Query param route predicate - extension of QueryRoutePredicateFactory

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/config/GatewayAutoConfiguration.java

@@ -137,6 +137,7 @@
 import org.springframework.cloud.gateway.handler.predicate.MethodRoutePredicateFactory;
 import org.springframework.cloud.gateway.handler.predicate.PathRoutePredicateFactory;
 import org.springframework.cloud.gateway.handler.predicate.PredicateDefinition;
+import org.springframework.cloud.gateway.handler.predicate.QueryParamRoutePredicateFactory;
 import org.springframework.cloud.gateway.handler.predicate.QueryRoutePredicateFactory;
 import org.springframework.cloud.gateway.handler.predicate.ReadBodyRoutePredicateFactory;
 import org.springframework.cloud.gateway.handler.predicate.RemoteAddrRoutePredicateFactory;
@@ -206,6 +207,7 @@ public StringToZonedDateTimeConverter stringToZonedDateTimeConverter() {
 	 * @deprecated in favour of
 	 * {@link org.springframework.cloud.gateway.support.config.KeyValueConverter}
 	 */
+	@Deprecated
 	@Bean
 	public org.springframework.cloud.gateway.support.KeyValueConverter deprecatedKeyValueConverter() {
 		return new org.springframework.cloud.gateway.support.KeyValueConverter();
@@ -470,6 +472,12 @@ public PathRoutePredicateFactory pathRoutePredicateFactory() {
 		return new PathRoutePredicateFactory();
 	}
 
+	@Bean
+	@ConditionalOnEnabledPredicate
+	public QueryParamRoutePredicateFactory queryParamRoutePredicateFactory() {
+		return new QueryParamRoutePredicateFactory();
+	}
+
 	@Bean
 	@ConditionalOnEnabledPredicate
 	public QueryRoutePredicateFactory queryRoutePredicateFactory() {

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/handler/predicate/QueryParamRoutePredicateFactory.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2013-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.gateway.handler.predicate;
+
+import java.util.List;
+import java.util.function.Predicate;
+
+import jakarta.validation.constraints.NotEmpty;
+import jakarta.validation.constraints.NotNull;
+
+import org.springframework.validation.annotation.Validated;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A predicate that checks if a query parameter value matches criteria of a given
+ * predicate.
+ *
+ * @author Francesco Poli
+ */
+public class QueryParamRoutePredicateFactory
+		extends AbstractRoutePredicateFactory<QueryParamRoutePredicateFactory.Config> {
+
+	public QueryParamRoutePredicateFactory() {
+		super(Config.class);
+	}
+
+	@Override
+	public Predicate<ServerWebExchange> apply(Config config) {
+		return new GatewayPredicate() {
+
+			@Override
+			public boolean test(ServerWebExchange exchange) {
+				List<String> values = exchange.getRequest().getQueryParams().get(config.param);
+				if (values == null) {
+					return false;
+				}
+				for (String value : values) {
+					if (value != null && config.predicate.test(value)) {
+						return true;
+					}
+				}
+				return false;
+			}
+
+			@Override
+			public Object getConfig() {
+				return config;
+			}
+
+			@Override
+			public String toString() {
+				return String.format("QueryParam: param=%s", config.param);
+			}
+		};
+	}
+
+	/**
+	 * {@link QueryParamRoutePredicateFactory} configuration class.
+	 *
+	 * @author Francesco Poli
+	 */
+	@Validated
+	public static class Config {
+
+		@NotEmpty
+		private String param;
+
+		@NotNull
+		private Predicate<String> predicate;
+
+		public Config setParam(String param) {
+			this.param = param;
+			return this;
+		}
+
+		public Config setPredicate(Predicate<String> predicate) {
+			this.predicate = predicate;
+			return this;
+		}
+
+	}
+
+}

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/handler/predicate/QueryRoutePredicateFactory.java

@@ -19,9 +19,8 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.function.Predicate;
-
+import jakarta.validation.constraints.AssertTrue;
 import jakarta.validation.constraints.NotEmpty;
-
 import org.springframework.util.StringUtils;
 import org.springframework.validation.annotation.Validated;
 import org.springframework.web.server.ServerWebExchange;
@@ -41,21 +40,26 @@ public class QueryRoutePredicateFactory extends AbstractRoutePredicateFactory<Qu
 	 */
 	public static final String REGEXP_KEY = "regexp";
 
+	/**
+	 * Predicate key.
+	 */
+	public static final String PREDICATE_KEY = "predicate";
+
 	public QueryRoutePredicateFactory() {
 		super(Config.class);
 	}
 
