extensions/gae/src/main/java/org/jclouds/gae/ConvertToGaeRequest.java

/**
 *
 * Copyright (C) 2010 Cloud Conscious, LLC. <info@cloudconscious.com>
 *
 * ====================================================================
 * 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.jclouds.gae;

import static com.google.appengine.api.urlfetch.FetchOptions.Builder.disallowTruncate;
import static com.google.common.io.Closeables.closeQuietly;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Map.Entry;

import javax.inject.Singleton;
import javax.ws.rs.core.HttpHeaders;

import org.jclouds.http.HttpRequest;
import org.jclouds.http.HttpUtils;
import org.jclouds.io.Payload;

import com.google.appengine.api.urlfetch.FetchOptions;
import com.google.appengine.api.urlfetch.HTTPHeader;
import com.google.appengine.api.urlfetch.HTTPMethod;
import com.google.appengine.api.urlfetch.HTTPRequest;
import com.google.appengine.repackaged.com.google.common.base.Throwables;
import com.google.common.base.Function;
import com.google.common.collect.LinkedHashMultimap;

/**
 * 
 * @author Adrian Cole
 */
@Singleton
public class ConvertToGaeRequest implements Function<HttpRequest, HTTPRequest> {
   public static final String USER_AGENT = "jclouds/1.0 urlfetch/1.3.5";

   /**
    * byte [] content is replayable and the only content type supportable by GAE. As such, we
    * convert the original request content to a byte array.
    */
   @Override
   public HTTPRequest apply(HttpRequest request) {
      URL url = null;
      try {
         url = request.getEndpoint().toURL();
      } catch (MalformedURLException e) {
         Throwables.propagate(e);
      }

      FetchOptions options = disallowTruncate();
      options.doNotFollowRedirects();

      HTTPRequest gaeRequest = new HTTPRequest(url, HTTPMethod.valueOf(request.getMethod().toString()), options);

      for (String header : request.getHeaders().keySet()) {
         for (String value : request.getHeaders().get(header)) {
            if (!"Transfer-Encoding".equals(header))
               gaeRequest.addHeader(new HTTPHeader(header, value));
         }
      }
      gaeRequest.addHeader(new HTTPHeader(HttpHeaders.USER_AGENT, USER_AGENT));
      /**
       * byte [] content is replayable and the only content type supportable by GAE. As such, we
       * convert the original request content to a byte array.
       */
      if (request.getPayload() != null) {
         InputStream input = request.getPayload().getInput();
         try {
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            request.getPayload().writeTo(out);
            byte[] array = out.toByteArray();
            if (!request.getPayload().isRepeatable()) {
               Payload oldPayload = request.getPayload();
               request.setPayload(array);
               HttpUtils.copy(oldPayload.getContentMetadata(), request.getPayload().getContentMetadata());
            }
            gaeRequest.setPayload(array);
         } catch (IOException e) {
            Throwables.propagate(e);
         } finally {
            closeQuietly(input);
         }
         LinkedHashMultimap<String, String> map = LinkedHashMultimap.create();
         HttpUtils.addContentHeadersFromMetadata(request.getPayload().getContentMetadata(), map);
         for (Entry<String, String> header : map.entries()) {
            gaeRequest.setHeader(new HTTPHeader(header.getKey(), header.getValue()));
         }
      } else {
         gaeRequest.setHeader(new HTTPHeader(HttpHeaders.CONTENT_LENGTH, "0"));
      }
      return gaeRequest;
   }
}