Adds AddRequestParameter

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

@@ -13,6 +13,7 @@ import org.springframework.cloud.gateway.filter.GlobalFilter;
 import org.springframework.cloud.gateway.filter.RouteToRequestUrlFilter;
 import org.springframework.cloud.gateway.filter.WriteResponseFilter;
 import org.springframework.cloud.gateway.filter.route.AddRequestHeaderRouteFilter;
+import org.springframework.cloud.gateway.filter.route.AddRequestParameterRouteFilter;
 import org.springframework.cloud.gateway.filter.route.AddResponseHeaderRouteFilter;
 import org.springframework.cloud.gateway.filter.route.RemoveRequestHeaderRouteFilter;
 import org.springframework.cloud.gateway.filter.route.RemoveResponseHeaderRouteFilter;
@@ -130,6 +131,11 @@ public class GatewayAutoConfiguration {
 		return new AddRequestHeaderRouteFilter();
 	}
 
+	@Bean(name = "AddRequestParameterRouteFilter")
+	public AddRequestParameterRouteFilter addRequestParameterRouteFilter() {
+		return new AddRequestParameterRouteFilter();
+	}
+
 	@Bean(name = "AddResponseHeaderRouteFilter")
 	public AddResponseHeaderRouteFilter addResponseHeaderRouteFilter() {
 		return new AddResponseHeaderRouteFilter();

src/main/java/org/springframework/cloud/gateway/filter/route/AddRequestParameterRouteFilter.java

@@ -0,0 +1,138 @@
+package org.springframework.cloud.gateway.filter.route;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+import org.springframework.web.server.WebFilter;
+
+/**
+ * @author Spencer Gibb
+ */
+public class AddRequestParameterRouteFilter implements RouteFilter {
+
+	@Override
+	public WebFilter apply(String parameter, String[] args) {
+		validate(args, 1);
+
+		//TODO: caching can happen here
+		return (exchange, chain) -> {
+
+			URI uri = exchange.getRequest().getURI();
+			StringBuilder query = new StringBuilder();
+			String originalQuery = uri.getQuery();
+
+			if (StringUtils.hasText(originalQuery)) {
+				query.append(originalQuery);
+				if (originalQuery.charAt(originalQuery.length() - 1) != '&') {
+					query.append('&');
+				}
+			}
+
+			//TODO urlencode?
+			query.append(parameter);
+			query.append('=');
+			query.append(args[0]);
+
+			ServerHttpRequest request = new QueryParamServerHttpRequestBuilder(exchange.getRequest())
+					.query(query.toString())
+					.build();
+
+			return chain.filter(exchange.mutate().request(request).build());
+		};
+	}
+
+	class QueryParamServerHttpRequestBuilder implements ServerHttpRequest.Builder {
+
+		private final ServerHttpRequest delegate;
+		private String query;
+
+		public QueryParamServerHttpRequestBuilder(ServerHttpRequest delegate) {
+			Assert.notNull(delegate, "ServerHttpRequest delegate is required");
+			this.delegate = delegate;
+		}
+
+
+		@Override
+		public ServerHttpRequest.Builder method(HttpMethod httpMethod) {
+			throw new UnsupportedOperationException();
+		}
+
+		@Override
+		public ServerHttpRequest.Builder path(String path) {
+			throw new UnsupportedOperationException();
+		}
+
+		public ServerHttpRequest.Builder query(String query) {
+			this.query = query;
+			return this;
+		}
+
+		@Override
+		public ServerHttpRequest.Builder contextPath(String contextPath) {
+			throw new UnsupportedOperationException();
+		}
+
+		@Override
+		public ServerHttpRequest.Builder header(String key, String value) {
+			throw new UnsupportedOperationException();
+		}
+
+		@Override
+		public ServerHttpRequest build() {
+			URI uri = null;
+			if (this.query != null) {
+				uri = this.delegate.getURI();
+				try {
+					uri = new URI(uri.getScheme(), uri.getUserInfo(), uri.getHost(), uri.getPort(),
+							uri.getPath(), this.query, uri.getFragment());
+				} catch (URISyntaxException ex) {
+					throw new IllegalStateException("Invalid URI query: \"" + this.query + "\"");
+				}
+			}
+			return new MutativeDecorator(this.delegate, uri);
+		}
+
+
+		/**
+		 * An immutable wrapper of a request returning property overrides -- given
+		 * to the constructor -- or original values otherwise.
+		 */
+		private class MutativeDecorator extends ServerHttpRequestDecorator {
+
+			private final URI uri;
+
+			public MutativeDecorator(ServerHttpRequest delegate, URI uri) {
+				super(delegate);
+
+				this.uri = uri;
+			}
+
+			@Override
+			public HttpMethod getMethod() {
+				return super.getMethod();
+			}
+
+			@Override
+			public URI getURI() {
+				return (this.uri != null ? this.uri : super.getURI());
+			}
+
+			@Override
+			public String getContextPath() {
+				return super.getContextPath();
+			}
+
+			@Override
+			public HttpHeaders getHeaders() {
+				return super.getHeaders();
+			}
+		}
+
+	}
+}

