Add RemoveRequestHeader 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.RemoveRequestHeaderFilterFactory;
 import org.springframework.cloud.gateway.filter.factory.RewritePathFilterFactory;
 import org.springframework.cloud.gateway.handler.GatewayFilteringWebHandler;
 import org.springframework.cloud.gateway.handler.GatewayPredicateHandlerMapping;
@@ -121,6 +122,11 @@ public class GatewayAutoConfiguration {
 		return new AddResponseHeaderFilterFactory();
 	}
 
+	@Bean
+	public RemoveRequestHeaderFilterFactory removeRequestHeaderFilterFactory() {
+		return new RemoveRequestHeaderFilterFactory();
+	}
+
 	@Bean
 	public RewritePathFilterFactory rewritePathFilterFactory() {
 		return new RewritePathFilterFactory();

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

@@ -27,4 +27,13 @@ public class OrderedGatewayFilter implements GatewayFilter, Ordered {
 	public int getOrder() {
 		return this.order;
 	}
+
+	@Override
+	public String toString() {
+		final StringBuilder sb = new StringBuilder("OrderedGatewayFilter{");
+		sb.append("delegate=").append(delegate);
+		sb.append(", order=").append(order);
+		sb.append('}');
+		return sb.toString();
+	}
 }

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

@@ -0,0 +1,28 @@
+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 RemoveRequestHeaderFilterFactory implements FilterFactory {
+
+	public static final String FAKE_HEADER = "_______force_______";
+
+	@Override
+	public GatewayFilter apply(String header, String[] args) {
+
+		//TODO: caching can happen here
+		return (exchange, chain) -> {
+			ServerHttpRequest request = exchange.getRequest().mutate()
+					.header(FAKE_HEADER, "mutable") //TODO: is there a better way?
+					.build();
+
+			request.getHeaders().remove(FAKE_HEADER);
+			request.getHeaders().remove(header);
+
+			return chain.filter(exchange.mutate().request(request).build());
+		};
+	}
+}

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

@@ -149,10 +149,11 @@ public class GatewayIntegrationTests {
 	}
 
 	@Test
+	@SuppressWarnings("unchecked")
 	public void addRequestHeaderFilterWorks() {
 		Mono<Map> result = webClient.exchange(
 				GET("http://localhost:" + port + "/headers")
-						.header("Host", "www.bar.org")
+						.header("Host", "www.addrequestheader.org")
 						.build()
 		).then(response -> response.body(toMono(Map.class)));
 
@@ -169,6 +170,29 @@ public class GatewayIntegrationTests {
 		);
 	}
 
+	@Test
+	@SuppressWarnings("unchecked")
+	public void removeRequestHeaderFilterWorks() {
+		Mono<Map> result = webClient.exchange(
+				GET("http://localhost:" + port + "/headers")
+						.header("Host", "www.removerequestheader.org")
+						.header("X-Request-Foo", "Bar")
+						.build()
+		).then(response -> response.body(toMono(Map.class)));
+
+		verify( () ->
+				StepVerifier.create(result)
+						.consumeNextWith(
+								response -> {
+									assertThat(response).containsKey("headers").isInstanceOf(Map.class);
+									Map<String, Object> headers = (Map<String, Object>) response.get("headers");
+									assertThat(headers).doesNotContainKey("X-Request-Foo");
+								})
+						.expectComplete()
+						.verify(Duration.ofSeconds(3))
+		);
+	}
+
 	@Test
 	public void postWorks() {
 		ClientRequest<Mono<String>> request = POST("http://localhost:" + port + "/post")
@@ -222,7 +246,7 @@ public class GatewayIntegrationTests {
 		private static final Log log = LogFactory.getLog(TestConfig.class);
 
 		@Bean
-		@Order(501)
+		@Order(500)
 		public GatewayFilter modifyResponseFilter() {
 			return (exchange, chain) -> {
 				log.info("modifyResponseFilter start");
@@ -237,7 +261,7 @@ public class GatewayIntegrationTests {
 		}
 
 		@Bean
-		@Order(502)
+		@Order(-1)
 		public GatewayFilter postFilter() {
 			return (exchange, chain) -> {
 				log.info("postFilter start");

src/test/resources/application.yml

@@ -24,11 +24,20 @@ spring:
       - id: add_request_header_test
         uri: http://httpbin.org:80
         predicates:
-        - Host=**.bar.org
+        - Host=**.addrequestheader.org
         - Url=/headers
         filters:
         - AddRequestHeader=X-Request-Foo, Bar
 
+      # =====================================
+      - id: remove_request_header_test
+        uri: http://httpbin.org:80
+        predicates:
+        - Host=**.removerequestheader.org
+        - Url=/headers
+        filters:
+        - RemoveRequestHeader=X-Request-Foo
+
       # =====================================
       - id: rewrite_path_test
         uri: http://httpbin.org:80