/*

  * 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.

  */

 package org.apache.any23.http;

 import org.apache.commons.httpclient.Header;

 import org.apache.commons.httpclient.HostConfiguration;

 import org.apache.commons.httpclient.HttpClient;

 import org.apache.commons.httpclient.HttpConnectionManager;

 import org.apache.commons.httpclient.MultiThreadedHttpConnectionManager;

 import org.apache.commons.httpclient.methods.GetMethod;

 import org.apache.commons.httpclient.params.HttpConnectionManagerParams;

 import java.io.ByteArrayInputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URI;

 import java.net.URISyntaxException;

 import java.net.URLEncoder;

 import java.util.ArrayList;

 import java.util.List;

 /**

  * Opens an {@link InputStream} on an HTTP URI. Is configured

  * with sane values for timeouts, default headers and so on.

  *

  * @author Paolo Capriotti

  * @author Richard Cyganiak (richard@cyganiak.de)

  */

 public class DefaultHTTPClient implements HTTPClient {

     private final MultiThreadedHttpConnectionManager manager = new MultiThreadedHttpConnectionManager();

     private HTTPClientConfiguration configuration;

     private HttpClient client = null;

     private long _contentLength = -1;

     private String actualDocumentURI = null;

     private String contentType = null;

     public void init(HTTPClientConfiguration configuration) {

         if(configuration == null) throw new NullPointerException("Illegal configuration, cannot be null.");

         this.configuration = configuration;

     }

     /**

      *

      * Opens an {@link java.io.InputStream} from a given URI.

      * It follows redirects.

      *

      * @param uri to be opened

      * @return {@link java.io.InputStream}

      * @throws IOException

      */

     public InputStream openInputStream(String uri) throws IOException {

         GetMethod method = null;

         try {

             ensureClientInitialized();

             String uriStr = null;

             try {

                 URI uriObj = new URI(uri);

                 // [scheme:][//authority][path][?query][#fragment]

                 final String path = uriObj.getPath();

                 final String query = uriObj.getQuery();

                 final String fragment = uriObj.getFragment();

                 uriStr = String.format(

                         "%s://%s%s%s%s%s%s",

                         uriObj.getScheme(),

                         uriObj.getAuthority(),

                         path != null ? URLEncoder.encode(path, "UTF-8").replaceAll("%2F", "/") : "",

                         query == null ? "" : "?",

                         query != null ? URLEncoder.encode(query, "UTF-8")

                                 .replaceAll("%3D", "=")

                                 .replaceAll("%26", "&") 

                             :

                             "",

                         fragment == null ? "" : "#",

                         fragment != null ? URLEncoder.encode(fragment, "UTF-8") : ""

                 );

             } catch (URISyntaxException e) {

                 throw new IllegalArgumentException("Invalid URI string.", e);

             }

             method = new GetMethod(uriStr);

             method.setFollowRedirects(true);

             client.executeMethod(method);

             _contentLength = method.getResponseContentLength();

             final Header contentTypeHeader = method.getResponseHeader("Content-Type");

             contentType = contentTypeHeader == null ? null : contentTypeHeader.getValue();

             if (method.getStatusCode() != 200) {

                 throw new IOException(

                         "Failed to fetch " + uri + ": " + method.getStatusCode() + " " + method.getStatusText()

                 );

             }

             actualDocumentURI = method.getURI().toString();

             byte[] response = method.getResponseBody();

             return new ByteArrayInputStream(response);

         } finally {

             if (method != null) {

                 method.releaseConnection();

             }

         }

     }

     /**

      * Shuts down the connection manager.

      */

     public void close() {

         manager.shutdown();

     }

     public long getContentLength() {

         return _contentLength;

     }

     public String getActualDocumentURI() {

         return actualDocumentURI;

     }

     public String getContentType() {

         return contentType;

     }

     protected int getConnectionTimeout() {

         return configuration.getDefaultTimeout();

     }

     protected int getSoTimeout() {

         return configuration.getDefaultTimeout();

     }

     private void ensureClientInitialized() {

         if(configuration == null) throw new IllegalStateException("client must be initialized first.");

         if (client != null) return;

         client = new HttpClient(manager);

         HttpConnectionManager connectionManager = client.getHttpConnectionManager();

         HttpConnectionManagerParams params = connectionManager.getParams();

         params.setConnectionTimeout(configuration.getDefaultTimeout());

         params.setSoTimeout(configuration.getDefaultTimeout());

         params.setMaxTotalConnections(configuration.getMaxConnections());

         HostConfiguration hostConf = client.getHostConfiguration();

         List<Header> headers = new ArrayList<Header>();

         headers.add(new Header("User-Agent", configuration.getUserAgent()));

         if (configuration.getAcceptHeader() != null) {

             headers.add(new Header("Accept", configuration.getAcceptHeader()));

         }

         headers.add(new Header("Accept-Language", "en-us,en-gb,en,*;q=0.3"));

         headers.add(new Header("Accept-Charset", "utf-8,iso-8859-1;q=0.7,*;q=0.5"));

         // headers.add(new Header("Accept-Encoding", "x-gzip, gzip"));

         hostConf.getParams().setParameter("http.default-headers", headers);

     }

 }