From 1f594ad311b8f72fb78f14d137dfb53f59b03f85 Mon Sep 17 00:00:00 2001
From: daniel oeh <daniel.oeh@gmail.com>
Date: Mon, 2 Sep 2013 15:13:00 +0200
Subject: [PATCH] Upload changes instead of whole subscription list

---
 AndroidManifest.xml                           |  3 +-
 res/layout/gpodnetauth_device.xml             | 26 ++---
 .../GpodnetAuthenticationActivity.java        | 23 ++++-
 .../antennapod/gpoddernet/GpodnetService.java | 55 ++++++++++-
 .../model/GpodnetUploadChangesResponse.java   | 56 +++++++++++
 .../preferences/GpodnetPreferences.java       | 99 ++++++++++++++++++-
 .../service/GpodnetSyncService.java           | 29 ++++--
 .../danoeh/antennapod/storage/DBWriter.java   | 26 ++++-
 .../antennapod/storage/PodDBAdapter.java      |  9 ++
 .../gpodnet/GPodnetServiceTest.java           | 12 +++
 10 files changed, 308 insertions(+), 30 deletions(-)
 create mode 100644 src/de/danoeh/antennapod/gpoddernet/model/GpodnetUploadChangesResponse.java

diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index fe16eb0e5..4e9752237 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -375,7 +375,8 @@
         <activity
             android:name=".activity.gpoddernet.GpodnetAuthenticationActivity"
             android:configChanges="orientation"
-            android:label="@string/gpodnet_auth_label">
+            android:label="@string/gpodnet_auth_label"
+            android:screenOrientation="portrait">
             <intent-filter>
                 <action android:name=".activity.gpoddernet.GpodnetAuthenticationActivity"/>
                 <category android:name="android.intent.category.DEFAULT"/>
diff --git a/res/layout/gpodnetauth_device.xml b/res/layout/gpodnetauth_device.xml
index 3f8d0716c..21f2ef295 100644
--- a/res/layout/gpodnetauth_device.xml
+++ b/res/layout/gpodnetauth_device.xml
@@ -25,20 +25,20 @@
         android:textColor="?android:attr/textColorSecondary"
         android:layout_margin="16dp"/>
 
-    <EditText
-        android:id="@+id/etxtDeviceID"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:hint="@string/gpodnetauth_device_deviceID"
-        android:layout_below="@id/txtvDescription"
-        android:layout_margin="8dp"/>
-
     <EditText
         android:id="@+id/etxtCaption"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:hint="@string/gpodnetauth_device_caption"
-        android:layout_below="@id/etxtDeviceID"
+        android:layout_below="@id/txtvDescription"
+        android:layout_margin="8dp"/>
+
+    <EditText
+        android:id="@+id/etxtDeviceID"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:hint="@string/gpodnetauth_device_deviceID"
+        android:layout_below="@id/etxtCaption"
         android:layout_margin="8dp"/>
 
     <Button
@@ -47,7 +47,7 @@
         android:layout_height="wrap_content"
         android:layout_margin="8dp"
         android:layout_alignParentRight="true"
-        android:layout_below="@id/etxtCaption"
+        android:layout_below="@id/etxtDeviceID"
         android:text="@string/gpodnetauth_device_butCreateNewDevice"/>
 
     <TextView
@@ -89,10 +89,10 @@
         android:id="@+id/butChooseExistingDevice"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:layout_below="@id/txtvChooseExistingDevice"
-        android:layout_alignParentRight="true"
         android:layout_margin="16dp"
-        android:text="@string/gpodnetauth_device_butChoose"/>
+        android:text="@string/gpodnetauth_device_butChoose"
+        android:layout_alignTop="@+id/spinnerChooseDevice"
+        android:layout_alignRight="@+id/txtvChooseExistingDevice"/>
 
