org.spoutcraft.client.io.MirrorUtils.java Source code

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Here is the source code for org.spoutcraft.client.io.MirrorUtils.java

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/*
 * This file is part of Spoutcraft (http://www.spout.org/).
 *
 * Spoutcraft is licensed under the SpoutDev License Version 1.
 *
 * Spoutcraft is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * In addition, 180 days after any changes are published, you can use the
 * software, incorporating those changes, under the terms of the MIT license,
 * as described in the SpoutDev License Version 1.
 *
 * Spoutcraft 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License,
 * the MIT license and the SpoutDev license version 1 along with this program.
 * If not, see <http://www.gnu.org/licenses/> for the GNU Lesser General Public
 * License and see <http://www.spout.org/SpoutDevLicenseV1.txt> for the full license,
 * including the MIT license.
 */
package org.spoutcraft.client.io;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Random;
import java.util.Set;

import org.apache.commons.io.IOUtils;

import org.bukkit.util.config.Configuration;

public class MirrorUtils {
    private static boolean updated = false;
    private static File mirrorsYML = new File(FileUtil.getSpoutcraftDirectory(), "mirrors.yml");
    private static final Random rand = new Random();

    static {
        updated = mirrorsYML.exists();
    }

    public static String getMirrorUrl(String mirrorURI, String fallbackUrl) {
        try {
            Map<String, Integer> mirrors = getMirrors();
            Set<Entry<String, Integer>> set = mirrors.entrySet();

            ArrayList<String> goodMirrors = new ArrayList<String>(mirrors.size());
            Iterator<Entry<String, Integer>> iterator = set.iterator();
            while (iterator.hasNext()) {
                Entry<String, Integer> e = iterator.next();
                String mirror = "http://" + e.getKey() + "/" + mirrorURI;
                if (isAddressReachable(mirror)) {
                    goodMirrors.add(e.getKey());
                }
            }

            //safe fast return
            if (goodMirrors.size() == 1) {
                return "http://" + goodMirrors.get(0) + "/" + mirrorURI;
            }

            //the for loop may fail if random numbers are unlucky, in which case we want to try again
            while (goodMirrors.size() > 0) {
                int random = rand.nextInt(10 * mirrors.size());
                int index = random / 10;
                for (int i = index; i < goodMirrors.size() + index; i++) {
                    int j = i;
                    if (j >= goodMirrors.size())
                        j -= goodMirrors.size();
                    int roll = rand.nextInt(100);
                    int chance = mirrors.get(goodMirrors.get(j));
                    if (roll < chance) {
                        String mirror = "http://" + goodMirrors.get(j) + "/" + mirrorURI;
                        return mirror;
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return fallbackUrl;
    }

    @SuppressWarnings("unchecked")
    public static Map<String, Integer> getMirrors() {
        Configuration config = getMirrorsYML();
        return (Map<String, Integer>) config.getProperty("mirrors");
    }

    public static boolean isAddressReachable(String url) {
        try {
            URL test = new URL(url);
            HttpURLConnection.setFollowRedirects(false);
            HttpURLConnection urlConnect = (HttpURLConnection) test.openConnection();
            urlConnect.setRequestMethod("HEAD");
            return (urlConnect.getResponseCode() == HttpURLConnection.HTTP_OK);
        } catch (Exception e) {
            return false;
        }
    }

    public static Configuration getMirrorsYML() {
        updateMirrorsYMLCache();
        Configuration config = new Configuration(mirrorsYML);
        config.load();
        return config;
    }

    public static void updateMirrorsYMLCache() {
        if (!updated) {
            try {
                URL url = new URL("http://get.spout.org/mirrors.yml");
                HttpURLConnection con = (HttpURLConnection) (url.openConnection());
                System.setProperty("http.agent", "");
                con.setRequestProperty("User-Agent",
                        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.100 Safari/534.30");
                OutputStream os = new FileOutputStream(mirrorsYML);
                InputStream is = con.getInputStream();
                IOUtils.copy(is, os);
                is.close();
                os.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            updated = true;
        }
    }
}