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

@@ -45,6 +45,7 @@ public class GatewayIntegrationTests {
 
 	private static final String HANDLER_MAPPER_HEADER = "X-Gateway-Handler-Mapper-Class";
 	private static final String ROUTE_ID_HEADER = "X-Gateway-Route-Id";
+	public static final Duration DURATION = Duration.ofSeconds(3);
 
 	@LocalServerPort
 	private int port;
@@ -100,7 +101,37 @@ public class GatewayIntegrationTests {
 									assertThat(headers).containsEntry("X-Request-Foo", "Bar");
 								})
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
+		);
+	}
+
+	@Test
+	public void addRequestParameterFilterWorksBlankQuery() {
+		testRequestParameterFilter("");
+	}
+
+	@Test
+	public void addRequestParameterFilterWorksNonBlankQuery() {
+		testRequestParameterFilter("?baz=bam");
+	}
+
+	private void testRequestParameterFilter(String query) {
+		Mono<Map> result = webClient.exchange(
+				GET("http://localhost:" + port + "/get" + query)
+						.header("Host", "www.addrequestparameter.org")
+						.build()
+		).then(response -> response.body(toMono(Map.class)));
+
+		verify( () ->
+				StepVerifier.create(result)
+						.consumeNextWith(
+								response -> {
+									assertThat(response).containsKey("args").isInstanceOf(Map.class);
+									Map<String, Object> args = (Map<String, Object>) response.get("args");
+									assertThat(args).containsEntry("foo", "bar");
+								})
+						.expectComplete()
+						.verify(DURATION)
 		);
 	}
 
@@ -121,7 +152,7 @@ public class GatewayIntegrationTests {
 											.isEqualTo("Bar");
 								})
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
 		);
 	}
 
@@ -175,7 +206,7 @@ public class GatewayIntegrationTests {
 									assertThat(statusCode).isEqualTo(HttpStatus.OK);
 								})
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
 		);
 	}
 
@@ -192,7 +223,7 @@ public class GatewayIntegrationTests {
 				StepVerifier.create(result)
 						.consumeNextWith(map -> assertThat(map).containsEntry("data", "testdata"))
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
 		);
 	}
 
@@ -215,7 +246,7 @@ public class GatewayIntegrationTests {
 									assertThat(headers).doesNotContainKey("X-Request-Foo");
 								})
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
 		);
 	}
 
@@ -235,7 +266,7 @@ public class GatewayIntegrationTests {
 									assertThat(httpHeaders).doesNotContainKey("X-Request-Foo");
 								})
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
 		);
 	}
 
@@ -255,7 +286,7 @@ public class GatewayIntegrationTests {
 									assertThat(statusCode).isEqualTo(HttpStatus.OK);
 								})
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
 		);
 	}
 
@@ -275,7 +306,7 @@ public class GatewayIntegrationTests {
 									assertThat(statusCode).isEqualTo(HttpStatus.OK);
 								})
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
 		);
 	}
 
@@ -296,7 +327,7 @@ public class GatewayIntegrationTests {
 									assertThat(httpHeaders.get("X-Request-Foo")).containsExactly("Bar");
 								})
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
 		);
 	}
 
@@ -325,7 +356,7 @@ public class GatewayIntegrationTests {
 									assertThat(statusCode).isEqualTo(status);
 								})
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
 		);
 	}
 
@@ -348,7 +379,7 @@ public class GatewayIntegrationTests {
 									assertThat(statusCode).isEqualTo(HttpStatus.OK);
 								})
 						.expectComplete()
-						.verify(Duration.ofSeconds(3))
+						.verify(DURATION)
 		);
 	}
 

src/test/resources/application.yml

@@ -29,6 +29,15 @@ spring:
         filters:
         - AddRequestHeader=X-Request-Foo, Bar
 
+      # =====================================
+      - id: add_request_parameter_test
+        uri: http://httpbin.org:80
+        predicates:
+        - Host=**.addrequestparameter.org
+        - Url=/get
+        filters:
+        - AddRequestParameter=foo, bar
+
       # =====================================
       - id: add_response_header_test
         uri: http://httpbin.org:80