Image EXIF/XMP metadata removal routine

app/src/main/java/fr/free/nrw/commons/settings/Prefs.java

@@ -7,6 +7,7 @@ public class Prefs {
     public static final String DEFAULT_LICENSE = "defaultLicense";
     public static final String UPLOADS_SHOWING = "uploadsshowing";
     public static final String IS_CONTRIBUTION_COUNT_CHANGED = "ccontributionCountChanged";
+    public static final String MANAGED_EXIF_TAGS = "managedExifTags";
 
     public static class Licenses {
         public static final String CC_BY_SA_3 = "CC BY-SA 3.0";

app/src/main/java/fr/free/nrw/commons/settings/SettingsFragment.java

@@ -4,6 +4,7 @@
 import android.net.Uri;
 import android.os.Bundle;
 import android.preference.EditTextPreference;
+import android.preference.MultiSelectListPreference;
 import android.preference.Preference;
 import android.preference.PreferenceFragment;
 import android.preference.SwitchPreference;
@@ -14,6 +15,11 @@
 import com.karumi.dexter.listener.PermissionGrantedResponse;
 import com.karumi.dexter.listener.single.BasePermissionListener;
 
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
 import javax.inject.Inject;
 import javax.inject.Named;
 
@@ -59,6 +65,14 @@ public void onCreate(Bundle savedInstanceState) {
             return true;
         });
 
+        MultiSelectListPreference multiSelectListPref = (MultiSelectListPreference) findPreference("manageExifTags");
+        if (multiSelectListPref != null) {
+            multiSelectListPref.setOnPreferenceChangeListener((preference, newValue) -> {
+                defaultKvStore.putJson(Prefs.MANAGED_EXIF_TAGS, newValue);
+                return true;
+            });
+        }
+
         final EditTextPreference uploadLimit = (EditTextPreference) findPreference("uploads");
         int currentUploadLimit = defaultKvStore.getInt(Prefs.UPLOADS_SHOWING, 100);
         uploadLimit.setText(Integer.toString(currentUploadLimit));

app/src/main/java/fr/free/nrw/commons/ui/LongTitlePreferences/LongTitleMultiSelectListPreference.java

@@ -0,0 +1,38 @@
+package fr.free.nrw.commons.ui.LongTitlePreferences;
+
+import android.content.Context;
+import android.preference.MultiSelectListPreference;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.TextView;
+
+public class LongTitleMultiSelectListPreference extends MultiSelectListPreference {
+    /*
+    public LongTitleMultiSelectListPreference(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
+        super(context, attrs, defStyleAttr, defStyleRes);
+    }
+
+    public LongTitleMultiSelectListPreference(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+    */
+    public LongTitleMultiSelectListPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public LongTitleMultiSelectListPreference(Context context) {
+        super(context);
+    }
+
+    @Override
+    protected void onBindView(View view)
+    {
+        super.onBindView(view);
+
+        TextView title= view.findViewById(android.R.id.title);
+        if (title != null) {
+            title.setSingleLine(false);
+        }
+    }
+
+}

app/src/main/java/fr/free/nrw/commons/upload/FileMetadataUtils.java

@@ -0,0 +1,43 @@
+package fr.free.nrw.commons.upload;
+
+import timber.log.Timber;
+
+import static androidx.exifinterface.media.ExifInterface.*;
+
+/**
+ * Support utils for EXIF metadata handling
+ *
+ */
+public class FileMetadataUtils {
+
+    /**
+     * Takes EXIF label from sharedPreferences as input and returns relevant EXIF tags
+     *
+     * @param pref EXIF sharedPreference label
+     * @return EXIF tags
+     */
+    public static String[] getTagsFromPref(String pref) {
+        Timber.d("Retuning tags for pref:%s", pref);
+        switch (pref) {
+            case "Author":
+                return new String[]{TAG_ARTIST, TAG_CAMARA_OWNER_NAME};
+            case "Copyright":
+                return new String[]{TAG_COPYRIGHT};
+            case "Location":
+                return new String[]{TAG_GPS_LATITUDE, TAG_GPS_LATITUDE_REF,
+                        TAG_GPS_LONGITUDE, TAG_GPS_LONGITUDE_REF,
+                        TAG_GPS_ALTITUDE, TAG_GPS_ALTITUDE_REF};
+            case "Camera Model":
+                return new String[]{TAG_MAKE, TAG_MODEL};
+            case "Lens Model":
+                return new String[]{TAG_LENS_MAKE, TAG_LENS_MODEL, TAG_LENS_SPECIFICATION};
+            case "Serial Numbers":
+                return new String[]{TAG_BODY_SERIAL_NUMBER, TAG_LENS_SERIAL_NUMBER};
+            case "Software":
+                return new String[]{TAG_SOFTWARE};
+            default:
+                return new String[]{};
+        }
+    }
+
+}

