package us.codecraft.webmagic.downloader;
   
   import java.net.URI;
   
   import org.apache.http.HttpRequest;
   import org.apache.http.HttpResponse;
   import org.apache.http.ProtocolException;
   import org.apache.http.client.methods.HttpGet;
   import org.apache.http.client.methods.HttpPost;
  import org.apache.http.client.methods.HttpRequestWrapper;
  import org.apache.http.client.methods.HttpUriRequest;
  import org.apache.http.impl.client.LaxRedirectStrategy;
  import org.apache.http.protocol.HttpContext;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   *支持post 302跳转策略实现类
   *HttpClient默认跳转：httpClientBuilder.setRedirectStrategy(new LaxRedirectStrategy());
   *上述代码在post/redirect/post这种情况下不会传递原有请求的数据信息。所以参考了下SeimiCrawler这个项目的重定向策略。
   *原代码地址：https://github.com/zhegexiaohuozi/SeimiCrawler/blob/master/project/src/main/java/cn/wanghaomiao/seimi/http/hc/SeimiRedirectStrategy.java
   */
  public class CustomRedirectStrategy extends LaxRedirectStrategy {
      private Logger logger = LoggerFactory.getLogger(getClass());
  
      @Override
      public HttpUriRequest getRedirect(HttpRequest request, HttpResponse response, HttpContext context) throws ProtocolException {
          URI uri = getLocationURI(request, response, context);
          String method = request.getRequestLine().getMethod();
          if ("post".equalsIgnoreCase(method)) {
              try {
                  HttpRequestWrapper httpRequestWrapper = (HttpRequestWrapper) request;
                  httpRequestWrapper.setURI(uri);
                  httpRequestWrapper.removeHeaders("Content-Length");
                  return httpRequestWrapper;
              } catch (Exception e) {
                  logger.error("强转为HttpRequestWrapper出错");
              }
              return new HttpPost(uri);
          } else {
              return new HttpGet(uri);
          }
      }
  }