Merge pull request #1633 from mfietz/improve_if_modified_since

Improve If-Modified-Since/ETag

9 files changed, 111 insertions, 65 deletions

diff --git a/core/src/main/java/de/danoeh/antennapod/core/backup/OpmlBackupAgent.java b/core/src/main/java/de/danoeh/antennapod/core/backup/OpmlBackupAgent.java
index 5ea0ba904..690fbdfc6 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/backup/OpmlBackupAgent.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/backup/OpmlBackupAgent.java
@@ -156,10 +156,9 @@ public class OpmlBackupAgent extends BackupAgentHelper {
                 ArrayList<OpmlElement> opmlElements = new OpmlReader().readDocument(reader);
                 mChecksum = digester == null ? null : digester.digest();
                 DownloadRequester downloader = DownloadRequester.getInstance();
-                Date lastUpdated = new Date();
 
                 for (OpmlElement opmlElem : opmlElements) {
-                    Feed feed = new Feed(opmlElem.getXmlUrl(), lastUpdated, opmlElem.getText());
+                    Feed feed = new Feed(opmlElem.getXmlUrl(), null, opmlElem.getText());
 
                     try {
                         downloader.downloadFeed(mContext, feed);
diff --git a/core/src/main/java/de/danoeh/antennapod/core/feed/Feed.java b/core/src/main/java/de/danoeh/antennapod/core/feed/Feed.java
index 4be788f33..d2d7cbc73 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/feed/Feed.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/feed/Feed.java
@@ -44,10 +44,12 @@ public class Feed extends FeedFile implements FlattrThing, ImageResource {
     private String author;
     private FeedImage image;
     private List<FeedItem> items;
+
     /**
-     * Date of last refresh.
+     * String that identifies the last update (adopted from Last-Modified or ETag header)
      */
-    private Date lastUpdate;
+    private String lastUpdate;
+
     private FlattrStatus flattrStatus;
     private String paymentLink;
     /**
@@ -91,18 +93,14 @@ public class Feed extends FeedFile implements FlattrThing, ImageResource {
     /**
      * This constructor is used for restoring a feed from the database.
      */
-    public Feed(long id, Date lastUpdate, String title, String link, String description, String paymentLink,
+    public Feed(long id, String lastUpdate, String title, String link, String description, String paymentLink,
                 String author, String language, String type, String feedIdentifier, FeedImage image, String fileUrl,
                 String downloadUrl, boolean downloaded, FlattrStatus status, boolean paged, String nextPageLink,
                 String filter, boolean lastUpdateFailed) {
         super(fileUrl, downloadUrl, downloaded);
         this.id = id;
         this.title = title;
-        if (lastUpdate != null) {
-            this.lastUpdate = (Date) lastUpdate.clone();
-        } else {
-            this.lastUpdate = null;
-        }
+        this.lastUpdate = lastUpdate;
         this.link = link;
         this.description = description;
         this.paymentLink = paymentLink;
@@ -126,7 +124,7 @@ public class Feed extends FeedFile implements FlattrThing, ImageResource {
     /**
      * This constructor is used for test purposes and uses a default flattr status object.
      */
-    public Feed(long id, Date lastUpdate, String title, String link, String description, String paymentLink,
+    public Feed(long id, String lastUpdate, String title, String link, String description, String paymentLink,
                 String author, String language, String type, String feedIdentifier, FeedImage image, String fileUrl,
                 String downloadUrl, boolean downloaded) {
         this(id, lastUpdate, title, link, description, paymentLink, author, language, type, feedIdentifier, image,
@@ -138,7 +136,6 @@ public class Feed extends FeedFile implements FlattrThing, ImageResource {
      */
     public Feed() {
         super();
-        lastUpdate = new Date();
         this.flattrStatus = new FlattrStatus();
     }
 
@@ -146,9 +143,9 @@ public class Feed extends FeedFile implements FlattrThing, ImageResource {
      * This constructor is used for requesting a feed download (it must not be used for anything else!). It should NOT be
      * used if the title of the feed is already known.
      */
-    public Feed(String url, Date lastUpdate) {
+    public Feed(String url, String lastUpdate) {
         super(null, url, false);
-        this.lastUpdate = (lastUpdate != null) ? (Date) lastUpdate.clone() : null;
+        this.lastUpdate = lastUpdate;
         this.flattrStatus = new FlattrStatus();
     }
 