app/src/main/java/fr/free/nrw/commons/upload/FileProcessor.java

@@ -2,22 +2,34 @@
 
 import android.annotation.SuppressLint;
 import android.content.ContentResolver;
+import android.content.Context;
 import android.net.Uri;
 import androidx.annotation.NonNull;
 
 import java.io.File;
 import java.io.IOException;
+import java.lang.reflect.Type;
+import java.util.Arrays;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 import javax.inject.Inject;
 import javax.inject.Named;
 import javax.inject.Singleton;
 
 import androidx.exifinterface.media.ExifInterface;
+
+import com.google.gson.reflect.TypeToken;
+
+import fr.free.nrw.commons.R;
 import fr.free.nrw.commons.caching.CacheController;
 import fr.free.nrw.commons.kvstore.JsonKvStore;
 import fr.free.nrw.commons.mwapi.CategoryApi;
+import fr.free.nrw.commons.settings.Prefs;
+import io.reactivex.Observable;
 import io.reactivex.disposables.CompositeDisposable;
+import io.reactivex.disposables.Disposable;
 import io.reactivex.schedulers.Schedulers;
 import timber.log.Timber;
 
@@ -66,7 +78,10 @@ void initFileDetails(@NonNull String filePath, ContentResolver contentResolver)
     /**
      * Processes filePath coordinates, either from EXIF data or user location
      */
-    GPSExtractor processFileCoordinates(SimilarImageInterface similarImageInterface) {
+    GPSExtractor processFileCoordinates(SimilarImageInterface similarImageInterface, Context context) {
+        // Redact EXIF data as indicated in preferences.
+        redactExifTags(exifInterface, getExifTagsToRedact(context));
+
         Timber.d("Calling GPSExtractor");
         imageObj = new GPSExtractor(exifInterface);
         decimalCoords = imageObj.getCoords();
@@ -81,6 +96,55 @@ GPSExtractor processFileCoordinates(SimilarImageInterface similarImageInterface)
         return imageObj;
     }
 
+    /**
+     * Gets EXIF Tags from preferences to be redacted.
+     *
+     * @param context application context
+     * @return        tags to be redacted
+     */
+    private Set<String> getExifTagsToRedact(Context context) {
+        Type setType = new TypeToken<Set<String>>() {}.getType();
+        Set<String> prefManageEXIFTags = defaultKvStore.getJson(Prefs.MANAGED_EXIF_TAGS, setType);
+
+        Set<String> redactTags = new HashSet<>(Arrays.asList(
+                context.getResources().getStringArray(R.array.pref_exifTag_values)));
+        Timber.d(redactTags.toString());
+
+        if (prefManageEXIFTags != null) redactTags.removeAll(prefManageEXIFTags);
+
+        return redactTags;
+    }
+
+    /**
+     * Redacts EXIF metadata as indicated in preferences.
+     *
+     * @param exifInterface  ExifInterface object
+     * @param redactTags     tags to be redacted
+     */
+    public static void redactExifTags(ExifInterface exifInterface, Set<String> redactTags) {
+        if(redactTags.isEmpty()) return;
+
+         Disposable disposable = Observable.fromIterable(redactTags)
+                 .flatMap(tag -> Observable.fromArray(FileMetadataUtils.getTagsFromPref(tag)))
+                 .forEach(tag -> {
+                     Timber.d("Checking for tag: %s", tag);
+                     String oldValue = exifInterface.getAttribute(tag);
+                     if (oldValue != null && !oldValue.isEmpty()) {
+                         Timber.d("Exif tag %s with value %s redacted.", tag, oldValue);
+                         exifInterface.setAttribute(tag, null);
+                     }
+                 });
+         CompositeDisposable disposables = new CompositeDisposable();
+         disposables.add(disposable);
+         disposables.clear();
+
+         try {
+             exifInterface.saveAttributes();
+        } catch (IOException e) {
+            Timber.w("EXIF redaction failed: %s", e.toString());
+        }
+    }
+
     /**
      * Find other images around the same location that were taken within the last 20 sec
      * @param similarImageInterface