     <Spinner
         android:id="@+id/spinnerChooseDevice"
diff --git a/src/de/danoeh/antennapod/activity/gpoddernet/GpodnetAuthenticationActivity.java b/src/de/danoeh/antennapod/activity/gpoddernet/GpodnetAuthenticationActivity.java
index 74695f38c..94f3d5527 100644
--- a/src/de/danoeh/antennapod/activity/gpoddernet/GpodnetAuthenticationActivity.java
+++ b/src/de/danoeh/antennapod/activity/gpoddernet/GpodnetAuthenticationActivity.java
@@ -2,6 +2,7 @@ package de.danoeh.antennapod.activity.gpoddernet;
 
 import android.content.Context;
 import android.content.Intent;
+import android.content.res.Configuration;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.support.v7.app.ActionBarActivity;
@@ -19,6 +20,7 @@ import de.danoeh.antennapod.preferences.GpodnetPreferences;
 import de.danoeh.antennapod.preferences.UserPreferences;
 import de.danoeh.antennapod.service.GpodnetSyncService;
 
+import java.security.SecureRandom;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
@@ -32,6 +34,8 @@ import java.util.concurrent.atomic.AtomicReference;
 public class GpodnetAuthenticationActivity extends ActionBarActivity {
     private static final String TAG = "GpodnetAuthenticationActivity";
 
+    private static final String CURRENT_STEP = "current_step";
+
     private ViewFlipper viewFlipper;
 
     private static final int STEP_DEFAULT = -1;
@@ -78,6 +82,10 @@ public class GpodnetAuthenticationActivity extends ActionBarActivity {
         }
     }
 
+    @Override
+    public void onConfigurationChanged(Configuration newConfig) {
+    }
+
     private void setupLoginView(View view) {
         final EditText username = (EditText) view.findViewById(R.id.etxtUsername);
         final EditText password = (EditText) view.findViewById(R.id.etxtPassword);
@@ -167,7 +175,7 @@ public class GpodnetAuthenticationActivity extends ActionBarActivity {
                 if (gpodnetDevices != null) {
                     List<String> deviceNames = new ArrayList<String>();
                     for (GpodnetDevice device : gpodnetDevices) {
-                        deviceNames.add(device.getId());
+                        deviceNames.add(device.getCaption());
                     }
                     spinnerDevices.setAdapter(new ArrayAdapter<String>(GpodnetAuthenticationActivity.this,
                             android.R.layout.simple_spinner_dropdown_item, deviceNames));
@@ -244,6 +252,7 @@ public class GpodnetAuthenticationActivity extends ActionBarActivity {
             }
         });
 
+        deviceID.setText(generateDeviceID());
         chooseDevice.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
@@ -254,6 +263,18 @@ public class GpodnetAuthenticationActivity extends ActionBarActivity {
         });
     }
 
+
+    private String generateDeviceID() {
+        final int DEVICE_ID_LENGTH = 10;
+        StringBuilder buffer = new StringBuilder(DEVICE_ID_LENGTH);
+        SecureRandom random = new SecureRandom();
+        for (int i = 0; i < DEVICE_ID_LENGTH; i++) {
+            buffer.append(random.nextInt(10));
+
+        }
+        return buffer.toString();
+    }
+
     private boolean checkDeviceIDText(EditText deviceID, TextView txtvError, List<GpodnetDevice> devices) {
         String text = deviceID.getText().toString();
         if (text.length() == 0) {
diff --git a/src/de/danoeh/antennapod/gpoddernet/GpodnetService.java b/src/de/danoeh/antennapod/gpoddernet/GpodnetService.java
index 11d7a8517..4c922d12b 100644
--- a/src/de/danoeh/antennapod/gpoddernet/GpodnetService.java
+++ b/src/de/danoeh/antennapod/gpoddernet/GpodnetService.java
@@ -1,10 +1,7 @@
 package de.danoeh.antennapod.gpoddernet;
 
 import de.danoeh.antennapod.AppConfig;
-import de.danoeh.antennapod.gpoddernet.model.GpodnetDevice;
-import de.danoeh.antennapod.gpoddernet.model.GpodnetPodcast;
-import de.danoeh.antennapod.gpoddernet.model.GpodnetSubscriptionChange;
-import de.danoeh.antennapod.gpoddernet.model.GpodnetTag;
+import de.danoeh.antennapod.gpoddernet.model.*;
 import org.apache.http.Header;
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpResponse;
@@ -30,6 +27,7 @@ import java.io.UnsupportedEncodingException;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -387,6 +385,55 @@ public class GpodnetService {
         }
     }
 
