Support epoch millisecond values for datetime predicates in WebMVC

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

@@ -11,6 +11,7 @@ You can combine multiple route predicate factories with the `RequestPredicate.an
 
 The `After` route predicate factory takes one parameter, a `datetime` (which is a java `ZonedDateTime`).
 This predicate matches requests that happen after the specified datetime.
+The datetime can be specified as a ZonedDateTime string or as epoch milliseconds.
 The following example configures an after route predicate:
 
 .application.yml
@@ -27,6 +28,22 @@ spring:
           - After=2017-01-20T17:42:47.789-07:00[America/Denver]
 ----
 
+The datetime can also be specified as epoch milliseconds:
+
+.application.yml
+[source,yaml]
+----
+spring:
+  cloud:
+    gateway:
+      mvc:
+        routes:
+        - id: after_route
+          uri: https://example.org
+          predicates:
+          - After=1484968967789
+----
+
 .GatewaySampleApplication.java
 [source,java]
 ----
@@ -56,6 +73,7 @@ This route matches any request made after Jan 20, 2017 17:42 Mountain Time (Denv
 
 The `Before` route predicate factory takes one parameter, a `datetime` (which is a java `ZonedDateTime`).
 This predicate matches requests that happen before the specified `datetime`.
+The datetime can be specified as a ZonedDateTime string or as epoch milliseconds.
 The following example configures a before route predicate:
 
 .application.yml
@@ -72,6 +90,22 @@ spring:
           - Before=2017-01-20T17:42:47.789-07:00[America/Denver]
 ----
 
+The datetime can also be specified as epoch milliseconds:
+
+.application.yml
+[source,yaml]
+----
+spring:
+  cloud:
+    gateway:
+      mvc:
+        routes:
+        - id: before_route
+          uri: https://example.org
+          predicates:
+          - Before=1484968967789
+----
+
 .GatewaySampleApplication.java
 [source,java]
 ----
@@ -103,6 +137,7 @@ The `Between` route predicate factory takes two parameters, `datetime1` and `dat
 which are java `ZonedDateTime` objects.
 This predicate matches requests that happen after `datetime1` and before `datetime2`.
 The `datetime2` parameter must be after `datetime1`.
+The datetimes can be specified as ZonedDateTime strings or as epoch milliseconds.
 The following example configures a between route predicate:
 
 .application.yml
@@ -119,6 +154,22 @@ spring:
           - Between=2017-01-20T17:42:47.789-07:00[America/Denver], 2017-01-21T17:42:47.789-07:00[America/Denver]
 ----
 
+The datetimes can also be specified as epoch milliseconds:
+
+.application.yml
+[source,yaml]
+----
+spring:
+  cloud:
+    gateway:
+      mvc:
+        routes:
+        - id: between_route
+          uri: https://example.org
+          predicates:
+          - Between=1484968967789, 1485055367789
+----
+
 .GatewaySampleApplication.java
 [source,java]
 ----

spring-cloud-gateway-server-webmvc/src/main/java/org/springframework/cloud/gateway/server/mvc/config/RouterFunctionHolderFactory.java

@@ -60,7 +60,9 @@
 import org.springframework.cloud.gateway.server.mvc.invoke.reflect.ReflectiveOperationInvoker;
 import org.springframework.cloud.gateway.server.mvc.predicate.PredicateBeanFactoryDiscoverer;
 import org.springframework.cloud.gateway.server.mvc.predicate.PredicateDiscoverer;
+import org.springframework.cloud.gateway.server.mvc.support.StringToZonedDateTimeConverter;
 import org.springframework.core.convert.ConversionService;
+import org.springframework.core.convert.support.ConfigurableConversionService;
 import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.core.env.Environment;
 import org.springframework.core.log.LogMessage;
@@ -82,6 +84,7 @@
  *
  * @author Spencer Gibb
  * @author Jürgen Wißkirchen
+ * @author raccoonback
  */
 public class RouterFunctionHolderFactory {
 
@@ -112,7 +115,7 @@ public String toString() {
 
 	private final PredicateDiscoverer predicateDiscoverer = new PredicateDiscoverer();
 
-	private final ParameterValueMapper parameterValueMapper = new ConversionServiceParameterValueMapper();
+	private final ParameterValueMapper parameterValueMapper;
 
 	private final BeanFactory beanFactory;
 
@@ -140,6 +143,12 @@ public RouterFunctionHolderFactory(Environment env, BeanFactory beanFactory,
 		else {
 			this.conversionService = DefaultConversionService.getSharedInstance();
 		}
+
+		if (this.conversionService instanceof ConfigurableConversionService configurableConversionService) {
+			configurableConversionService.addConverter(new StringToZonedDateTimeConverter());
+		}
+
+		this.parameterValueMapper = new ConversionServiceParameterValueMapper(this.conversionService);
 	}
 
 	/**

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

@@ -91,7 +91,6 @@ public static RequestPredicate before(ZonedDateTime dateTime) {
 		return request -> ZonedDateTime.now().isBefore(dateTime);
 	}
 
-	// TODO: accept and test datetime predicates (including yaml config)
 	@Shortcut
 	public static RequestPredicate between(ZonedDateTime dateTime1, ZonedDateTime dateTime2) {
 		return request -> {

spring-cloud-gateway-server-webmvc/src/main/java/org/springframework/cloud/gateway/server/mvc/support/StringToZonedDateTimeConverter.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2025-present 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.server.mvc.support;
+
+import java.time.Instant;
+import java.time.ZoneOffset;
+import java.time.ZonedDateTime;
+
+import org.springframework.core.convert.converter.Converter;
+
+/**
+ * Converter for converting String to ZonedDateTime. Supports both ISO-8601 format and
+ * epoch milliseconds.
+ *
+ * @author raccoonback
+ */
+public class StringToZonedDateTimeConverter implements Converter<String, ZonedDateTime> {
+
+	@Override
+	public ZonedDateTime convert(String source) {
+		try {
+			long epoch = Long.parseLong(source);
+			return Instant.ofEpochMilli(epoch).atOffset(ZoneOffset.ofTotalSeconds(0)).toZonedDateTime();
+		}
+		catch (NumberFormatException e) {
+			// try ZonedDateTime instead
+			return ZonedDateTime.parse(source);
+		}
+	}
+
+}