| /** |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.camel.component.jetty; |
| |
| import java.io.IOException; |
| import java.util.Map; |
| import java.util.concurrent.ConcurrentHashMap; |
| import javax.servlet.ServletException; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| |
| import org.apache.camel.AsyncCallback; |
| import org.apache.camel.Exchange; |
| import org.apache.camel.ExchangePattern; |
| import org.apache.camel.component.http.CamelServlet; |
| import org.apache.camel.component.http.HttpConsumer; |
| import org.apache.camel.component.http.HttpMessage; |
| import org.apache.camel.component.http.helper.HttpHelper; |
| import org.apache.camel.impl.DefaultExchange; |
| import org.eclipse.jetty.continuation.Continuation; |
| import org.eclipse.jetty.continuation.ContinuationSupport; |
| |
| /** |
| * Servlet which leverage <a href="http://wiki.eclipse.org/Jetty/Feature/Continuations">Jetty Continuations</a>. |
| * |
| * @version |
| */ |
| public class CamelContinuationServlet extends CamelServlet { |
| |
| static final String EXCHANGE_ATTRIBUTE_NAME = "CamelExchange"; |
| static final String EXCHANGE_ATTRIBUTE_ID = "CamelExchangeId"; |
| |
| private static final long serialVersionUID = 1L; |
| // jetty will by default use 30000 millis as default timeout |
| private Long continuationTimeout; |
| // we must remember expired exchanges as Jetty will initiate a new continuation when we send |
| // back the error when timeout occurred, and thus in the async callback we cannot check the |
| // continuation if it was previously expired. So that's why we have our own map for that |
| private final Map<String, String> expiredExchanges = new ConcurrentHashMap<String, String>(); |
| |
| @Override |
| protected void service(final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException { |
| log.trace("Service: {}", request); |
| |
| // is there a consumer registered for the request. |
| HttpConsumer consumer = resolve(request); |
| if (consumer == null) { |
| response.sendError(HttpServletResponse.SC_NOT_FOUND); |
| return; |
| } |
| |
| final Exchange result = (Exchange) request.getAttribute(EXCHANGE_ATTRIBUTE_NAME); |
| if (result == null) { |
| // no asynchronous result so leverage continuation |
| final Continuation continuation = ContinuationSupport.getContinuation(request); |
| if (continuation.isInitial() && continuationTimeout != null) { |
| // set timeout on initial |
| continuation.setTimeout(continuationTimeout); |
| } |
| |
| // are we suspended and a request is dispatched initially? |
| if (consumer.isSuspended() && continuation.isInitial()) { |
| response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE); |
| return; |
| } |
| |
| if (continuation.isExpired()) { |
| String id = (String) continuation.getAttribute(EXCHANGE_ATTRIBUTE_ID); |
| // remember this id as expired |
| expiredExchanges.put(id, id); |
| log.warn("Continuation expired of exchangeId: {}", id); |
| response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE); |
| return; |
| } |
| |
| // a new request so create an exchange |
| final Exchange exchange = new DefaultExchange(consumer.getEndpoint(), ExchangePattern.InOut); |
| if (consumer.getEndpoint().isBridgeEndpoint()) { |
| exchange.setProperty(Exchange.SKIP_GZIP_ENCODING, Boolean.TRUE); |
| } |
| if (consumer.getEndpoint().isDisableStreamCache()) { |
| exchange.setProperty(Exchange.DISABLE_HTTP_STREAM_CACHE, Boolean.TRUE); |
| } |
| |
| HttpHelper.setCharsetFromContentType(request.getContentType(), exchange); |
| exchange.setIn(new HttpMessage(exchange, request, response)); |
| |
| log.trace("Suspending continuation of exchangeId: {}", exchange.getExchangeId()); |
| continuation.setAttribute(EXCHANGE_ATTRIBUTE_ID, exchange.getExchangeId()); |
| // must suspend before we process the exchange |
| continuation.suspend(); |
| |
| log.trace("Processing request for exchangeId: {}", exchange.getExchangeId()); |
| // use the asynchronous API to process the exchange |
| consumer.getAsyncProcessor().process(exchange, new AsyncCallback() { |
| public void done(boolean doneSync) { |
| // check if the exchange id is already expired |
| boolean expired = expiredExchanges.remove(exchange.getExchangeId()) != null; |
| if (!expired) { |
| log.trace("Resuming continuation of exchangeId: {}", exchange.getExchangeId()); |
| // resume processing after both, sync and async callbacks |
| continuation.setAttribute(EXCHANGE_ATTRIBUTE_NAME, exchange); |
| continuation.resume(); |
| } else { |
| log.warn("Cannot resume expired continuation of exchangeId: {}", exchange.getExchangeId()); |
| } |
| } |
| }); |
| |
| // return to let Jetty continuation to work as it will resubmit and invoke the service |
| // method again when its resumed |
| return; |
| } |
| |
| try { |
| log.trace("Resumed continuation and writing response for exchangeId: {}", result.getExchangeId()); |
| // now lets output to the response |
| consumer.getBinding().writeResponse(result, response); |
| } catch (IOException e) { |
| log.error("Error processing request", e); |
| throw e; |
| } catch (Exception e) { |
| log.error("Error processing request", e); |
| throw new ServletException(e); |
| } |
| } |
| |
| public Long getContinuationTimeout() { |
| return continuationTimeout; |
| } |
| |
| public void setContinuationTimeout(Long continuationTimeout) { |
| this.continuationTimeout = continuationTimeout; |
| } |
| |
| @Override |
| public void destroy() { |
| expiredExchanges.clear(); |
| super.destroy(); |
| } |
| |
| } |