core/src/main/java/org/jclouds/http/handlers/RedirectionRetryHandler.java

/**
 * Licensed to jclouds, Inc. (jclouds) under one or more
 * contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  jclouds 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.jclouds.http.handlers;

import static java.util.Collections.singletonList;
import static javax.ws.rs.core.HttpHeaders.HOST;
import static org.jclouds.http.HttpUtils.closeClientButKeepContentStream;

import java.net.URI;

import javax.annotation.Resource;
import javax.inject.Named;
import javax.inject.Provider;
import javax.inject.Singleton;
import javax.ws.rs.core.HttpHeaders;
import javax.ws.rs.core.UriBuilder;

import org.jclouds.Constants;
import org.jclouds.http.HttpCommand;
import org.jclouds.http.HttpRequest;
import org.jclouds.http.HttpResponse;
import org.jclouds.http.HttpRetryHandler;
import org.jclouds.http.utils.ModifyRequest;
import org.jclouds.logging.Logger;

import com.google.inject.Inject;

/**
 * Handles Retryable responses with error codes in the 3xx range
 * 
 * @author Adrian Cole
 */
@Singleton
public class RedirectionRetryHandler implements HttpRetryHandler {
   @Inject(optional = true)
   @Named(Constants.PROPERTY_MAX_REDIRECTS)
   protected int retryCountLimit = 5;

   @Resource
   protected Logger logger = Logger.NULL;

   protected final BackoffLimitedRetryHandler backoffHandler;
   protected final Provider<UriBuilder> uriBuilderProvider;

   @Inject
   protected RedirectionRetryHandler(Provider<UriBuilder> uriBuilderProvider, BackoffLimitedRetryHandler backoffHandler) {
      this.backoffHandler = backoffHandler;
      this.uriBuilderProvider = uriBuilderProvider;
   }

   public boolean shouldRetryRequest(HttpCommand command, HttpResponse response) {
      closeClientButKeepContentStream(response);
      String hostHeader = response.getFirstHeaderOrNull(HttpHeaders.LOCATION);
      if (command.incrementRedirectCount() < retryCountLimit && hostHeader != null) {
         URI redirectionUrl = URI.create(hostHeader);

         // if you are sent the same uri, assume there's a transient problem and retry.
         HttpRequest currentRequest = command.getCurrentRequest();
         if (redirectionUrl.equals(currentRequest.getEndpoint()))
            return backoffHandler.shouldRetryRequest(command, response);

         assert redirectionUrl.getPath() != null : "no path in redirect header from: " + response;
         if (!redirectionUrl.isAbsolute()) {
            UriBuilder builder = uriBuilderProvider.get().uri(currentRequest.getEndpoint());
            builder.replacePath(redirectionUrl.getPath());
            if (redirectionUrl.getQuery() != null)
               builder.replaceQuery(redirectionUrl.getQuery());
            redirectionUrl = builder.build();
         }

         if (currentRequest.getFirstHeaderOrNull(HOST) != null && redirectionUrl.getHost() != null) {
            String host = redirectionUrl.getHost();
            if (redirectionUrl.getPort() != -1) {
               host += ":" + redirectionUrl.getPort();
            }
            command.setCurrentRequest(ModifyRequest.replaceHeader(currentRequest, HOST,
                  singletonList(host)).toBuilder().endpoint(redirectionUrl).build());
         } else {
            command.setCurrentRequest(currentRequest.toBuilder().endpoint(redirectionUrl).build());
         }
         return true;
      } else {
         return false;
      }
   }

}