+    /**
+     * Updates the subscription list of a specific device.
+     * <p/>
+     * This method requires authentication.
+     *
+     * @param username The username. Must be the same user as the one which is
+     *                 currently logged in.
+     * @param deviceId The ID of the device whose subscriptions should be updated.
+     * @param added    Collection of feed URLs of added feeds. This Collection MUST NOT contain any duplicates
+     * @param removed  Collection of feed URLs of removed feeds. This Collection MUST NOT contain any duplicates
+     * @return a GpodnetUploadChangesResponse. See {@link de.danoeh.antennapod.gpoddernet.model.GpodnetUploadChangesResponse}
+     * for details.
+     * @throws java.lang.IllegalArgumentException                      if username, deviceId, added or removed is null.
+     * @throws de.danoeh.antennapod.gpoddernet.GpodnetServiceException if added or removed contain duplicates or if there
+     *                                                                 is an authentication error.
+     */
+    public GpodnetUploadChangesResponse uploadChanges(String username, String deviceId, Collection<String> added,
+                                                      Collection<String> removed) throws GpodnetServiceException {
+        if (username == null || deviceId == null || added == null || removed == null) {
+            throw new IllegalArgumentException(
+                    "Username, device ID, added and removed must not be null");
+        }
+        try {
+            URI uri = new URI(BASE_SCHEME, BASE_HOST, String.format(
+                    "/api/2/subscriptions/%s/%s.json", username, deviceId), null);
+
+            final JSONObject requestObject = new JSONObject();
+            requestObject.put("add", new JSONArray(added));
+            requestObject.put("remove", new JSONArray(removed));
+
+            HttpPost request = new HttpPost(uri);
+            StringEntity entity = new StringEntity(requestObject.toString(), "UTF-8");
+            request.setEntity(entity);
+
+            final String response = executeRequest(request);
+            return GpodnetUploadChangesResponse.fromJSONObject(response);
+        } catch (URISyntaxException e) {
+            e.printStackTrace();
+            throw new IllegalStateException(e);
+        } catch (JSONException e) {
+            e.printStackTrace();
+            throw new GpodnetServiceException(e);
+        } catch (UnsupportedEncodingException e) {
+            e.printStackTrace();
+            throw new IllegalStateException(e);
+        }
+
+    }
+
     /**
      * Returns all subscription changes of a specific device.
      * <p/>
diff --git a/src/de/danoeh/antennapod/gpoddernet/model/GpodnetUploadChangesResponse.java b/src/de/danoeh/antennapod/gpoddernet/model/GpodnetUploadChangesResponse.java
new file mode 100644
index 000000000..fee8c7d28
--- /dev/null
+++ b/src/de/danoeh/antennapod/gpoddernet/model/GpodnetUploadChangesResponse.java
@@ -0,0 +1,56 @@
+package de.danoeh.antennapod.gpoddernet.model;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Object returned by {@link de.danoeh.antennapod.gpoddernet.GpodnetService} in uploadChanges method.
+ */
+public class GpodnetUploadChangesResponse {
+
+    /**
+     * timestamp/ID that can be used for requesting changes since this upload.
+     */
+    public final long timestamp;
+
+    /**
+     * URLs that should be updated. The key of the map is the original URL, the value of the map
+     * is the sanitized URL.
+     */
+    public final Map<String, String> updatedUrls;
+
+    public GpodnetUploadChangesResponse(long timestamp, Map<String, String> updatedUrls) {
+        this.timestamp = timestamp;
+        this.updatedUrls = updatedUrls;
+    }
+
+    /**
+     * Creates a new GpodnetUploadChangesResponse-object from a JSON object that was
+     * returned by an uploadChanges call.
+     *
+     * @throws org.json.JSONException If the method could not parse the JSONObject.
+     */
+    public static GpodnetUploadChangesResponse fromJSONObject(String objectString) throws JSONException {
+        final JSONObject object = new JSONObject(objectString);
+        final long timestamp = object.getLong("timestamp");
+        Map<String, String> updatedUrls = new HashMap<String, String>();
+        JSONArray urls = object.getJSONArray("update_urls");
+        for (int i = 0; i < urls.length(); i++) {
+            JSONArray urlPair = urls.getJSONArray(i);
+            updatedUrls.put(urlPair.getString(0), urlPair.getString(1));
+        }
+        return new GpodnetUploadChangesResponse(timestamp, updatedUrls);
+    }
+
+    @Override
+    public String toString() {
+        return "GpodnetUploadChangesResponse{" +
+                "timestamp=" + timestamp +
+                ", updatedUrls=" + updatedUrls +
+                '}';
+    }
+}
diff --git a/src/de/danoeh/antennapod/preferences/GpodnetPreferences.java b/src/de/danoeh/antennapod/preferences/GpodnetPreferences.java
index 0a9984137..bb98fb998 100644
--- a/src/de/danoeh/antennapod/preferences/GpodnetPreferences.java
+++ b/src/de/danoeh/antennapod/preferences/GpodnetPreferences.java
@@ -3,6 +3,12 @@ package de.danoeh.antennapod.preferences;
 import android.content.Context;
 import android.content.SharedPreferences;
 import de.danoeh.antennapod.PodcastApp;
+import de.danoeh.antennapod.service.GpodnetSyncService;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * Manages preferences for accessing gpodder.net service
@@ -17,11 +23,17 @@ public class GpodnetPreferences {
     public static final String PREF_GPODNET_DEVICEID = "de.danoeh.antennapod.preferences.gpoddernet.deviceID";
 