@@ -156,7 +153,7 @@ public class Feed extends FeedFile implements FlattrThing, ImageResource {
      * This constructor is used for requesting a feed download (it must not be used for anything else!). It should be
      * used if the title of the feed is already known.
      */
-    public Feed(String url, Date lastUpdate, String title) {
+    public Feed(String url, String lastUpdate, String title) {
         this(url, lastUpdate);
         this.title = title;
         this.flattrStatus = new FlattrStatus();
@@ -166,7 +163,7 @@ public class Feed extends FeedFile implements FlattrThing, ImageResource {
      * This constructor is used for requesting a feed download (it must not be used for anything else!). It should be
      * used if the title of the feed is already known.
      */
-    public Feed(String url, Date lastUpdate, String title, String username, String password) {
+    public Feed(String url, String lastUpdate, String title, String username, String password) {
         this(url, lastUpdate, title);
         preferences = new FeedPreferences(0, true, FeedPreferences.AutoDeleteAction.GLOBAL, username, password);
     }
@@ -191,11 +188,9 @@ public class Feed extends FeedFile implements FlattrThing, ImageResource {
         int indexHide = cursor.getColumnIndex(PodDBAdapter.KEY_HIDE);
         int indexLastUpdateFailed = cursor.getColumnIndex(PodDBAdapter.KEY_LAST_UPDATE_FAILED);
 
-        Date lastUpdate = new Date(cursor.getLong(indexLastUpdate));
-
         Feed feed = new Feed(
                 cursor.getLong(indexId),
-                lastUpdate,
+                cursor.getString(indexLastUpdate),
                 cursor.getString(indexTitle),
                 cursor.getString(indexLink),
                 cursor.getString(indexDescription),
@@ -430,12 +425,12 @@ public class Feed extends FeedFile implements FlattrThing, ImageResource {
         this.items = list;
     }
 
-    public Date getLastUpdate() {
-        return (lastUpdate != null) ? (Date) lastUpdate.clone() : null;
+    public String getLastUpdate() {
+        return lastUpdate;
     }
 
-    public void setLastUpdate(Date lastUpdate) {
-        this.lastUpdate = (lastUpdate != null) ? (Date) lastUpdate.clone() : null;
+    public void setLastUpdate(String lastModified) {
+        this.lastUpdate = lastModified;
     }
 
     public String getFeedIdentifier() {
diff --git a/core/src/main/java/de/danoeh/antennapod/core/service/GpodnetSyncService.java b/core/src/main/java/de/danoeh/antennapod/core/service/GpodnetSyncService.java
index 0b90cef6c..e7ebff154 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/service/GpodnetSyncService.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/service/GpodnetSyncService.java
@@ -175,7 +175,7 @@ public class GpodnetSyncService extends Service {
         for (String downloadUrl : changes.getAdded()) {
             if (false == localSubscriptions.contains(downloadUrl) &&
                     false == localRemoved.contains(downloadUrl)) {
-                Feed feed = new Feed(downloadUrl, new Date(0));
+                Feed feed = new Feed(downloadUrl, null);
                 DownloadRequester.getInstance().downloadFeed(this, feed);
             }
         }
diff --git a/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadRequest.java b/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadRequest.java
index bc3006eea..7f40ea6e2 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadRequest.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadRequest.java
@@ -4,6 +4,7 @@ import android.os.Bundle;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 
 import de.danoeh.antennapod.core.feed.FeedFile;
 import de.danoeh.antennapod.core.util.URLChecker;
@@ -15,7 +16,7 @@ public class DownloadRequest implements Parcelable {
     private final String title;
     private String username;
     private String password;
-    private long ifModifiedSince;
+    private String lastModified;
     private boolean deleteOnFailure;
     private final long feedfileId;
     private final int feedfileType;
@@ -60,7 +61,7 @@ public class DownloadRequest implements Parcelable {
         this.feedfileType = builder.feedfileType;
         this.username = builder.username;
         this.password = builder.password;
-        this.ifModifiedSince = builder.ifModifiedSince;
+        this.lastModified = builder.lastModified;
         this.deleteOnFailure = builder.deleteOnFailure;
         this.arguments = (builder.arguments != null) ? builder.arguments : new Bundle();
     }
@@ -71,7 +72,7 @@ public class DownloadRequest implements Parcelable {
         title = in.readString();
         feedfileId = in.readLong();
         feedfileType = in.readInt();
-        ifModifiedSince = in.readLong();
+        lastModified = in.readString();
         deleteOnFailure = (in.readByte() > 0);
         arguments = in.readBundle();
         if (in.dataAvail() > 0) {
@@ -98,7 +99,7 @@ public class DownloadRequest implements Parcelable {
         dest.writeString(title);
         dest.writeLong(feedfileId);
         dest.writeInt(feedfileType);
-        dest.writeLong(ifModifiedSince);
+        dest.writeString(lastModified);
         dest.writeByte((deleteOnFailure) ? (byte) 1 : 0);
         dest.writeBundle(arguments);
         if (username != null) {
@@ -127,7 +128,7 @@ public class DownloadRequest implements Parcelable {
 
