NewPipe/app/src/main/java/org/schabi/newpipe/Downloader.java

package org.schabi.newpipe;

import org.schabi.newpipe.extractor.exceptions.ReCaptchaException;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.net.ssl.HttpsURLConnection;


/**
 * Created by Christian Schabesberger on 28.01.16.
 *
 * Copyright (C) Christian Schabesberger 2016 <chris.schabesberger@mailbox.org>
 * Downloader.java is part of NewPipe.
 *
 * NewPipe 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.
 *
 * NewPipe 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 NewPipe.  If not, see <http://www.gnu.org/licenses/>.
 */

public class Downloader implements org.schabi.newpipe.extractor.Downloader {
    
    private static final String USER_AGENT = "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:43.0) Gecko/20100101 Firefox/43.0";
    private static String mCookies = "";

    private static Downloader instance = null;

    private Downloader() {}

    public static Downloader getInstance() {
        if(instance == null) {
            synchronized (Downloader.class) {
                if (instance == null) {
                    instance = new Downloader();
                }
            }
        }
        return instance;
    }

    public static synchronized void setCookies(String cookies) {
        Downloader.mCookies = cookies;
    }

    public static synchronized String getCookies() {
        return Downloader.mCookies;
    }

    /**Download the text file at the supplied URL as in download(String),
     * but set the HTTP header field "Accept-Language" to the supplied string.
     * @param siteUrl the URL of the text file to return the contents of
     * @param language the language (usually a 2-character code) to set as the preferred language
     * @return the contents of the specified text file*/
    public String download(String siteUrl, String language) throws IOException, ReCaptchaException {
        Map<String, String> requestProperties = new HashMap<>();
        requestProperties.put("Accept-Language", language);
        return download(siteUrl, requestProperties);
    }


    /**Download the text file at the supplied URL as in download(String),
     * but set the HTTP header field "Accept-Language" to the supplied string.
     * @param siteUrl the URL of the text file to return the contents of
     * @param customProperties set request header properties
     * @return the contents of the specified text file
     * @throws IOException*/
    public String download(String siteUrl, Map<String, String> customProperties) throws IOException, ReCaptchaException {
        URL url = new URL(siteUrl);
        HttpsURLConnection con = (HttpsURLConnection) url.openConnection();
        Iterator it = customProperties.entrySet().iterator();
        while(it.hasNext()) {
            Map.Entry pair = (Map.Entry)it.next();
            con.setRequestProperty((String)pair.getKey(), (String)pair.getValue());
        }
        return dl(con);
    }

    /**Common functionality between download(String url) and download(String url, String language)*/
    private static String dl(HttpsURLConnection con) throws IOException, ReCaptchaException {
        StringBuilder response = new StringBuilder();
        BufferedReader in = null;

        try {
            con.setRequestMethod("GET");
            con.setRequestProperty("User-Agent", USER_AGENT);

            if (getCookies().length() > 0) {
                con.setRequestProperty("Cookie", getCookies());
            }

            in = new BufferedReader(
                    new InputStreamReader(con.getInputStream()));
            String inputLine;

            while((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
        } catch(UnknownHostException uhe) {//thrown when there's no internet connection
            throw new IOException("unknown host or no network", uhe);
            //Toast.makeText(getActivity(), uhe.getMessage(), Toast.LENGTH_LONG).show();
        } catch(Exception e) {
            /*
             * HTTP 429 == Too Many Request
             * Receive from Youtube.com = ReCaptcha challenge request
             * See : https://github.com/rg3/youtube-dl/issues/5138
             */
            if (con.getResponseCode() == 429) {
                throw new ReCaptchaException("reCaptcha Challenge requested");
            }
            throw new IOException(e);
        } finally {
            if(in != null) {
                in.close();
            }
        }

        return response.toString();
    }

    /**Download (via HTTP) the text file located at the supplied URL, and return its contents.
     * Primarily intended for downloading web pages.
     * @param siteUrl the URL of the text file to download
     * @return the contents of the specified text file*/
    public String download(String siteUrl) throws IOException, ReCaptchaException {
        URL url = new URL(siteUrl);
        HttpsURLConnection con = (HttpsURLConnection) url.openConnection();
        //HttpsURLConnection con = NetCipher.getHttpsURLConnection(url);
        return dl(con);
    }
}