 	@Override
 	public List<String> shortcutFieldOrder() {
-		return Arrays.asList(PARAM_KEY, REGEXP_KEY);
+		return Arrays.asList(PARAM_KEY, REGEXP_KEY, PREDICATE_KEY);
 	}
 
 	@Override
 	public Predicate<ServerWebExchange> apply(Config config) {
 		return new GatewayPredicate() {
 			@Override
 			public boolean test(ServerWebExchange exchange) {
-				if (!StringUtils.hasText(config.regexp)) {
+				if (!StringUtils.hasText(config.regexp) && config.predicate == null) {
 					// check existence of header
 					return exchange.getRequest().getQueryParams().containsKey(config.param);
 				}
@@ -64,8 +68,13 @@ public boolean test(ServerWebExchange exchange) {
 				if (values == null) {
 					return false;
 				}
+
+				Predicate<String> predicate = config.predicate;
+				if (StringUtils.hasText(config.regexp)) {
+					predicate = value -> value.matches(config.regexp);
+				}
 				for (String value : values) {
-					if (value != null && value.matches(config.regexp)) {
+					if (value != null && predicate.test(value)) {
 						return true;
 					}
 				}
@@ -92,6 +101,8 @@ public static class Config {
 
 		private String regexp;
 
+		private Predicate<String> predicate;
+
 		public String getParam() {
 			return param;
 		}
@@ -110,6 +121,26 @@ public Config setRegexp(String regexp) {
 			return this;
 		}
 
+		public Predicate<String> getPredicate() {
+			return predicate;
+		}
+
+		public Config setPredicate(Predicate<String> predicate) {
+			this.predicate = predicate;
+			return this;
+		}
+
+		/**
+		 * Enforces the validation done on predicate configuration: {@link #regexp} and
+		 * {@link #predicate} can't be both set at runtime.
+		 * @return <code>false</code> if {@link #regexp} and {@link #predicate} are both
+		 * set in this predicate factory configuration
+		 */
+		@AssertTrue
+		public boolean isValid() {
+			return !(StringUtils.hasText(regexp) && predicate != null);
+		}
+
 	}
 
 }

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/route/builder/PredicateSpec.java

@@ -31,6 +31,7 @@
 import org.springframework.cloud.gateway.handler.predicate.HostRoutePredicateFactory;
 import org.springframework.cloud.gateway.handler.predicate.MethodRoutePredicateFactory;
 import org.springframework.cloud.gateway.handler.predicate.PathRoutePredicateFactory;
+import org.springframework.cloud.gateway.handler.predicate.QueryParamRoutePredicateFactory;
 import org.springframework.cloud.gateway.handler.predicate.QueryRoutePredicateFactory;
 import org.springframework.cloud.gateway.handler.predicate.ReadBodyRoutePredicateFactory;
 import org.springframework.cloud.gateway.handler.predicate.RemoteAddrRoutePredicateFactory;
@@ -204,6 +205,18 @@ public <T> BooleanSpec readBody(Class<T> inClass, Predicate<T> predicate) {
 				getBean(ReadBodyRoutePredicateFactory.class).applyAsync(c -> c.setPredicate(inClass, predicate)));
 	}
 
+	/**
+	 * A predicate that checks if a query parameter value matches criteria of a given
+	 * predicate.
+	 * @param param the query parameter name
+	 * @param predicate a predicate to check the value of the param
+	 * @return a {@link BooleanSpec} to be used to add logical operators
+	 */
+	public BooleanSpec queryParam(String param, Predicate<String> predicate) {
+		return asyncPredicate(getBean(QueryParamRoutePredicateFactory.class)
+			.applyAsync(c -> c.setParam(param).setPredicate(predicate)));
+	}
+
 	/**
 	 * A predicate that checks if a query parameter matches a regular expression.
 	 * @param param the query parameter name

spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/handler/predicate/QueryParamRoutePredicateFactoryTests.java

