/*

  * This file is part of dependency-check-core.

  *

  * Dependency-check-core is free software: you can redistribute it and/or modify it

  * under the terms of the GNU General Public License as published by the Free

  * Software Foundation, either version 3 of the License, or (at your option) any

  * later version.

  *

  * Dependency-check-core is distributed in the hope that it will be useful, but

  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more

  * details.

  *

  * You should have received a copy of the GNU General Public License along with

  * dependency-check-core. If not, see http://www.gnu.org/licenses/.

  *

  * Copyright (c) 2012 Jeremy Long. All Rights Reserved.

  */

 package org.owasp.dependencycheck.utils;

 import java.io.BufferedOutputStream;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.HttpURLConnection;

 import java.net.InetSocketAddress;

 import java.net.Proxy;

 import java.net.SocketAddress;

 import java.net.URL;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 import java.util.zip.GZIPInputStream;

 import java.util.zip.InflaterInputStream;

 /**

  * A utility to download files from the Internet.

  *

  * @author Jeremy Long (jeremy.long@owasp.org)

  */

 public final class Downloader {

     /**

      * Private constructor for utility class.

      */

     private Downloader() {

     }

     /**

      * Retrieves a file from a given URL and saves it to the outputPath.

      *

      * @param url the URL of the file to download.

      * @param outputPath the path to the save the file to.

      * @throws DownloadFailedException is thrown if there is an error

      * downloading the file.

      */

     public static void fetchFile(URL url, String outputPath) throws DownloadFailedException {

         fetchFile(url, outputPath, false);

     }

     /**

      * Retrieves a file from a given URL and saves it to the outputPath.

      *

      * @param url the URL of the file to download.

      * @param outputPath the path to the save the file to.

      * @param unzip true/false indicating that the file being retrieved is

      * gzipped and if true, should be uncompressed before writing to the file.

      * @throws DownloadFailedException is thrown if there is an error

      * downloading the file.

      */

     public static void fetchFile(URL url, String outputPath, boolean unzip) throws DownloadFailedException {

         final File f = new File(outputPath);

         fetchFile(url, f, unzip);

     }

     /**

      * Retrieves a file from a given URL and saves it to the outputPath.

      *

      * @param url the URL of the file to download.

      * @param outputPath the path to the save the file to.

      * @throws DownloadFailedException is thrown if there is an error

      * downloading the file.

      */

     public static void fetchFile(URL url, File outputPath) throws DownloadFailedException {

         fetchFile(url, outputPath, false);

     }

     /**

      * Retrieves a file from a given URL and saves it to the outputPath.

      *

      * @param url the URL of the file to download.

      * @param outputPath the path to the save the file to.

      * @param unzip true/false indicating that the file being retrieved is

      * gzipped and if true, should be uncompressed before writing to the file.

      * @throws DownloadFailedException is thrown if there is an error

      * downloading the file.

      */

     public static void fetchFile(URL url, File outputPath, boolean unzip) throws DownloadFailedException {

         HttpURLConnection conn = null;

         try {

             conn = Downloader.getConnection(url);

             conn.setRequestProperty("Accept-Encoding", "gzip, deflate");

             conn.connect();

         } catch (IOException ex) {

             try {

                 if (conn != null) {

                     conn.disconnect();

                 }

             } finally {

                 conn = null;

             }

             throw new DownloadFailedException("Error downloading file.", ex);

         }

         final String encoding = conn.getContentEncoding();

         BufferedOutputStream writer = null;

         InputStream reader = null;

         try {

             if (unzip || (encoding != null && "gzip".equalsIgnoreCase(encoding))) {

                 reader = new GZIPInputStream(conn.getInputStream());

             } else if (encoding != null && "deflate".equalsIgnoreCase(encoding)) {

                 reader = new InflaterInputStream(conn.getInputStream());

             } else {

                 reader = conn.getInputStream();

             }

             writer = new BufferedOutputStream(new FileOutputStream(outputPath));

             final byte[] buffer = new byte[4096];

             int bytesRead;

             while ((bytesRead = reader.read(buffer)) > 0) {

                 writer.write(buffer, 0, bytesRead);

             }

         } catch (Exception ex) {

             throw new DownloadFailedException("Error saving downloaded file.", ex);

         } finally {

             if (writer != null) {

                 try {

                     writer.close();

                     writer = null;

                 } catch (Exception ex) {

                     Logger.getLogger(Downloader.class.getName()).log(Level.FINEST,

                             "Error closing the writer in Downloader.", ex);

                 }

             }

             if (reader != null) {

                 try {

                     reader.close();

                     reader = null;

                 } catch (Exception ex) {

                     Logger.getLogger(Downloader.class.getName()).log(Level.FINEST,

                             "Error closing the reader in Downloader.", ex);

                 }

             }

             try {

                 conn.disconnect();

             } finally {

                 conn = null;

             }

         }

     }

     /**

      * Makes an HTTP Head request to retrieve the last modified date of the

      * given URL.

      *

      * @param url the URL to retrieve the timestamp from

      * @return an epoch timestamp

      * @throws DownloadFailedException is thrown if an exception occurs making

      * the HTTP request

      */

     public static long getLastModified(URL url) throws DownloadFailedException {

         HttpURLConnection conn = null;

         long timestamp = 0;

         try {

             conn = Downloader.getConnection(url);

             conn.setRequestMethod("HEAD");

             conn.connect();

             timestamp = conn.getLastModified();

         } catch (Exception ex) {

             throw new DownloadFailedException("Error making HTTP HEAD request.", ex);

         } finally {

             if (conn != null) {

                 try {

                     conn.disconnect();

                 } finally {

                     conn = null;

                 }

             }

         }

         return timestamp;

     }

     /**

      * Utility method to get an HttpURLConnection. If the app is configured to

      * use a proxy this method will retrieve the proxy settings and use them

      * when setting up the connection.

      *

      * @param url the url to connect to

      * @return an HttpURLConnection

      * @throws DownloadFailedException thrown if there is an exception

      */

     private static HttpURLConnection getConnection(URL url) throws DownloadFailedException {

         HttpURLConnection conn = null;

         Proxy proxy = null;

         final String proxyUrl = Settings.getString(Settings.KEYS.PROXY_URL);

         try {

             if (proxyUrl != null) {

                 final int proxyPort = Settings.getInt(Settings.KEYS.PROXY_PORT);

                 final SocketAddress addr = new InetSocketAddress(proxyUrl, proxyPort);

                 proxy = new Proxy(Proxy.Type.HTTP, addr);

                 conn = (HttpURLConnection) url.openConnection(proxy);

             } else {

                 conn = (HttpURLConnection) url.openConnection();

             }

             //added a default timeout of 20000

             //if (Settings.getString(Settings.KEYS.CONNECTION_TIMEOUT) != null) {

             final int timeout = Settings.getInt(Settings.KEYS.CONNECTION_TIMEOUT, 60000);

             conn.setConnectTimeout(timeout);

             //}

         } catch (IOException ex) {

             if (conn != null) {

                 try {

                     conn.disconnect();

                 } finally {

                     conn = null;

                 }

             }

             throw new DownloadFailedException("Error getting connection.", ex);

         }

         return conn;

     }

 }