/*
    * ====================================================================
    * 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  
  package org.apache.http.protocol;
  
  import java.io.IOException;
  
  import org.apache.http.Header;
  import org.apache.http.HttpEntity;
  import org.apache.http.HttpException;
  import org.apache.http.HttpRequest;
  import org.apache.http.HttpResponse;
  import org.apache.http.HttpResponseInterceptor;
  import org.apache.http.HttpStatus;
  import org.apache.http.HttpVersion;
  import org.apache.http.ProtocolVersion;
  import org.apache.http.annotation.Immutable;
  
  /**
   * ResponseConnControl is responsible for adding <code>Connection</code> header
   * to the outgoing responses, which is essential for managing persistence of
   * <code>HTTP/1.0</code> connections. This interceptor is recommended for
   * server side protocol processors.
   *
   * @since 4.0
   */
  @Immutable
  public class ResponseConnControl implements HttpResponseInterceptor {
  
      public ResponseConnControl() {
          super();
      }
  
      public void process(final HttpResponse response, final HttpContext context)
              throws HttpException, IOException {
          if (response == null) {
              throw new IllegalArgumentException("HTTP response may not be null");
          }
          if (context == null) {
              throw new IllegalArgumentException("HTTP context may not be null");
          }
          // Always drop connection after certain type of responses
          int status = response.getStatusLine().getStatusCode();
          if (status == HttpStatus.SC_BAD_REQUEST ||
                  status == HttpStatus.SC_REQUEST_TIMEOUT ||
                  status == HttpStatus.SC_LENGTH_REQUIRED ||
                  status == HttpStatus.SC_REQUEST_TOO_LONG ||
                  status == HttpStatus.SC_REQUEST_URI_TOO_LONG ||
                  status == HttpStatus.SC_SERVICE_UNAVAILABLE ||
                  status == HttpStatus.SC_NOT_IMPLEMENTED) {
              response.setHeader(HTTP.CONN_DIRECTIVE, HTTP.CONN_CLOSE);
              return;
          }
          Header explicit = response.getFirstHeader(HTTP.CONN_DIRECTIVE);
          if (explicit != null && HTTP.CONN_CLOSE.equalsIgnoreCase(explicit.getValue())) {
              // Connection persistence explicitly disabled
              return;
          }
          // Always drop connection for HTTP/1.0 responses and below
          // if the content body cannot be correctly delimited
          HttpEntity entity = response.getEntity();
          if (entity != null) {
              ProtocolVersion ver = response.getStatusLine().getProtocolVersion();
              if (entity.getContentLength() < 0 &&
                      (!entity.isChunked() || ver.lessEquals(HttpVersion.HTTP_1_0))) {
                  response.setHeader(HTTP.CONN_DIRECTIVE, HTTP.CONN_CLOSE);
                  return;
              }
          }
          // Drop connection if requested by the client or request was <= 1.0
          HttpRequest request = (HttpRequest)
              context.getAttribute(ExecutionContext.HTTP_REQUEST);
          if (request != null) {
              Header header = request.getFirstHeader(HTTP.CONN_DIRECTIVE);
              if (header != null) {
                 response.setHeader(HTTP.CONN_DIRECTIVE, header.getValue());
             } else if (request.getProtocolVersion().lessEquals(HttpVersion.HTTP_1_0)) {
                 response.setHeader(HTTP.CONN_DIRECTIVE, HTTP.CONN_CLOSE);
             }
         }
     }
 
 }