         DownloadRequest that = (DownloadRequest) o;
 
-        if (ifModifiedSince != that.ifModifiedSince) return false;
+        if (lastModified != that.lastModified) return false;
         if (deleteOnFailure != that.deleteOnFailure) return false;
         if (feedfileId != that.feedfileId) return false;
         if (feedfileType != that.feedfileType) return false;
@@ -143,7 +144,6 @@ public class DownloadRequest implements Parcelable {
         if (title != null ? !title.equals(that.title) : that.title != null) return false;
         if (username != null ? !username.equals(that.username) : that.username != null)
             return false;
-
         return true;
     }
 
@@ -154,7 +154,7 @@ public class DownloadRequest implements Parcelable {
         result = 31 * result + (title != null ? title.hashCode() : 0);
         result = 31 * result + (username != null ? username.hashCode() : 0);
         result = 31 * result + (password != null ? password.hashCode() : 0);
-        result = 31 * result + (int)ifModifiedSince;
+        result = 31 * result + (lastModified != null ? lastModified.hashCode() : 0);
         result = 31 * result + (deleteOnFailure ? 1 : 0);
         result = 31 * result + (int) (feedfileId ^ (feedfileId >>> 32));
         result = 31 * result + feedfileType;
@@ -234,13 +234,14 @@ public class DownloadRequest implements Parcelable {
         this.password = password;
     }
 
-    public DownloadRequest setIfModifiedSince(long time) {
-        this.ifModifiedSince = time;
+    public DownloadRequest setLastModified(@Nullable String lastModified) {
+        this.lastModified = lastModified;
         return this;
     }
 
-    public long getIfModifiedSince() {
-        return this.ifModifiedSince;
+    @Nullable
+    public String getLastModified() {
+        return lastModified;
     }
 
     public boolean isDeleteOnFailure() {
@@ -257,7 +258,7 @@ public class DownloadRequest implements Parcelable {
         private String title;
         private String username;
         private String password;
-        private long ifModifiedSince;
+        private String lastModified;
         private boolean deleteOnFailure = false;
         private long feedfileId;
         private int feedfileType;
@@ -276,8 +277,8 @@ public class DownloadRequest implements Parcelable {
             return this;
         }
 
-        public Builder ifModifiedSince(long time) {
-            this.ifModifiedSince = time;
+        public Builder lastModified(String lastModified) {
+            this.lastModified = lastModified;
             return this;
         }
 
diff --git a/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadService.java b/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadService.java
index d69228ceb..72fa1e1f8 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadService.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadService.java
@@ -824,7 +824,7 @@ public class DownloadService extends Service {
         }
 
         private Pair<DownloadRequest, FeedHandlerResult> parseFeed(DownloadRequest request) {
-            Feed feed = new Feed(request.getSource(), new Date());
+            Feed feed = new Feed(request.getSource(), request.getLastModified());
             feed.setFile_url(request.getDestination());
             feed.setId(request.getFeedfileId());
             feed.setDownloaded(true);
diff --git a/core/src/main/java/de/danoeh/antennapod/core/service/download/HttpDownloader.java b/core/src/main/java/de/danoeh/antennapod/core/service/download/HttpDownloader.java
index 0b9fba6f7..e3a195253 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/service/download/HttpDownloader.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/service/download/HttpDownloader.java
@@ -8,7 +8,6 @@ import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.Request;
 import com.squareup.okhttp.Response;
 import com.squareup.okhttp.ResponseBody;
-import com.squareup.okhttp.internal.http.HttpDate;
 
 import org.apache.commons.io.IOUtils;
 
