/*
    * ====================================================================
    * 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.hc.client5.http.examples.fluent;
  
  import java.io.IOException;
  import java.nio.charset.Charset;
  import java.nio.charset.StandardCharsets;
  
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  import javax.xml.parsers.ParserConfigurationException;
  
  import org.apache.hc.client5.http.ClientProtocolException;
  import org.apache.hc.client5.http.HttpResponseException;
  import org.apache.hc.client5.http.fluent.Request;
  import org.apache.hc.core5.http.ClassicHttpResponse;
  import org.apache.hc.core5.http.ContentType;
  import org.apache.hc.core5.http.HttpEntity;
  import org.apache.hc.core5.http.HttpStatus;
  import org.apache.hc.core5.http.io.HttpClientResponseHandler;
  import org.w3c.dom.Document;
  import org.xml.sax.SAXException;
  
  /**
   * This example demonstrates how the HttpClient fluent API can be used to handle HTTP responses
   * without buffering content body in memory.
   */
  public class FluentResponseHandling {
  
      public static void main(final String... args)throws Exception {
          final Document result = Request.get("http://somehost/content")
                  .execute().handleResponse(new HttpClientResponseHandler<Document>() {
  
              @Override
              public Document handleResponse(final ClassicHttpResponse response) throws IOException {
                  final int status = response.getCode();
                  final HttpEntity entity = response.getEntity();
                  if (status >= HttpStatus.SC_REDIRECTION) {
                      throw new HttpResponseException(status, response.getReasonPhrase());
                  }
                  if (entity == null) {
                      throw new ClientProtocolException("Response contains no content");
                  }
                  final DocumentBuilderFactory dbfac = DocumentBuilderFactory.newInstance();
                  try {
                      final DocumentBuilder docBuilder = dbfac.newDocumentBuilder();
                      final ContentType contentType = ContentType.parseLenient(entity.getContentType());
                      if (!contentType.equals(ContentType.APPLICATION_XML)) {
                          throw new ClientProtocolException("Unexpected content type:" + contentType);
                      }
                      Charset charset = contentType.getCharset();
                      if (charset == null) {
                          charset = StandardCharsets.ISO_8859_1;
                      }
                      return docBuilder.parse(entity.getContent(), charset.name());
                  } catch (final ParserConfigurationException ex) {
                      throw new IllegalStateException(ex);
                  } catch (final SAXException ex) {
                      throw new ClientProtocolException("Malformed XML document", ex);
                  }
              }
  
              });
          // Do something useful with the result
          System.out.println(result);
      }
  
  }