return Observable from Spring MVC

spencergibb · Feb 24, 2015 · a301aba · rstoyanchev · May 29, 2015 · a301aba
1 parent e0db270
commit a301aba
Show file tree

Hide file tree

Showing 3 changed files with 42 additions and 20 deletions.
diff --git a/myfeed-core/src/main/java/myfeed/MyfeedAutoConfig.java b/myfeed-core/src/main/java/myfeed/MyfeedAutoConfig.java
@@ -2,6 +2,8 @@
 
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
 import org.springframework.cloud.netflix.ribbon.RibbonInterceptor;
 import org.springframework.context.annotation.Bean;
@@ -14,7 +16,12 @@
 import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
 import org.springframework.web.client.AsyncRestTemplate;
 import org.springframework.web.client.RestTemplate;
+import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
+import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
+import rx.Observable;
 
+import javax.annotation.PostConstruct;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -89,4 +96,28 @@ public AsyncRestTemplate asyncRestTemplate(RibbonInterceptor interceptor, LoadBa
 	public TraversonFactory traversonFactory(LoadBalancerClient loadBalancerClient) {
 		return new TraversonFactory(loadBalancerClient);
 	}
+
+	@Configuration
+	@ConditionalOnClass(Observable.class)
+	public static class WebConfig extends WebMvcConfigurerAdapter {
+		@Autowired
+		private RequestMappingHandlerAdapter requestMappingHandlerAdapter;
+
+		@Bean
+		public ObservableReturnValueHandler observableReturnValueHandler() {
+			return new ObservableReturnValueHandler();
+		}
+
+		@PostConstruct
+		public void init() {
+			final List<HandlerMethodReturnValueHandler> originalHandlers = new ArrayList<>(requestMappingHandlerAdapter.getReturnValueHandlers());
+			originalHandlers.add(0, observableReturnValueHandler());
+			requestMappingHandlerAdapter.setReturnValueHandlers(originalHandlers);
+		}
+
+		/*@Override
+		public void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> returnValueHandlers) {
+			returnValueHandlers.add(0, observableReturnValueHandler());
+		}*/
+	}
 }
diff --git a/myfeed-core/src/main/java/myfeed/ObservableReturnValueHandler.java b/myfeed-core/src/main/java/myfeed/ObservableReturnValueHandler.java
@@ -2,11 +2,11 @@
 
 import org.springframework.core.MethodParameter;
 import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.context.request.async.WebAsyncUtils;
 import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
 import org.springframework.web.method.support.ModelAndViewContainer;
-import rx.Observable;
 
-import java.util.Map;
+import rx.Observable;
 
 /**
  * @author Spencer Gibb
@@ -23,13 +23,10 @@ public void handleReturnValue(Object returnValue, MethodParameter returnType, Mo
 			return;
 		}
 
-		if (returnValue instanceof Observable) {
-			Observable observable = (Observable) returnValue;
-			mavContainer.addAttribute(observable.toBlocking().first());
-		} else {
-			// should not happen
-			throw new UnsupportedOperationException("Unexpected return type: " +
-					returnType.getParameterType().getName() + " in method: " + returnType.getMethod());
-		}
+		Observable<?> observable = Observable.class.cast(returnValue);
+
+		ObservableAdapter<?> adapter = new ObservableAdapter<>(observable);
+		WebAsyncUtils.getAsyncManager(webRequest)
+				.startDeferredResultProcessing(adapter, mavContainer);
 	}
 }
diff --git a/myfeed-ui/src/main/java/myfeed/ui/UiController.java b/myfeed-ui/src/main/java/myfeed/ui/UiController.java
@@ -1,14 +1,14 @@
 package myfeed.ui;
 
+import static rx.Observable.*;
+
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
 
 import lombok.Data;
 import lombok.NoArgsConstructor;
 import myfeed.AsyncRest;
-import myfeed.ObservableAdapter;
-import myfeed.Rest;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.core.ParameterizedTypeReference;
@@ -18,11 +18,8 @@
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
-import org.springframework.web.context.request.async.DeferredResult;
 import rx.Observable;
 
-import static rx.Observable.*;
-
 /**
  * @author Spencer Gibb
  */
@@ -34,11 +31,8 @@ public class UiController {
 	@Autowired
 	private AsyncRest rest;
 
-	@Autowired
-	private Rest syncRest;
-
 	@RequestMapping("/ui/feed/{username}")
-	public DeferredResult<Feed> feed(@PathVariable("username") String username) {
+	public Observable<Feed> feed(@PathVariable("username") String username) {
 		Observable<List<FeedItem>> feedItems = from(rest.get("http://myfeed-feed/{username}", FEED_ITEM_TYPE, username))
 				.map(HttpEntity::getBody);
 
@@ -56,7 +50,7 @@ public DeferredResult<Feed> feed(@PathVariable("username") String username) {
 					return zip(u, following, feedItems, Feed::new);
 				});
 
-		return new ObservableAdapter<>(feed);
+		return feed;
 	}
 
 	private Observable<ResponseEntity<User>> getUser(String url, String username) {