@@ -0,0 +1,146 @@
+/*
+ * Copyright 2013-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.gateway.handler.predicate;
+
+import java.util.function.Predicate;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.system.CapturedOutput;
+import org.springframework.boot.test.system.OutputCaptureExtension;
+import org.springframework.cloud.gateway.handler.predicate.QueryParamRoutePredicateFactory.Config;
+import org.springframework.cloud.gateway.route.RouteLocator;
+import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
+import org.springframework.cloud.gateway.support.HasConfig;
+import org.springframework.cloud.gateway.test.BaseWebClientTests;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Import;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.web.server.ServerWebExchange;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;
+
+/**
+ * Test class for {@link QueryParamRoutePredicateFactory}.
+ *
+ * @see QueryParamRoutePredicateFactory
+ * @author Francesco Poli
+ */
+@SpringBootTest(webEnvironment = RANDOM_PORT)
+@DirtiesContext
+@ExtendWith(OutputCaptureExtension.class)
+public class QueryParamRoutePredicateFactoryTests extends BaseWebClientTests {
+
+	@Test
+	public void noQueryParamWorks(CapturedOutput output) {
+		this.testClient.get()
+			.uri("/get")
+			.exchange()
+			.expectStatus()
+			.isOk()
+			.expectHeader()
+			.valueEquals(ROUTE_ID_HEADER, "default_path_to_httpbin");
+		assertThat(output).doesNotContain("Error applying predicate for route: foo_query_param");
+	}
+
+	@Test
+	public void queryParamPredicateTrue() {
+		this.testClient.get()
+			.uri("/get?foo=1234567")
+			.exchange()
+			.expectStatus()
+			.isOk()
+			.expectHeader()
+			.valueEquals(ROUTE_ID_HEADER, "foo_query_param");
+	}
+
+	@Test
+	public void queryParamPredicateFalse(CapturedOutput output) {
+		this.testClient.get()
+			.uri("/get?foo=123")
+			.exchange()
+			.expectStatus()
+			.isOk()
+			.expectHeader()
+			.valueEquals(ROUTE_ID_HEADER, "default_path_to_httpbin");
+		assertThat(output).doesNotContain("Error applying predicate for route: foo_query_param");
+	}
+
+	@Test
+	public void emptyQueryParamWorks(CapturedOutput output) {
+		this.testClient.get()
+			.uri("/get?foo")
+			.exchange()
+			.expectStatus()
+			.isOk()
+			.expectHeader()
+			.valueEquals(ROUTE_ID_HEADER, "default_path_to_httpbin");
+		assertThat(output).doesNotContain("Error applying predicate for route: foo_query_param");
+	}
+
+	@Test
+	public void testConfig() {
+		Config config = new Config();
+		config.setParam("query_param");
+		Predicate<ServerWebExchange> predicate = new QueryParamRoutePredicateFactory().apply(config);
+		assertTrue(predicate instanceof HasConfig, "Incongruent types for predicate");
+		assertSame(config, ((HasConfig) predicate).getConfig(), "Incongruent config");
+	}
+
+	@Test
+	public void toStringFormat() {
+		Config config = new Config();
+		config.setParam("query_param");
+		Predicate<ServerWebExchange> predicate = new QueryParamRoutePredicateFactory().apply(config);
+		assertThat(predicate.toString()).contains("QueryParam: param=query_param");
+	}
+
+	@EnableAutoConfiguration
+	@SpringBootConfiguration
+	@Import(DefaultTestConfig.class)
+	public static class TestConfig {
+
+		private static final int PARAM_LENGTH = 5;
+
+		@Value("${test.uri}")
+		private String uri;
+
+		@Bean
+		RouteLocator queryParamRouteLocator(RouteLocatorBuilder builder) {
+			return builder.routes()
+				.route("foo_query_param",
+						r -> r.queryParam("foo", queryParamPredicate())
+							.filters(f -> f.prefixPath("/httpbin"))
+							.uri(this.uri))
+				.build();
+		}
+
+		private Predicate<String> queryParamPredicate() {
+			return p -> p == null ? false : p.length() > PARAM_LENGTH;
+		}
+
+	}
+
+}

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

@@ -45,6 +45,7 @@
 		org.springframework.cloud.gateway.handler.predicate.CookieRoutePredicateFactoryTests.class,
 		org.springframework.cloud.gateway.handler.predicate.MethodRoutePredicateFactoryTests.class,
 		org.springframework.cloud.gateway.handler.predicate.BetweenRoutePredicateFactoryTests.class,
+		org.springframework.cloud.gateway.handler.predicate.QueryParamRoutePredicateFactoryTests.class,
 		org.springframework.cloud.gateway.handler.predicate.QueryRoutePredicateFactoryTests.class,
 		org.springframework.cloud.gateway.handler.predicate.WeightRoutePredicateFactoryIntegrationTests.class,
 		org.springframework.cloud.gateway.handler.predicate.HeaderRoutePredicateFactoryTests.class,