From 779187e6ae92f65bda49b0829da521601b28fac2 Mon Sep 17 00:00:00 2001
From: Dennis Menge <dmenge@me.com>
Date: Thu, 1 Oct 2020 17:20:07 +0200
Subject: [PATCH] Allows multiple values applied with
 AddRequestHeaderGatewayFilterFactory

Fixes gh-1902
---
 .../AddRequestHeaderGatewayFilterFactory.java |  2 +-
 ...equestHeaderGatewayFilterFactoryTests.java | 30 +++++++++++++++++--
 .../application-request-header-web-filter.yml | 11 +++++--
 3 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/filter/factory/AddRequestHeaderGatewayFilterFactory.java b/spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/filter/factory/AddRequestHeaderGatewayFilterFactory.java
index b7a3708b..6966af70 100644
--- a/spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/filter/factory/AddRequestHeaderGatewayFilterFactory.java
+++ b/spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/filter/factory/AddRequestHeaderGatewayFilterFactory.java
@@ -40,7 +40,7 @@ public class AddRequestHeaderGatewayFilterFactory
 					GatewayFilterChain chain) {
 				String value = ServerWebExchangeUtils.expand(exchange, config.getValue());
 				ServerHttpRequest request = exchange.getRequest().mutate()
-						.header(config.getName(), value).build();
+						.headers(httpHeaders -> httpHeaders.add(config.getName(), value)).build();
 
 				return chain.filter(exchange.mutate().request(request).build());
 			}
diff --git a/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/filter/factory/AddRequestHeaderGatewayFilterFactoryTests.java b/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/filter/factory/AddRequestHeaderGatewayFilterFactoryTests.java
index ddb8792c..4736f1dd 100644
--- a/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/filter/factory/AddRequestHeaderGatewayFilterFactoryTests.java
+++ b/spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/filter/factory/AddRequestHeaderGatewayFilterFactoryTests.java
@@ -16,6 +16,7 @@
 
 package org.springframework.cloud.gateway.filter.factory;
 
+import java.util.Arrays;
 import java.util.Map;
 
 import org.junit.Test;
@@ -60,6 +61,16 @@ public class AddRequestHeaderGatewayFilterFactoryTests extends BaseWebClientTest
 				});
 	}
 
+	@Test
+	public void addRequestHeaderFilterWorksMultipleValues() {
+		testClient.get().uri("/multivalueheaders").header("Host", "www.addrequestheader.org").exchange()
+				.expectBody(Map.class)
+				.consumeWith(result -> {
+					Map<String, Object> headers = getMap(result.getResponseBody(), "headers");
+					assertThat(headers).containsEntry("X-Request-Example", Arrays.asList("ValueA", "ValueB"));
+				});
+	}
+
 	@Test
 	public void addRequestHeaderFilterWorksJavaDsl() {
 		testClient.get().uri("/headers").header("Host", "www.addrequestheaderjava.org")
@@ -70,6 +81,16 @@ public class AddRequestHeaderGatewayFilterFactoryTests extends BaseWebClientTest
 				});
 	}
 
+	@Test
+	public void addRequestHeaderFilterMultipleValuesWorksJavaDsl() {
+		testClient.get().uri("/multivalueheaders").header("Host", "www.addrequestheaderjava.org").exchange()
+				.expectBody(Map.class)
+				.consumeWith(result -> {
+					Map<String, Object> headers = getMap(result.getResponseBody(), "headers");
+					assertThat(headers).containsEntry("X-Request-Acme", Arrays.asList("ValueB-www", "ValueC-www"));
+				});
+	}
+
 	@Test
 	public void toStringFormat() {
 		NameValueConfig config = new NameValueConfig().setName("myname")
@@ -90,9 +111,14 @@ public class AddRequestHeaderGatewayFilterFactoryTests extends BaseWebClientTest
 		public RouteLocator testRouteLocator(RouteLocatorBuilder builder) {
 			return builder.routes().route("add_request_header_java_test",
 					r -> r.path("/headers").and().host("{sub}.addrequestheaderjava.org")
-							.filters(f -> f.prefixPath("/httpbin")
-									.addRequestHeader("X-Request-Acme", "ValueB-{sub}"))
+							.filters(f -> f.prefixPath("/httpbin").addRequestHeader("X-Request-Acme", "ValueB-{sub}"))
 							.uri(uri))
+					.route("add_multiple_request_header_java_test",
+							r -> r.path("/multivalueheaders").and().host("{sub}.addrequestheaderjava.org")
+									.filters(f -> f.prefixPath("/httpbin")
+											.addRequestHeader("X-Request-Acme", "ValueB-{sub}")
+											.addRequestHeader("X-Request-Acme", "ValueC-{sub}"))
+									.uri(uri))
 					.build();
 		}
 
diff --git a/spring-cloud-gateway-server/src/test/resources/application-request-header-web-filter.yml b/spring-cloud-gateway-server/src/test/resources/application-request-header-web-filter.yml
index 3778f9a4..021ac0af 100644
--- a/spring-cloud-gateway-server/src/test/resources/application-request-header-web-filter.yml
+++ b/spring-cloud-gateway-server/src/test/resources/application-request-header-web-filter.yml
@@ -5,6 +5,13 @@ spring:
       - id: add_request_header_test
         uri: ${test.uri}
         predicates:
-        - Path=/headers
+          - Path=/headers
         filters:
-        - AddRequestHeader=X-Request-Example, ValueA
+          - AddRequestHeader=X-Request-Example, ValueA
+      - id: add_multiple_request_header_test
+        uri: ${test.uri}
+        predicates:
+          - Path=/multivalueheaders
+        filters:
+          - AddRequestHeader=X-Request-Example, ValueA
+          - AddRequestHeader=X-Request-Example, ValueB