Download speed smoothing; add referer to fix MengSky download issues.

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>

src/itdelatrisu/opsu/downloads/Download.java

@@ -33,6 +33,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
+import java.util.Map;
 
 import org.newdawn.slick.util.Log;
 
@@ -98,6 +99,9 @@ public interface DownloadListener {
 	/** The download listener. */
 	private DownloadListener listener;
 
+	/** The additional HTTP request headers. */
+	private Map<String, String> requestHeaders;
+
 	/** The readable byte channel. */
 	private ReadableByteChannelWrapper rbc;
 
@@ -122,6 +126,12 @@ public interface DownloadListener {
 	/** Last calculated ETA string. */
 	private String lastTimeRemaining;
 
+	/** EWMA download speed. */
+	private long avgDownloadSpeed = 0;
+
+	/** EWMA smoothing factor (alpha) for computing average download speed. */
+	private static final double DOWNLOAD_SPEED_SMOOTHING = 0.25;
+
 	/**
 	 * Constructor.
 	 * @param remoteURL the download URL
@@ -165,6 +175,12 @@ public Download(String remoteURL, String localPath, String rename) {
 	 */
 	public void setListener(DownloadListener listener) { this.listener = listener; }
 
+	/**
+	 * Sets additional HTTP headers to use in the download request.
+	 * @param headers the map of headers (key -> value)
+	 */
+	public void setRequestHeaders(Map<String, String> headers) { this.requestHeaders = headers; }
+
 	/**
 	 * Starts the download from the "waiting" status.
 	 * @return the started download thread, or {@code null} if none started
@@ -194,6 +210,10 @@ public void run() {
 						// http://download.java.net/jdk7u2/docs/technotes/guides/deployment/deployment-guide/upgrade-guide/article-17.html
 						conn.setInstanceFollowRedirects(false);
 						conn.setRequestProperty("User-Agent", "Mozilla/5.0...");
+						if (requestHeaders != null) {
+							for (Map.Entry<String, String> entry : requestHeaders.entrySet())
+								conn.setRequestProperty(entry.getKey(), entry.getValue());
+						}
 
 						// check for redirect
 						int status = conn.getResponseCode();
@@ -369,6 +389,7 @@ private void updateReadSoFar() {
 		if (status != Status.DOWNLOADING) {
 			this.lastDownloadSpeed = null;
 			this.lastTimeRemaining = null;
+			this.avgDownloadSpeed = 0;
 			return;
 		}
 
@@ -378,13 +399,16 @@ private void updateReadSoFar() {
 			long readSoFarTime = System.currentTimeMillis();
 			long dlspeed = (readSoFar - lastReadSoFar) * 1000 / (readSoFarTime - lastReadSoFarTime);
 			if (dlspeed > 0) {
-				this.lastDownloadSpeed = String.format("%s/s", Utils.bytesToString(dlspeed));
-				long t = (contentLength - readSoFar) / dlspeed;
+				this.avgDownloadSpeed = (avgDownloadSpeed == 0) ? dlspeed :
+					(long) (DOWNLOAD_SPEED_SMOOTHING * dlspeed + (1 - DOWNLOAD_SPEED_SMOOTHING) * avgDownloadSpeed);
+				this.lastDownloadSpeed = String.format("%s/s", Utils.bytesToString(avgDownloadSpeed));
+				long t = (contentLength - readSoFar) / avgDownloadSpeed;
 				if (t >= 3600)
 					this.lastTimeRemaining = String.format("%dh%dm%ds", t / 3600, (t / 60) % 60, t % 60);
 				else
 					this.lastTimeRemaining = String.format("%dm%ds", t / 60, t % 60);
 			} else {
+				this.avgDownloadSpeed = 0;
 				this.lastDownloadSpeed = String.format("%s/s", Utils.bytesToString(0));
 				this.lastTimeRemaining = "?";
 			}

src/itdelatrisu/opsu/downloads/DownloadNode.java

@@ -284,6 +284,7 @@ public void error() {
 				UI.getNotificationManager().sendNotification("Download failed due to a connection error.", Color.red);
 			}
 		});
+		download.setRequestHeaders(server.getDownloadRequestHeaders());
 		this.download = download;
 		if (Options.useUnicodeMetadata())  // load glyphs
 			Fonts.loadGlyphs(Fonts.LARGE, getTitle());

src/itdelatrisu/opsu/downloads/servers/DownloadServer.java

@@ -21,6 +21,7 @@
 import itdelatrisu.opsu.downloads.DownloadNode;
 
 import java.io.IOException;
+import java.util.Map;
 
 /**
  * Abstract class for beatmap download servers.
@@ -76,6 +77,12 @@ public String getPreviewURL(int beatmapSetID) {
 		return String.format(PREVIEW_URL, beatmapSetID);
 	}
 
+	/**
+	 * Returns any HTTP request headers that should be set in the download request.
+	 * @return the map of headers (key -> value), or null if none
+	 */
+	public Map<String, String> getDownloadRequestHeaders() { return null; }
+
 	@Override
 	public String toString() { return getName(); }
 }

src/itdelatrisu/opsu/downloads/servers/MengSkyServer.java

@@ -27,6 +27,8 @@
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLEncoder;
+import java.util.HashMap;
+import java.util.Map;
 
 import org.json.JSONArray;
 import org.json.JSONException;
@@ -46,6 +48,9 @@ public class MengSkyServer extends DownloadServer {
 	/** Formatted search URL: {@code query,page,unranked,approved,qualified} */
 	private static final String SEARCH_URL = "http://osu.mengsky.net/api/beatmapinfo?query=%s&page=%d&ranked=1&unrank=%d&approved=%d&qualified=%d";
 
+	/** Referer URL. */
+	private static final String REFERER_URL = "http://osu.mengsky.net/";
+
 	/** Maximum beatmaps displayed per page. */
 	private static final int PAGE_LIMIT = 20;
 
@@ -119,4 +124,11 @@ public DownloadNode[] resultList(String query, int page, boolean rankedOnly) thr
 
 	@Override
 	public int totalResults() { return totalResults; }
+
+	@Override
+	public Map<String, String> getDownloadRequestHeaders() {
+		Map<String, String> headers = new HashMap<String, String>();
+		headers.put("Referer", REFERER_URL);
+		return headers;
+	}
 }