Add ServerWebExchangeArgumentResolver

Issue: SPR-14658

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerAdapter.java

@@ -217,6 +217,7 @@ public class RequestMappingHandlerAdapter implements HandlerAdapter, BeanFactory
 		// Type-based argument resolution
 		resolvers.add(new HttpEntityArgumentResolver(getMessageReaders(), getValidator(), adapterRegistry));
 		resolvers.add(new ModelArgumentResolver());
+		resolvers.add(new ServerWebExchangeArgumentResolver());
 
 		// Custom resolvers
 		if (getCustomArgumentResolvers() != null) {

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/annotation/ServerWebExchangeArgumentResolver.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2002-2016 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
+ *
+ *      http://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.reactive.result.method.annotation;
+
+import reactor.core.publisher.Mono;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.ui.ModelMap;
+import org.springframework.web.reactive.result.method.HandlerMethodArgumentResolver;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.WebSession;
+
+/**
+ * Resolves ServerWebExchange-related method argument values of the following types:
+ * <ul>
+ * <li>{@link ServerWebExchange}
+ * <li>{@link ServerHttpRequest}
+ * <li>{@link WebSession}
+ * <li>{@link HttpMethod}
+ * <li>{@link ServerHttpResponse}
+ * </ul>
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public class ServerWebExchangeArgumentResolver implements HandlerMethodArgumentResolver {
+
+	@Override
+	public boolean supportsParameter(MethodParameter parameter) {
+		Class<?> paramType = parameter.getParameterType();
+		return (ServerWebExchange.class.isAssignableFrom(paramType) ||
+				ServerHttpRequest.class.isAssignableFrom(paramType) ||
+				ServerHttpResponse.class.isAssignableFrom(paramType) ||
+				WebSession.class.isAssignableFrom(paramType) ||
+				HttpMethod.class == paramType);
+	}
+
+	@Override
+	public Mono<Object> resolveArgument(MethodParameter parameter, ModelMap model, ServerWebExchange exchange) {
+		Class<?> paramType = parameter.getParameterType();
+		if (ServerWebExchange.class.isAssignableFrom(paramType)) {
+			return Mono.just(exchange);
+		}
+		else if (ServerHttpRequest.class.isAssignableFrom(paramType)) {
+			return Mono.just(exchange.getRequest());
+		}
+		else if (ServerHttpResponse.class.isAssignableFrom(paramType)) {
+			return Mono.just(exchange.getResponse());
+		}
+		else if (WebSession.class.isAssignableFrom(paramType)) {
+			return exchange.getSession().cast(Object.class);
+		}
+		else if (HttpMethod.class == paramType) {
+			return Mono.just(exchange.getRequest().getMethod());
+		}
+		else {
+			// should never happen...
+			return Mono.error(new UnsupportedOperationException(
+					"Unknown parameter type: " + paramType + " in method: " + parameter.getMethod()));
+		}
+	}
+
+}

spring-web-reactive/src/test/java/org/springframework/web/reactive/result/method/annotation/ServerWebExchangeArgumentResolverTests.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2002-2016 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
+ *
+ *      http://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.reactive.result.method.annotation;
+
+import java.net.URI;
+
+import org.junit.Before;
+import org.junit.Test;
+import reactor.core.publisher.Mono;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.server.reactive.MockServerHttpRequest;
+import org.springframework.http.server.reactive.MockServerHttpResponse;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.ui.ModelMap;
+import org.springframework.web.reactive.result.ResolvableMethod;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.WebSession;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static junit.framework.TestCase.assertFalse;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Unit tests for {@link ServerWebExchangeArgumentResolver}.
+ * @author Rossen Stoyanchev
+ */
+public class ServerWebExchangeArgumentResolverTests {
+
+	private ServerWebExchangeArgumentResolver resolver = new ServerWebExchangeArgumentResolver();
+
+	private ServerWebExchange exchange;
+
+	private ResolvableMethod testMethod = ResolvableMethod.onClass(getClass()).name("handle");
+
+
+	@Before
+	public void setUp() throws Exception {
+		ServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, new URI("/path"));
+		ServerHttpResponse response = new MockServerHttpResponse();
+
+		WebSession session = mock(WebSession.class);
+		WebSessionManager sessionManager = mock(WebSessionManager.class);
+		when(sessionManager.getSession(any())).thenReturn(Mono.just(session));
+
+		this.exchange = new DefaultServerWebExchange(request, response, sessionManager);
+	}
+
+	@Test
+	public void supportsParameter() throws Exception {
+		assertTrue(this.resolver.supportsParameter(parameter(ServerWebExchange.class)));
+		assertTrue(this.resolver.supportsParameter(parameter(ServerHttpRequest.class)));
+		assertTrue(this.resolver.supportsParameter(parameter(ServerHttpResponse.class)));
+		assertTrue(this.resolver.supportsParameter(parameter(WebSession.class)));
+		assertTrue(this.resolver.supportsParameter(parameter(HttpMethod.class)));
+		assertFalse(this.resolver.supportsParameter(parameter(String.class)));
+	}
+
+	@Test
+	public void resolveArgument() throws Exception {
+		testResolveArgument(parameter(ServerWebExchange.class), this.exchange);
+		testResolveArgument(parameter(ServerHttpRequest.class), this.exchange.getRequest());
+		testResolveArgument(parameter(ServerHttpResponse.class), this.exchange.getResponse());
+		testResolveArgument(parameter(WebSession.class), this.exchange.getSession().block());
+		testResolveArgument(parameter(HttpMethod.class), HttpMethod.GET);
+	}
+
+	private void testResolveArgument(MethodParameter parameter, Object expected) {
+		Mono<Object> mono = this.resolver.resolveArgument(parameter, new ModelMap(), this.exchange);
+		assertSame(expected, mono.block());
+	}
+
+	private MethodParameter parameter(Class<?> parameterType) {
+		return this.testMethod.resolveParam(parameter -> parameterType.equals(parameter.getParameterType()));
+	}
+
+
+	@SuppressWarnings("unused")
+	public void handle(
+			ServerWebExchange exchange,
+			ServerHttpRequest request,
+			ServerHttpResponse response,
+			WebSession session,
+			HttpMethod httpMethod,
+			String s) {
+	}
+
+}