     public static final String PREF_LAST_SYNC_TIMESTAMP = "de.danoeh.antennapod.preferences.gpoddernet.last_sync_timestamp";
+    public static final String PREF_SYNC_ADDED = "de.danoeh.antennapod.preferences.gpoddernet.sync_added";
+    public static final String PREF_SYNC_REMOVED = "de.danoeh.antennapod.preferences.gpoddernet.sync_removed";
 
     private static String username;
     private static String password;
     private static String deviceID;
 
+    private static ReentrantLock feedListLock = new ReentrantLock();
+    private static Set<String> addedFeeds;
+    private static Set<String> removedFeeds;
+
     /**
      * Last value returned by getSubscriptionChanges call. Will be used for all subsequent calls of getSubscriptionChanges.
      */
@@ -33,13 +45,16 @@ public class GpodnetPreferences {
         return PodcastApp.getInstance().getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
     }
 
-    private static void ensurePreferencesLoaded() {
+    private static synchronized void ensurePreferencesLoaded() {
         if (!preferencesLoaded) {
             SharedPreferences prefs = getPreferences();
             username = prefs.getString(PREF_GPODNET_USERNAME, null);
             password = prefs.getString(PREF_GPODNET_PASSWORD, null);
             deviceID = prefs.getString(PREF_GPODNET_DEVICEID, null);
             lastSyncTimestamp = prefs.getLong(PREF_LAST_SYNC_TIMESTAMP, 0);
+            addedFeeds = readListFromString(prefs.getString(PREF_SYNC_ADDED, ""));
+            removedFeeds = readListFromString(prefs.getString(PREF_SYNC_REMOVED, ""));
+
             preferencesLoaded = true;
         }
     }
@@ -56,6 +71,12 @@ public class GpodnetPreferences {
         editor.commit();
     }
 
+    private static void writePreference(String key, Collection<String> value) {
+        SharedPreferences.Editor editor = getPreferences().edit();
+        editor.putString(key, writeListToString(value));
+        editor.commit();
+    }
+
     public static String getUsername() {
         ensurePreferencesLoaded();
         return username;
@@ -96,6 +117,65 @@ public class GpodnetPreferences {
         writePreference(PREF_LAST_SYNC_TIMESTAMP, lastSyncTimestamp);
     }
 
