More forgiving duplicate detection

app/src/androidTest/java/de/test/antennapod/util/URLCheckerTest.java

@@ -5,6 +5,8 @@ import de.danoeh.antennapod.core.util.URLChecker;
 import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 /**
  * Test class for URLChecker
@@ -119,4 +121,30 @@ public class URLCheckerTest {
         final String out = URLChecker.prepareURL(in, null);
         assertEquals("http://example.com", out);
     }
+
+    @Test
+    public void testUrlEqualsSame() {
+        assertTrue(URLChecker.urlEquals("https://www.example.com/test", "https://www.example.com/test"));
+        assertTrue(URLChecker.urlEquals("https://www.example.com/test", "https://www.example.com/test/"));
+        assertTrue(URLChecker.urlEquals("https://www.example.com/test", "https://www.example.com//test"));
+        assertTrue(URLChecker.urlEquals("https://www.example.com", "https://www.example.com/"));
+        assertTrue(URLChecker.urlEquals("https://www.example.com", "http://www.example.com"));
+        assertTrue(URLChecker.urlEquals("http://www.example.com/", "https://www.example.com/"));
+        assertTrue(URLChecker.urlEquals("https://www.example.com/?id=42", "https://www.example.com/?id=42"));
+        assertTrue(URLChecker.urlEquals("https://example.com/podcast%20test", "https://example.com/podcast test"));
+        assertTrue(URLChecker.urlEquals("https://example.com/?a=podcast%20test", "https://example.com/?a=podcast test"));
+        assertTrue(URLChecker.urlEquals("https://example.com/?", "https://example.com/"));
+        assertTrue(URLChecker.urlEquals("https://example.com/?", "https://example.com"));
+        assertTrue(URLChecker.urlEquals("https://Example.com", "https://example.com"));
+        assertTrue(URLChecker.urlEquals("https://example.com/test", "https://example.com/Test"));
+    }
+
+    @Test
+    public void testUrlEqualsDifferent() {
+        assertFalse(URLChecker.urlEquals("https://www.example.com/test", "https://www.example2.com/test"));
+        assertFalse(URLChecker.urlEquals("https://www.example.com/test", "https://www.example.de/test"));
+        assertFalse(URLChecker.urlEquals("https://example.com/", "https://otherpodcast.example.com/"));
+        assertFalse(URLChecker.urlEquals("https://www.example.com/?id=42&a=b", "https://www.example.com/?id=43&a=b"));
+        assertFalse(URLChecker.urlEquals("https://example.com/podcast%25test", "https://example.com/podcast test"));
+    }
 }

core/src/main/java/de/danoeh/antennapod/core/service/GpodnetSyncService.java

@@ -38,6 +38,7 @@ import de.danoeh.antennapod.core.storage.DBWriter;
 import de.danoeh.antennapod.core.storage.DownloadRequestException;
 import de.danoeh.antennapod.core.storage.DownloadRequester;
 import de.danoeh.antennapod.core.util.NetworkUtils;
+import de.danoeh.antennapod.core.util.URLChecker;
 import de.danoeh.antennapod.core.util.gui.NotificationUtils;
 
 /**
@@ -185,15 +186,14 @@ public class GpodnetSyncService extends SafeJobIntentService {
         // local changes are always superior to remote changes!
         // add subscription if (1) not already subscribed and (2) not just unsubscribed
         for (String downloadUrl : changes.getAdded()) {
-            if (!localSubscriptions.contains(downloadUrl) &&
+            if (!URLChecker.containsUrl(localSubscriptions, downloadUrl) && !localRemoved.contains(downloadUrl)) {
-                    !localRemoved.contains(downloadUrl)) {
                 Feed feed = new Feed(downloadUrl, null);
                 DownloadRequester.getInstance().downloadFeed(this, feed);
             }
         }
         // remove subscription if not just subscribed (again)
         for (String downloadUrl : changes.getRemoved()) {
-            if(!localAdded.contains(downloadUrl)) {
+            if (!localAdded.contains(downloadUrl)) {
                 DBTasks.removeFeedWithDownloadUrl(GpodnetSyncService.this, downloadUrl);
             }
         }

core/src/main/java/de/danoeh/antennapod/core/util/URLChecker.java

@@ -1,10 +1,16 @@
 package de.danoeh.antennapod.core.util;
 
 import android.net.Uri;
+import android.text.TextUtils;
 import androidx.annotation.NonNull;
 import android.util.Log;
 
 import de.danoeh.antennapod.core.BuildConfig;
+import okhttp3.HttpUrl;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 
 /**
  * Provides methods for checking and editing a URL.
@@ -78,4 +84,45 @@ public final class URLChecker {
             return prepareURL(url);
         }
     }
+
+    public static boolean containsUrl(List<String> list, String url) {
+        for (String item : list) {
+            if (urlEquals(item, url)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public static boolean urlEquals(String string1, String string2) {
+        HttpUrl url1 = HttpUrl.parse(string1);
+        HttpUrl url2 = HttpUrl.parse(string2);
+        if (!url1.host().equals(url2.host())) {
+            return false;
+        }
+        List<String> pathSegments1 = normalizePathSegments(url1.pathSegments());
+        List<String> pathSegments2 = normalizePathSegments(url2.pathSegments());
+        if (!pathSegments1.equals(pathSegments2)) {
+            return false;
+        }
+        if (TextUtils.isEmpty(url1.query())) {
+            return TextUtils.isEmpty(url2.query());
+        }
+        return url1.query().equals(url2.query());
+    }
+
+    /**
+     * Removes empty segments and converts all to lower case.
+     * @param input List of path segments
+     * @return Normalized list of path segments
+     */
+    private static List<String> normalizePathSegments(List<String> input) {
+        List<String> result = new ArrayList<>();
+        for (String string : input) {
+            if (!TextUtils.isEmpty(string)) {
+                result.add(string.toLowerCase());
+            }
+        }
+        return result;
+    }
 }