add support for ribbon http client in RestTemplate.

fixes gh-280

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/ribbon/RibbonAutoConfiguration.java

@@ -24,6 +24,7 @@
 import org.springframework.boot.autoconfigure.AutoConfigureBefore;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.cloud.client.loadbalancer.LoadBalanced;
 import org.springframework.cloud.client.loadbalancer.LoadBalancerAutoConfiguration;
 import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
 import org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration;
@@ -33,6 +34,8 @@
 
 import com.netflix.client.IClient;
 
+import javax.annotation.PostConstruct;
+
 /**
  * Auto configuration for Ribbon (client side load balancing).
  *
@@ -49,6 +52,22 @@ public class RibbonAutoConfiguration {
 	@Autowired(required = false)
 	private List<RibbonClientSpecification> configurations = new ArrayList<>();
 
+    @Autowired(required = false)
+    @LoadBalanced
+    private RestTemplate restTemplate;
+
+    @PostConstruct
+    public void init() {
+        if (restTemplate != null) {
+            restTemplate.setRequestFactory(ribbonClientHttpRequestFactory());
+        }
+    }
+
+    @Bean
+    public RibbonClientHttpRequestFactory ribbonClientHttpRequestFactory() {
+        return new RibbonClientHttpRequestFactory(springClientFactory());
+    }
+
 	@Bean
 	public SpringClientFactory springClientFactory() {
 		SpringClientFactory factory = new SpringClientFactory();

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/ribbon/RibbonClientHttpRequestFactory.java

@@ -0,0 +1,154 @@
+/*
+ * Copyright 2013-2015 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.cloud.netflix.ribbon;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.URI;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.cloud.client.ServiceInstance;
+import org.springframework.cloud.client.loadbalancer.LoadBalancerInterceptor;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.client.AbstractClientHttpRequest;
+import org.springframework.http.client.AbstractClientHttpResponse;
+import org.springframework.http.client.ClientHttpRequest;
+import org.springframework.http.client.ClientHttpRequestFactory;
+import org.springframework.http.client.ClientHttpResponse;
+
+import com.netflix.client.config.IClientConfig;
+import com.netflix.client.http.HttpRequest;
+import com.netflix.client.http.HttpResponse;
+import com.netflix.niws.client.http.RestClient;
+
+/**
+ * @author Spencer Gibb
+ */
+public class RibbonClientHttpRequestFactory implements ClientHttpRequestFactory {
+
+	private final SpringClientFactory clientFactory;
+
+	public RibbonClientHttpRequestFactory(SpringClientFactory clientFactory) {
+		this.clientFactory = clientFactory;
+	}
+
+	@Override
+	@SuppressWarnings("deprecation")
+	public ClientHttpRequest createRequest(URI uri, HttpMethod httpMethod)
+			throws IOException {
+		//@formatter:off
+		ServiceInstance instance = LoadBalancerInterceptor.getThreadLocalServiceInstance();
+		IClientConfig clientConfig = clientFactory.getClientConfig(instance.getServiceId());
+		RestClient client = clientFactory.getClient(instance.getServiceId(), RestClient.class);
+		HttpRequest request = HttpRequest.newBuilder()
+                .uri(uri)
+                .verb(HttpRequest.Verb.valueOf(httpMethod.name()))
+                .build();
+        //@formatter:on
+		return new RibbonHttpRequest(request, client, clientConfig);
+	}
+
+	public class RibbonHttpRequest extends AbstractClientHttpRequest {
+
+		private HttpRequest request;
+		private RestClient client;
+		private IClientConfig config;
+
+		@SuppressWarnings("deprecation")
+		public RibbonHttpRequest(HttpRequest request, RestClient client,
+				IClientConfig config) {
+			this.request = request;
+			this.client = client;
+			this.config = config;
+			request.getHeaders().putAll(getHeaders());
+		}
+
+		@Override
+		public HttpMethod getMethod() {
+			return HttpMethod.valueOf(request.getVerb().name());
+		}
+
+		@Override
+		public URI getURI() {
+			return request.getUri();
+		}
+
+		@Override
+		protected OutputStream getBodyInternal(HttpHeaders headers) throws IOException {
+			throw new RuntimeException("Not implemented");
+		}
+
+		@Override
+		protected ClientHttpResponse executeInternal(HttpHeaders headers)
+				throws IOException {
+			HttpResponse response;
+			try {
+				response = client.execute(request, config);
+				return new RibbonHttpResponse(response);
+			}
+			catch (Exception e) {
+				throw new IOException(e);
+			}
+		}
+	}
+
+	public class RibbonHttpResponse extends AbstractClientHttpResponse {
+
+		private HttpResponse response;
+		private HttpHeaders httpHeaders;
+
+		public RibbonHttpResponse(HttpResponse response) {
+			this.response = response;
+			this.httpHeaders = new HttpHeaders();
+			List<Map.Entry<String, String>> headers = response.getHttpHeaders()
+					.getAllHeaders();
+			for (Map.Entry<String, String> header : headers) {
+				this.httpHeaders.add(header.getKey(), header.getValue());
+			}
+		}
+
+		@Override
+		public InputStream getBody() throws IOException {
+			return response.getInputStream();
+		}
+
+		@Override
+		public HttpHeaders getHeaders() {
+			return this.httpHeaders;
+		}
+
+		@Override
+		public int getRawStatusCode() throws IOException {
+			return response.getStatus();
+		}
+
+		@Override
+		public String getStatusText() throws IOException {
+			return HttpStatus.valueOf(response.getStatus()).name();
+		}
+
+		@Override
+		public void close() {
+			response.close();
+		}
+
+	}
+}