Add UrlHandlerFilter for WebFlux

Closes gh-32830

spring-web/src/test/java/org/springframework/web/filter/reactive/UrlHandlerFilterTests.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright 2002-2024 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.web.filter.reactive;
+
+import java.net.URI;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
+import reactor.core.publisher.Mono;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.WebFilterChain;
+import org.springframework.web.server.WebHandler;
+import org.springframework.web.server.handler.DefaultWebFilterChain;
+import org.springframework.web.testfixture.http.server.reactive.MockServerHttpRequest;
+import org.springframework.web.testfixture.server.MockServerWebExchange;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Unit tests for {@link UrlHandlerFilter}.
+ *
+ * @author Rossen Stoyanchev
+ */
+public class UrlHandlerFilterTests {
+
+	@Test
+	void requestMutation() {
+		UrlHandlerFilter filter = UrlHandlerFilter.trailingSlashHandler("/path/**").mutateRequest().build();
+
+		String path = "/path/123";
+		MockServerHttpRequest original = MockServerHttpRequest.get(path + "/").build();
+		ServerWebExchange exchange = MockServerWebExchange.from(original);
+
+		ServerHttpRequest actual = invokeFilter(filter, exchange);
+
+		assertThat(actual).isNotNull().isNotSameAs(original);
+		assertThat(actual.getPath().value()).isEqualTo(path);
+	}
+
+	@Test
+	void redirect() {
+		HttpStatus status = HttpStatus.PERMANENT_REDIRECT;
+		UrlHandlerFilter filter = UrlHandlerFilter.trailingSlashHandler("/path/*").redirect(status).build();
+
+		String path = "/path/123";
+		MockServerHttpRequest original = MockServerHttpRequest.get(path + "/").build();
+		ServerWebExchange exchange = MockServerWebExchange.from(original);
+
+		assertThatThrownBy(() -> invokeFilter(filter, exchange))
+				.hasMessageContaining("No argument value was captured");
+
+		assertThat(exchange.getResponse().getStatusCode()).isEqualTo(status);
+		assertThat(exchange.getResponse().getHeaders().getLocation()).isEqualTo(URI.create(path));
+	}
+
+	@Test
+	void noUrlHandling() {
+		testNoUrlHandling("/path/**", "/path/123");
+		testNoUrlHandling("/path/*", "/path/123");
+		testNoUrlHandling("/**", "/"); // gh-33444
+	}
+
+	private static void testNoUrlHandling(String pattern, String path) {
+
+		// No request mutation
+		UrlHandlerFilter filter = UrlHandlerFilter.trailingSlashHandler(pattern).mutateRequest().build();
+
+		MockServerHttpRequest request = MockServerHttpRequest.get(path).build();
+		ServerWebExchange exchange = MockServerWebExchange.from(request);
+
+		ServerHttpRequest actual = invokeFilter(filter, exchange);
+
+		assertThat(actual).isNotNull().isSameAs(request);
+		assertThat(actual.getPath().value()).isEqualTo(path);
+
+		// No redirect
+		HttpStatus status = HttpStatus.PERMANENT_REDIRECT;
+		filter = UrlHandlerFilter.trailingSlashHandler(pattern).redirect(status).build();
+
+		request = MockServerHttpRequest.get(path).build();
+		exchange = MockServerWebExchange.from(request);
+
+		actual = invokeFilter(filter, exchange);
+
+		assertThat(actual).isNotNull().isSameAs(request);
+		assertThat(exchange.getResponse().getStatusCode()).isNull();
+		assertThat(exchange.getResponse().getHeaders().getLocation()).isNull();
+	}
+
+	private static ServerHttpRequest invokeFilter(UrlHandlerFilter filter, ServerWebExchange exchange) {
+		WebHandler handler = mock(WebHandler.class);
+		ArgumentCaptor<ServerWebExchange> captor = ArgumentCaptor.forClass(ServerWebExchange.class);
+		given(handler.handle(captor.capture())).willReturn(Mono.empty());
+
+		WebFilterChain chain = new DefaultWebFilterChain(handler, List.of(filter));
+		filter.filter(exchange, chain).block();
+
+		return captor.getValue().getRequest();
+	}
+
+}