@@ -28,6 +27,7 @@ import java.util.Date;
 import de.danoeh.antennapod.core.ClientConfig;
 import de.danoeh.antennapod.core.R;
 import de.danoeh.antennapod.core.feed.FeedImage;
+import de.danoeh.antennapod.core.util.DateUtils;
 import de.danoeh.antennapod.core.util.DownloadError;
 import de.danoeh.antennapod.core.util.StorageUtils;
 import de.danoeh.antennapod.core.util.URIUtil;
@@ -67,13 +67,19 @@ public class HttpDownloader extends Downloader {
             final URI uri = URIUtil.getURIFromRequestUrl(request.getSource());
             Request.Builder httpReq = new Request.Builder().url(uri.toURL())
                     .header("User-Agent", ClientConfig.USER_AGENT);
-            if(request.getIfModifiedSince() > 0) {
-                long threeDaysAgo = System.currentTimeMillis() - 1000*60*60*24*3;
-                if(request.getIfModifiedSince() > threeDaysAgo) {
-                    Date date = new Date(request.getIfModifiedSince());
-                    String httpDate = HttpDate.format(date);
-                    Log.d(TAG, "addHeader(\"If-Modified-Since\", \"" + httpDate + "\")");
-                    httpReq.addHeader("If-Modified-Since", httpDate);
+            if(!TextUtils.isEmpty(request.getLastModified())) {
+                String lastModified = request.getLastModified();
+                Date lastModifiedDate = DateUtils.parse(lastModified);
+                if(lastModifiedDate != null) {
+                    long threeDaysAgo = System.currentTimeMillis() - 1000 * 60 * 60 * 24 * 3;
+                    if (lastModifiedDate.getTime() > threeDaysAgo) {
+                        Log.d(TAG, "addHeader(\"If-Modified-Since\", \"" + lastModified + "\")");
+                        httpReq.addHeader("If-Modified-Since", lastModified);
+                    }
+                } else {
+                    String eTag = lastModified;
+                    Log.d(TAG, "addHeader(\"If-None-Match\", \"" + eTag + "\")");
+                    httpReq.addHeader("If-None-Match", eTag);
                 }
             }
 
@@ -235,6 +241,12 @@ public class HttpDownloader extends Downloader {
                     onFail(DownloadError.ERROR_IO_ERROR, "Download completed, but nothing was read");
                     return;
                 }
+                String lastModified = response.header("Last-Modified");
+                if(lastModified != null) {
+                    request.setLastModified(lastModified);
+                } else {
+                    request.setLastModified(response.header("ETag"));
+                }
                 onSuccess();
             }
 
