorks() {
 		Mono<Map> result = webClient.exchange(

src/test/resources/application.yml

@@ -21,7 +21,7 @@ spring:
         - AddResponseHeader=X-Response-Foo, Bar
 
       # =====================================
-      - id: host_bar_path_headers_to_httpbin
+      - id: add_request_header_test
         uri: http://httpbin.org:80
         predicates:
         - Host=**.bar.org
@@ -29,6 +29,17 @@ spring:
         filters:
         - AddRequestHeader=X-Request-Foo, Bar
 
+      # =====================================
+      - id: rewrite_path_test
+        uri: http://httpbin.org:80
+        predicates:
+        - Host=**.baz.org
+        filters:
+        # $\ is being used as an escape
+        - RewritePath=/foo/(?<segment>.*), /$\{segment}
+        - AddRequestHeader=X-Request-Foo, Bar
+        - AddRequestHeader=X-Request-Baz, Bat
+
       # =====================================
       - id: default_path_to_httpbin
         uri: http://httpbin.org:80