+    public static void addAddedFeed(String feed) {
+        ensurePreferencesLoaded();
+        feedListLock.lock();
+        if (addedFeeds.add(feed)) {
+            writePreference(PREF_SYNC_ADDED, addedFeeds);
+        }
+        if (removedFeeds.remove(feed)) {
+            writePreference(PREF_SYNC_REMOVED, removedFeeds);
+        }
+        feedListLock.unlock();
+        GpodnetSyncService.sendActionUploadIntent(PodcastApp.getInstance());
+    }
+
+    public static void addRemovedFeed(String feed) {
+        ensurePreferencesLoaded();
+        feedListLock.lock();
+        if (removedFeeds.add(feed)) {
+            writePreference(PREF_SYNC_REMOVED, removedFeeds);
+        }
+        if (addedFeeds.remove(feed)) {
+            writePreference(PREF_SYNC_ADDED, addedFeeds);
+        }
+        feedListLock.unlock();
+        GpodnetSyncService.sendActionUploadIntent(PodcastApp.getInstance());
+    }
+
+    public static Set<String> getAddedFeedsCopy() {
+        ensurePreferencesLoaded();
+        Set<String> copy = new HashSet<String>();
+        feedListLock.lock();
+        copy.addAll(addedFeeds);
+        feedListLock.unlock();
+        return copy;
+    }
+
+    public static void removeAddedFeeds(Set<String> removed) {
+        ensurePreferencesLoaded();
+        feedListLock.lock();
+        addedFeeds.removeAll(removed);
+        writePreference(PREF_SYNC_ADDED, addedFeeds);
+        feedListLock.unlock();
+    }
+
+    public static Set<String> getRemovedFeedsCopy() {
+        ensurePreferencesLoaded();
+        Set<String> copy = new HashSet<String>();
+        feedListLock.lock();
+        copy.addAll(removedFeeds);
+        feedListLock.unlock();
+        return copy;
+    }
+
+    public static void removeRemovedFeeds(Set<String> removed) {
+        ensurePreferencesLoaded();
+        removedFeeds.removeAll(removed);
+        writePreference(PREF_SYNC_REMOVED, removedFeeds);
+
+    }
+
     /**
      * Returns true if device ID, username and password have a non-null value
      */
@@ -110,4 +190,21 @@ public class GpodnetPreferences {
         setDeviceID(null);
         setLastSyncTimestamp(0);
     }
+
+    private static Set<String> readListFromString(String s) {
+        Set<String> result = new HashSet<String>();
+        for (String item : s.split(" ")) {
+            result.add(item);
+        }
+        return result;
+    }
+
+    private static String writeListToString(Collection<String> c) {
+        StringBuilder result = new StringBuilder();
+        for (String item : c) {
+            result.append(item);
+            result.append(" ");
+        }
+        return result.toString().trim();
+    }
 }
diff --git a/src/de/danoeh/antennapod/service/GpodnetSyncService.java b/src/de/danoeh/antennapod/service/GpodnetSyncService.java
index 585b8919b..464b057a6 100644
--- a/src/de/danoeh/antennapod/service/GpodnetSyncService.java
+++ b/src/de/danoeh/antennapod/service/GpodnetSyncService.java
@@ -15,15 +15,15 @@ import de.danoeh.antennapod.gpoddernet.GpodnetService;
 import de.danoeh.antennapod.gpoddernet.GpodnetServiceAuthenticationException;
 import de.danoeh.antennapod.gpoddernet.GpodnetServiceException;
 import de.danoeh.antennapod.gpoddernet.model.GpodnetSubscriptionChange;
+import de.danoeh.antennapod.gpoddernet.model.GpodnetUploadChangesResponse;
 import de.danoeh.antennapod.preferences.GpodnetPreferences;
-import de.danoeh.antennapod.storage.DBReader;
-import de.danoeh.antennapod.storage.DBTasks;
-import de.danoeh.antennapod.storage.DownloadRequestException;
-import de.danoeh.antennapod.storage.DownloadRequester;
+import de.danoeh.antennapod.storage.*;
 import de.danoeh.antennapod.util.NetworkUtils;
 
 import java.util.Date;
 import java.util.List;
+import java.util.Set;
+import java.util.concurrent.ExecutionException;
 
