Adds GatewayRequestPredicates.query()

docs/modules/ROOT/pages/spring-cloud-gateway-server-mvc/gateway-request-predicates.adoc

@@ -390,8 +390,6 @@ Map<String, Object> uriVariables = MvcUtils.getUriTemplateVariables(request);
 String segment = uriVariables.get("segment");
 ----
 
-////
-TODO: query predicate
 [[query-request-predicate]]
 == The Query Request Predicate
 
@@ -411,6 +409,26 @@ spring:
         - Query=green
 ----
 
+.GatewaySampleApplication.java
+[source,java]
+----
+import org.springframework.http.HttpMethod;
+import static org.springframework.cloud.gateway.server.mvc.handler.GatewayRouterFunctions.route;
+import static org.springframework.cloud.gateway.server.mvc.handler.HandlerFunctions.http;
+import static org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates.query;
+
+@Configuration
+class RouteConfiguration {
+
+    @Bean
+    public RouterFunction<ServerResponse> gatewayRouterFunctionsQuery() {
+		return route("query_route")
+			.route(query("green"), http("https://example.org"))
+			.build();
+    }
+}
+----
+
 The preceding route matches if the request contained a `green` query parameter.
 
 .application.yml
@@ -426,8 +444,29 @@ spring:
         - Query=red, gree.
 ----
 
+.GatewaySampleApplication.java
+[source,java]
+----
+import org.springframework.http.HttpMethod;
+import static org.springframework.cloud.gateway.server.mvc.handler.GatewayRouterFunctions.route;
+import static org.springframework.cloud.gateway.server.mvc.handler.HandlerFunctions.http;
+import static org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates.query;
+
+@Configuration
+class RouteConfiguration {
+
+    @Bean
+    public RouterFunction<ServerResponse> gatewayRouterFunctionsQuery() {
+		return route("query_route")
+			.route(query("red", "gree."), http("https://example.org"))
+			.build();
+    }
+}
+----
+
 The preceding route matches if the request contained a `red` query parameter whose value matched the `gree.` regexp, so `green` and `greet` would match.
 
+////
 TODO: remoteAddr predicate
 [[remoteaddr-request-predicate]]
 == The RemoteAddr Request Predicate
@@ -511,7 +550,7 @@ RemoteAddressResolver resolver = XForwardedRemoteAddressResolver
 [[weight-request-predicate]]
 == The Weight Request Predicate
 
-The `Weight` route predicate factory takes two arguments: `group` and `weight` (an int). The weights are calculated per group.
+The `Weight` route predicate factory takes two arguments: `group` and `weight` (an `int`). The weights are calculated per group.
 The following example configures a weight route predicate:
 
 .application.yml
@@ -554,7 +593,7 @@ class RouteConfiguration {
 }
 ----
 
-This route would forward ~80% of traffic to https://weighthigh.org and ~20% of traffic to https://weightlow.org
+This route would forward ~80% of traffic to https://weighthigh.org and ~20% of traffic to https://weightlow.org.
 
 ////
 TODO: XForwardedRemoteAddr predicate

spring-cloud-gateway-server-mvc/src/main/java/org/springframework/cloud/gateway/server/mvc/handler/ProxyExchangeHandlerFunction.java

@@ -69,11 +69,10 @@ public ServerResponse handle(ServerRequest serverRequest) {
 		boolean encoded = containsEncodedQuery(serverRequest.uri());
 		// @formatter:off
 		URI url = UriComponentsBuilder.fromUri(serverRequest.uri())
-				// .uri(routeUri)
 				.scheme(uri.getScheme())
 				.host(uri.getHost())
 				.port(uri.getPort())
-				.queryParams(serverRequest.params())
+				.replaceQueryParams(serverRequest.params())
 				.build(encoded)
 				.toUri();
 		// @formatter:on

spring-cloud-gateway-server-mvc/src/main/java/org/springframework/cloud/gateway/server/mvc/predicate/GatewayRequestPredicates.java

@@ -186,6 +186,32 @@ public static RequestPredicate path(String... patterns) {
 		return requestPredicate;
 	}
 
+	/**
+	 * Return a {@code RequestPredicate} that tests the presence of a request parameter.
+	 * @param param the name of the query parameter
+	 * @return a predicate that tests for the presence of a given param
+	 */
+	@Shortcut
+	public static RequestPredicate query(String param) {
+		return query(param, null);
+	}
+
+	/**
+	 * Return a {@code RequestPredicate} that tests the presence of a request parameter if
+	 * the regexp is empty, or, otherwise finds if any value of the parameter matches the
+	 * regexp.
+	 * @param param the name of the query parameter
+	 * @param regexp an optional regular expression to match.
+	 * @return a predicate that tests for the given param and regexp.
+	 */
+	@Shortcut
+	public static RequestPredicate query(String param, String regexp) {
+		if (!StringUtils.hasText(regexp)) {
+			return request -> request.param(param).isPresent();
+		}
+		return request -> request.param(param).stream().anyMatch(value -> value.matches(regexp));
+	}
+
 	public static <T> RequestPredicate readBody(Class<T> inClass, Predicate<T> predicate) {
 		return new ReadBodyPredicate<>(inClass, predicate);
 	}

spring-cloud-gateway-server-mvc/src/test/java/org/springframework/cloud/gateway/server/mvc/ServerMvcIntegrationTests.java

@@ -119,6 +119,7 @@
 import static org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates.cookie;
 import static org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates.header;
 import static org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates.host;
+import static org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates.query;
 import static org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates.readBody;
 import static org.springframework.cloud.gateway.server.mvc.test.TestUtils.getMap;
 import static org.springframework.http.MediaType.APPLICATION_FORM_URLENCODED;
@@ -605,6 +606,19 @@ public void forwardNon200StatusWorks() {
 				.isEqualTo("hello2");
 	}
 
+	@Test
+	@SuppressWarnings("rawtypes")
+	public void queryParamWorks() {
+		restClient.get().uri("/get?foo=bar").exchange().expectStatus().isOk().expectBody(Map.class)
+				.consumeWith(result -> {
+					Map responseBody = result.getResponseBody();
+					assertThat(responseBody).containsKey("args");
+					Map args = getMap(responseBody, "args");
+					assertThat(args).containsKey("foo");
+					assertThat(args.get("foo")).isEqualTo("bar");
+				});
+	}
+
 	@SpringBootConfiguration
 	@EnableAutoConfiguration
 	@LoadBalancerClient(name = "httpbin", configuration = TestLoadBalancerConfig.Httpbin.class)
@@ -1126,6 +1140,16 @@ public RouterFunction<ServerResponse> gatewayRouterFunctionsForwardNon200Status(
 			// @formatter:on
 		}
 
+		@Bean
+		public RouterFunction<ServerResponse> gatewayRouterFunctionsQuery() {
+			// @formatter:off
+			return route("testqueryparam")
+					.route(query("foo", "bar"), http())
+					.before(new HttpbinUriResolver())
+					.build();
+			// @formatter:on
+		}
+
 		private Predicate<Event> eventPredicate(String foo) {
 			return new Predicate<>() {
 				@Override