UpdateChecker.java

package com.twemyeez.picklr.utils;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;

import net.minecraft.util.EnumChatFormatting;

import com.twemyeez.picklr.Picklr;

public class UpdateChecker {
	/*
	 * This class handles checking for updates, and presenting them to the user.
	 */

	/*
	 * We don't want to run an update every single time the user does a command.
	 * Therefore, we cache the server result here and used this cached result
	 * instead. It's only reloaded when the modification initialises, so they'd
	 * need to restart Minecraft for a new update to show. However, this is
	 * unlikely to be an issue for most users, as very few people leave
	 * Minecraft open forever.
	 */
	private static String cachedNewRelease = Picklr.VERSION;

	/*
	 * Update messages can be annoying, so we only display them once every 5
	 * minutes maximum. Therefore, this is used to store the last time (in
	 * milliseconds) that there was a message given to the user. Default is 0,
	 * because we should always show the first update
	 */
	private static Long lastMessage = 0L;

	/*
	 * This method will be called whenever the user runs a command/function in
	 * PickledChat
	 */
	public static void checkForUpdate() {
		/*
		 * We calculate the system time 5 minutes ago, to make sure we don't
		 * show the message too often
		 */
		Long thresholdTime = System.currentTimeMillis() - 5 * 60 * 1000;

		// Debug printing
		System.out.println("[" + Picklr.MODID + "] Version is "
				+ Picklr.VERSION + " and detected latest version is "
				+ cachedNewRelease);

		/*
		 * If their version isn't up to date and it's been over 5 minutes since
		 * the last message
		 */
		if (!Picklr.VERSION.equals(cachedNewRelease)
				&& thresholdTime > lastMessage) {
			CommonUtils
					.sendFormattedChat(
							true,
							"It appears the mod is not up to date. Please check the thread for exciting new updates!",
							EnumChatFormatting.RED, true);
		}
	}

	/*
	 * This method will deal with the async web request to retrieve the latest
	 * Picklr Version
	 */
	public static void requestLatestVersion() {
		// Start a new thread to do the web request

		new Thread(new Runnable() {

			@Override
			public void run() {
				/*
				 * We run this entire block in a try, because if it fails, it is
				 * unlikely any following step will be successful
				 */

				try {
					// Define the update URL
					URL website = new URL(
							"http://picklr.me/api/v1/version.txt");

					// Open a connection to the website
					URLConnection connection = website.openConnection();
					connection.setConnectTimeout(1500);
					connection.setReadTimeout(1500);

					// This header eliminates some issues with user agent
					// filtering
					connection
							.addRequestProperty("User-Agent",
									"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)");

					// Read the input
					BufferedReader input = new BufferedReader(
							new InputStreamReader(connection.getInputStream()));

					// Make a stringbuilder
					StringBuilder responseBuilder = new StringBuilder();

					// Define a string to temporarily hold the input lines
					String inputLine = null;

					// Build the output from each line of the input
					while ((inputLine = input.readLine()) != null) {
						responseBuilder.append(inputLine);
					}

					// Close the buffered reader
					input.close();

					// Save the retrieved version
					UpdateChecker.cachedNewRelease = responseBuilder.toString();
				} catch (Exception e) {
					// The current version has a safe default, so we'll just
					// print a stack trace
					e.printStackTrace();
				}

			}
		}).start();
	}
}