 /**
  * Synchronizes local subscriptions with gpodder.net service. The service should be started with an ACTION_UPLOAD_CHANGES,
@@ -71,8 +71,8 @@ public class GpodnetSyncService extends Service {
             new Thread() {
                 @Override
                 public void run() {
-                    uploadChanges();
                     downloadChanges();
+                    uploadChanges();
                 }
             }.start();
         }
@@ -135,14 +135,27 @@ public class GpodnetSyncService extends Service {
             try {
                 if (AppConfig.DEBUG) Log.d(TAG, "Uploading subscription list");
                 GpodnetService service = tryLogin();
-                List<String> subscriptions = DBReader.getFeedListDownloadUrls(GpodnetSyncService.this);
 
-                if (AppConfig.DEBUG) Log.d(TAG, "Uploading subscriptions: " + subscriptions.toString());
+                Set<String> added = GpodnetPreferences.getAddedFeedsCopy();
+                Set<String> removed = GpodnetPreferences.getRemovedFeedsCopy();
 
-                service.uploadSubscriptions(GpodnetPreferences.getUsername(), GpodnetPreferences.getDeviceID(), subscriptions);
+                if (AppConfig.DEBUG) Log.d(TAG, String.format("Uploading subscriptions, Added: %s\nRemoved: %s",
+                        added.toString(), removed.toString()));
+
+                GpodnetUploadChangesResponse response = service.uploadChanges(GpodnetPreferences.getUsername(), GpodnetPreferences.getDeviceID(), added, removed);
+
+                if (AppConfig.DEBUG) Log.d(TAG, "Upload subscriptions response: " + response.toString());
+
+                GpodnetPreferences.removeAddedFeeds(added);
+                GpodnetPreferences.removeRemovedFeeds(removed);
+                DBWriter.updateFeedDownloadURLs(GpodnetSyncService.this, response.updatedUrls).get();
             } catch (GpodnetServiceException e) {
                 e.printStackTrace();
                 updateErrorNotification(e);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            } catch (ExecutionException e) {
+                e.printStackTrace();
             }
         }
         stopSelf();
diff --git a/src/de/danoeh/antennapod/storage/DBWriter.java b/src/de/danoeh/antennapod/storage/DBWriter.java
index bbc6f94b7..b3e1d6bc1 100644
--- a/src/de/danoeh/antennapod/storage/DBWriter.java
+++ b/src/de/danoeh/antennapod/storage/DBWriter.java
@@ -4,6 +4,7 @@ import java.io.File;
 import java.util.Date;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
@@ -17,6 +18,7 @@ import android.preference.PreferenceManager;
 import android.util.Log;
 import de.danoeh.antennapod.AppConfig;
 import de.danoeh.antennapod.feed.*;
+import de.danoeh.antennapod.preferences.GpodnetPreferences;
 import de.danoeh.antennapod.preferences.PlaybackPreferences;
 import de.danoeh.antennapod.service.GpodnetSyncService;
 import de.danoeh.antennapod.service.PlaybackService;
@@ -173,7 +175,7 @@ public class DBWriter {
                     adapter.removeFeed(feed);
                     adapter.close();
 
-                    GpodnetSyncService.sendActionUploadIntent(context);
+                    GpodnetPreferences.addRemovedFeed(feed.getDownload_url());
                     EventDistributor.getInstance().sendFeedUpdateBroadcast();
                 }
             }
@@ -617,7 +619,7 @@ public class DBWriter {
                 adapter.setCompleteFeed(feed);
                 adapter.close();
 