diff --git a/core/src/main/java/de/danoeh/antennapod/core/storage/DBTasks.java b/core/src/main/java/de/danoeh/antennapod/core/storage/DBTasks.java
index efc60bfc2..ed593bb82 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/storage/DBTasks.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/storage/DBTasks.java
@@ -224,7 +224,28 @@ public final class DBTasks {
      */
     public static void refreshCompleteFeed(final Context context, final Feed feed) {
         try {
-            refreshFeed(context, feed, true);
+            refreshFeed(context, feed, true, false);
+        } catch (DownloadRequestException e) {
+            e.printStackTrace();
+            DBWriter.addDownloadStatus(
+                    new DownloadStatus(feed, feed
+                            .getHumanReadableIdentifier(),
+                            DownloadError.ERROR_REQUEST_ERROR, false, e
+                            .getMessage()
+                    )
+            );
+        }
+    }
+
+    /**
+     * Downloads all pages of the given feed even if feed has not been modified since last refresh
+     *
+     * @param context Used for requesting the download.
+     * @param feed    The Feed object.
+     */
+    public static void forceRefreshCompleteFeed(final Context context, final Feed feed) {
+        try {
+            refreshFeed(context, feed, true, true);
         } catch (DownloadRequestException e) {
             e.printStackTrace();
             DBWriter.addDownloadStatus(
@@ -248,11 +269,11 @@ public final class DBTasks {
     public static void loadNextPageOfFeed(final Context context, Feed feed, boolean loadAllPages) throws DownloadRequestException {
         if (feed.isPaged() && feed.getNextPageLink() != null) {
             int pageNr = feed.getPageNr() + 1;
-            Feed nextFeed = new Feed(feed.getNextPageLink(), new Date(), feed.getTitle() + "(" + pageNr + ")");
+            Feed nextFeed = new Feed(feed.getNextPageLink(), null, feed.getTitle() + "(" + pageNr + ")");
             nextFeed.setPageNr(pageNr);
             nextFeed.setPaged(true);
             nextFeed.setId(feed.getId());
-            DownloadRequester.getInstance().downloadFeed(context, nextFeed, loadAllPages);
+            DownloadRequester.getInstance().downloadFeed(context, nextFeed, loadAllPages, false);
         } else {
             Log.e(TAG, "loadNextPageOfFeed: Feed was either not paged or contained no nextPageLink");
         }
@@ -268,12 +289,25 @@ public final class DBTasks {
     public static void refreshFeed(Context context, Feed feed)
             throws DownloadRequestException {
         Log.d(TAG, "refreshFeed(feed.id: " + feed.getId() +")");
-        refreshFeed(context, feed, false);
+        refreshFeed(context, feed, false, false);
+    }
+
+    /**
+     * Refresh a specific feed even if feed has not been modified since last refresh
+     *
+     * @param context Used for requesting the download.
+     * @param feed    The Feed object.
+     */
+    public static void forceRefreshFeed(Context context, Feed feed)
+            throws DownloadRequestException {
+        Log.d(TAG, "refreshFeed(feed.id: " + feed.getId() +")");
+        refreshFeed(context, feed, false, true);
     }
 
-    private static void refreshFeed(Context context, Feed feed, boolean loadAllPages) throws DownloadRequestException {
+    private static void refreshFeed(Context context, Feed feed, boolean loadAllPages, boolean force)
+            throws DownloadRequestException {
         Feed f;
-        Date lastUpdate = feed.hasLastUpdateFailed() ? new Date(0) : feed.getLastUpdate();
+        String lastUpdate = feed.hasLastUpdateFailed() ? null : feed.getLastUpdate();
         if (feed.getPreferences() == null) {
             f = new Feed(feed.getDownload_url(), lastUpdate, feed.getTitle());
         } else {
@@ -281,7 +315,7 @@ public final class DBTasks {
                     feed.getPreferences().getUsername(), feed.getPreferences().getPassword());
         }
         f.setId(feed.getId());
-        DownloadRequester.getInstance().downloadFeed(context, f, loadAllPages);
+        DownloadRequester.getInstance().downloadFeed(context, f, loadAllPages, force);
     }
 
     /**
diff --git a/core/src/main/java/de/danoeh/antennapod/core/storage/DownloadRequester.java b/core/src/main/java/de/danoeh/antennapod/core/storage/DownloadRequester.java
index 0dc1dadeb..22c9538ca 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/storage/DownloadRequester.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/storage/DownloadRequester.java
@@ -88,7 +88,7 @@ public class DownloadRequester {
 
     private void download(Context context, FeedFile item, FeedFile container, File dest,
                           boolean overwriteIfExists, String username, String password,
-                          long ifModifiedSince, boolean deleteOnFailure, Bundle arguments) {
+                          String lastModified, boolean deleteOnFailure, Bundle arguments) {
         final boolean partiallyDownloadedFileExists = item.getFile_url() != null;
         if (isDownloadingFile(item)) {
                 Log.e(TAG, "URL " + item.getDownload_url()
@@ -129,7 +129,7 @@ public class DownloadRequester {
 
