优化网络劫持检测机制

app/src/main/java/com/gh/download/DownloadThread.java

@@ -7,13 +7,19 @@ import android.util.Log;
 import com.gh.common.util.HttpsUtils;
 import com.gh.common.util.Utils;
 
+import org.json.JSONException;
+import org.json.JSONObject;
+
 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.net.HttpURLConnection;
 import java.net.URL;
+import java.net.URLEncoder;
 
 public class DownloadThread extends Thread {
 
@@ -83,7 +89,19 @@ public class DownloadThread extends Thread {
 			}
 			String eTag2 = entry.getETag();
 			if (!TextUtils.isEmpty(eTag2) && !eTag2.equals(eTag)) {
-				//链接被劫持，抛出异常
+				// 链接被劫持，抛出异常
+				if (!entry.isChange()
+						&&"download.ghzhushou.com".equals(new URL(entry.getUrl()).getHost())
+						&& ("apk2.ghzhushou.com".equals(connection.getURL().getHost())
+							|| "apk.ghzhushou.com".equals(connection.getURL().getHost()))) {
+					String newETag = getETag(entry.getUrl());
+					if (!TextUtils.isEmpty(newETag)) {
+						entry.setETag(newETag);
+						entry.setChange(true);
+						download();
+						return;
+					}
+				}
 				Utils.log("eTag = " + eTag);
 				Utils.log("eTag2 = " + eTag2);
 				listener.onStatusChanged(DownloadStatus.hijack, connection.getURL().toString());
@@ -186,6 +204,37 @@ public class DownloadThread extends Thread {
 		return connection;
 	}
 
+	private String getETag(String url) {
+		try {
+			String newUrl = "http://download.ghzhushou.com/etag"
+					+ "?url=" + URLEncoder.encode(url, "utf-8")
+					+ "&" + System.currentTimeMillis();
+			HttpURLConnection connection = (HttpURLConnection) new URL(newUrl).openConnection();
+			connection.setRequestMethod("GET");
+			connection.setConnectTimeout(CONNECT_TIME);
+			connection.setReadTimeout(READ_TIME);
+			connection.setDoInput(true);
+			connection.connect();
+
+			int code = connection.getResponseCode();
+			if (code == 200) {
+				InputStream is = connection.getInputStream();
+				ByteArrayOutputStream baos = new ByteArrayOutputStream();
+				byte[] buffer = new byte[2048];
+				int len;
+				while ((len = is.read(buffer)) != -1) {
+					baos.write(buffer, 0, len);
+				}
+				baos.flush();
+				JSONObject response = new JSONObject(baos.toString("utf-8"));
+				return response.getString("etag");
+			}
+		} catch (IOException | JSONException e) {
+			e.printStackTrace();
+		}
+		return null;
+	}
+
 	public void setStatus(DownloadStatus status) {
 		this.status = status;
 	}