-                GpodnetSyncService.sendActionUploadIntent(context);
+                GpodnetPreferences.addAddedFeed(feed.getDownload_url());
                 EventDistributor.getInstance().sendFeedUpdateBroadcast();
             }
         });
@@ -720,6 +722,26 @@ public class DBWriter {
         });
     }
 
+    /**
+     * Updates download URLs of feeds from a given Map. The key of the Map is the original URL of the feed
+     * and the value is the updated URL
+     * */
+    public static Future<?> updateFeedDownloadURLs(final Context context, final Map<String, String> urls) {
+        return dbExec.submit(new Runnable() {
+            @Override
+            public void run() {
+                PodDBAdapter adapter = new PodDBAdapter(context);
+                adapter.open();
+                for (String key : urls.keySet()) {
+                    if (AppConfig.DEBUG) Log.d(TAG, "Replacing URL " + key + " with url " + urls.get(key));
+
+                    adapter.setFeedDownloadUrl(key, urls.get(key));
+                }
+                adapter.close();
+            }
+        });
+    }
+
     private static boolean itemListContains(List<FeedItem> items, long itemId) {
         for (FeedItem item : items) {
             if (item.getId() == itemId) {
diff --git a/src/de/danoeh/antennapod/storage/PodDBAdapter.java b/src/de/danoeh/antennapod/storage/PodDBAdapter.java
index ff98d4ae7..ce1bf721d 100644
--- a/src/de/danoeh/antennapod/storage/PodDBAdapter.java
+++ b/src/de/danoeh/antennapod/storage/PodDBAdapter.java
@@ -425,6 +425,15 @@ public class PodDBAdapter {
         db.endTransaction();
     }
 
+    /**
+     * Updates the download URL of a Feed.
+     */
+    public void setFeedDownloadUrl(String original, String updated) {
+        ContentValues values = new ContentValues();
+        values.put(KEY_DOWNLOAD_URL, updated);
+        db.update(TABLE_NAME_FEEDS, values, KEY_DOWNLOAD_URL + "=?", new String[]{original});
+    }
+
     public void setFeedItemlist(List<FeedItem> items) {
         db.beginTransaction();
         for (FeedItem item : items) {
diff --git a/src/instrumentationTest/de/test/antennapod/gpodnet/GPodnetServiceTest.java b/src/instrumentationTest/de/test/antennapod/gpodnet/GPodnetServiceTest.java
index bcf0d5d43..a96fc7aab 100644
--- a/src/instrumentationTest/de/test/antennapod/gpodnet/GPodnetServiceTest.java
+++ b/src/instrumentationTest/de/test/antennapod/gpodnet/GPodnetServiceTest.java
@@ -1,12 +1,14 @@
 package instrumentationTest.de.test.antennapod.gpodnet;
 
 import android.test.AndroidTestCase;
+import android.util.Log;
 import de.danoeh.antennapod.gpoddernet.GpodnetService;
 import de.danoeh.antennapod.gpoddernet.GpodnetServiceException;
 import de.danoeh.antennapod.gpoddernet.model.GpodnetDevice;
 import de.danoeh.antennapod.gpoddernet.model.GpodnetTag;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 /**
@@ -49,6 +51,16 @@ public class GPodnetServiceTest extends AndroidTestCase {
         service.uploadSubscriptions(USER, "radio", l);
     }
 
+    public void testUploadChanges() throws GpodnetServiceException {
+        authenticate();
+        String[] URLS = {"http://bitsundso.de/feed", "http://gamesundso.de/feed", "http://cre.fm/feed/mp3/", "http://freakshow.fm/feed/m4a/"};
+        List<String> subscriptions = Arrays.asList(URLS[0], URLS[1]);
+        List<String> removed = Arrays.asList(URLS[0]);
+        List<String> added = Arrays.asList(URLS[2], URLS[3]);
+        service.uploadSubscriptions(USER, "radio", subscriptions);
+        service.uploadChanges(USER, "radio", added, removed);
+    }
+
     public void testGetSubscriptionChanges() throws GpodnetServiceException {
         authenticate();
         service.getSubscriptionChanges(USER, "radio", 1362322610L);