         DownloadRequest.Builder builder = new DownloadRequest.Builder(dest.toString(), item)
                 .withAuthentication(username, password)
-                .ifModifiedSince(ifModifiedSince)
+                .lastModified(lastModified)
                 .deleteOnFailure(deleteOnFailure)
                 .withArguments(arguments);
         DownloadRequest request = builder.build();
@@ -162,24 +162,25 @@ public class DownloadRequester {
      * @param feed Feed to download
      * @param loadAllPages Set to true to download all pages
      */
-    public synchronized void downloadFeed(Context context, Feed feed, boolean loadAllPages)
+    public synchronized void downloadFeed(Context context, Feed feed, boolean loadAllPages,
+                                          boolean force)
             throws DownloadRequestException {
         if (feedFileValid(feed)) {
             String username = (feed.getPreferences() != null) ? feed.getPreferences().getUsername() : null;
             String password = (feed.getPreferences() != null) ? feed.getPreferences().getPassword() : null;
-            long ifModifiedSince = feed.isPaged() ? 0 : feed.getLastUpdate().getTime();
+            String lastModified = feed.isPaged() || force ? null : feed.getLastUpdate();
 
             Bundle args = new Bundle();
             args.putInt(REQUEST_ARG_PAGE_NR, feed.getPageNr());
             args.putBoolean(REQUEST_ARG_LOAD_ALL_PAGES, loadAllPages);
 
             download(context, feed, null, new File(getFeedfilePath(context),
-                    getFeedfileName(feed)), true, username, password, ifModifiedSince, true, args);
+                    getFeedfileName(feed)), true, username, password, lastModified, true, args);
         }
     }
 
     public synchronized void downloadFeed(Context context, Feed feed) throws DownloadRequestException {
-        downloadFeed(context, feed, false);
+        downloadFeed(context, feed, false, false);
     }
 
     public synchronized void downloadMedia(Context context, FeedMedia feedmedia)
@@ -204,7 +205,7 @@ public class DownloadRequester {
                         getMediafilename(feedmedia));
             }
             download(context, feedmedia, feed,
-                    dest, false, username, password, 0, false, null);
+                    dest, false, username, password, null, false, null);
         }
     }
 
diff --git a/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java b/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java
index 85ff8fc8c..5b7f5f720 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java
@@ -368,7 +368,7 @@ public class PodDBAdapter {
         values.put(KEY_FILE_URL, feed.getFile_url());
         values.put(KEY_DOWNLOAD_URL, feed.getDownload_url());
         values.put(KEY_DOWNLOADED, feed.isDownloaded());
-        values.put(KEY_LASTUPDATE, feed.getLastUpdate().getTime());
+        values.put(KEY_LASTUPDATE, feed.getLastUpdate());
         values.put(KEY_TYPE, feed.getType());
         values.put(KEY_FEED_IDENTIFIER, feed.getFeedIdentifier());
 
@@ -1151,7 +1151,7 @@ public class PodDBAdapter {
      * The returned cursor uses the FEEDITEM_SEL_FI_SMALL selection.
      */
     public final Cursor getNewItemsCursor() {
-        String[] args = new String[] {
+        Object[] args = new String[] {
                 SEL_FI_SMALL_STR,
                 TABLE_NAME_FEED_ITEMS,
                 TABLE_NAME_FEEDS,
@@ -1512,7 +1512,7 @@ public class PodDBAdapter {
      */
     private static class PodDBHelper extends SQLiteOpenHelper {
 
-        private final static int VERSION = 1050003;
+        private final static int VERSION = 1050004;
 
         private Context context;
 
@@ -1756,7 +1756,6 @@ public class PodDBAdapter {
                 db.execSQL(PodDBAdapter.CREATE_INDEX_FEEDITEMS_PUBDATE);
                 db.execSQL(PodDBAdapter.CREATE_INDEX_FEEDITEMS_READ);
             }
-
             if (oldVersion < 1050003) {
                 // Migrates feed list filter data
 
@@ -1804,6 +1803,11 @@ public class PodDBAdapter {
                 db.execSQL("ALTER TABLE " + PodDBAdapter.TABLE_NAME_FEEDS
                         + " ADD COLUMN " + PodDBAdapter.KEY_KEEP_UPDATED + " INTEGER DEFAULT 1");
             }
+            if (oldVersion < 1050004) {
+                // prevent old timestamps to be misinterpreted as ETags
+                db.execSQL("UPDATE " + PodDBAdapter.TABLE_NAME_FEEDS
+                        +" SET " + PodDBAdapter.KEY_LASTUPDATE + "=NULL");
+            }
 
             EventBus.getDefault().post(ProgressEvent.end());
         }