app/src/main/java/fr/free/nrw/commons/upload/UploadModel.java

@@ -109,7 +109,7 @@ private UploadItem getUploadItem(UploadableFile uploadableFile,
             createdTimestampSource = dateTimeWithSource.getSource();
         }
         Timber.d("File created date is %d", fileCreatedDate);
-        GPSExtractor gpsExtractor = fileProcessor.processFileCoordinates(similarImageInterface);
+        GPSExtractor gpsExtractor = fileProcessor.processFileCoordinates(similarImageInterface, context);
         return new UploadItem(uploadableFile.getContentUri(), Uri.parse(uploadableFile.getFilePath()), uploadableFile.getMimeType(context), source, gpsExtractor, place, fileCreatedDate, createdTimestampSource);
     }
 

app/src/main/res/values/arrays.xml

@@ -14,4 +14,25 @@
         <item>@string/license_pref_cc_by_sa_3_0</item>
         <item>@string/license_pref_cc_by_sa_4_0</item>
     </array>
+
+    <!--TODO add more EXIF tags-->
+    <array name="pref_exifTag_entries">
+        <item>@string/exif_tag_name_author</item>
+        <item>@string/exif_tag_name_copyright</item>
+        <item>@string/exif_tag_name_location</item>
+        <item>@string/exif_tag_name_cameraModel</item>
+        <item>@string/exif_tag_name_lensModel</item>
+        <item>@string/exif_tag_name_serialNumbers</item>
+        <item>@string/exif_tag_name_software</item>
+    </array>
+    <array name="pref_exifTag_values">
+        <item>@string/exif_tag_author</item>
+        <item>@string/exif_tag_copyright</item>
+        <item>@string/exif_tag_location</item>
+        <item>@string/exif_tag_cameraModel</item>
+        <item>@string/exif_tag_lensModel</item>
+        <item>@string/exif_tag_serialNumbers</item>
+        <item>@string/exif_tag_software</item>
+    </array>
+
 </resources>

app/src/main/res/values/keys.xml

@@ -5,4 +5,13 @@
     <string name="license_pref_cc_by_sa_3_0" translatable="false">CC BY-SA 3.0</string>
     <string name="license_pref_cc_by_4_0" translatable="false">CC BY 4.0</string>
     <string name="license_pref_cc_by_sa_4_0" translatable="false">CC BY-SA 4.0</string>
+
+    <string name="exif_tag_author" translatable="false">Author</string>
+    <string name="exif_tag_copyright" translatable="false">Copyright</string>
+    <string name="exif_tag_location" translatable="false">Location</string>
+    <string name="exif_tag_cameraModel" translatable="false">Camera Model</string>
+    <string name="exif_tag_lensModel" translatable="false">Lens Model</string>
+    <string name="exif_tag_serialNumbers" translatable="false">Serial Numbers</string>
+    <string name="exif_tag_software" translatable="false">Software</string>
+
 </resources>

app/src/main/res/values/strings.xml

@@ -5,6 +5,7 @@
   <string name="preference_category_appearance">Appearance</string>
   <string name="preference_category_general">General</string>
   <string name="preference_category_feedback">Feedback</string>
+  <string name="preference_category_privacy">Privacy</string>
   <string name="preference_category_location">Location</string>
   <string name="app_name">Commons</string>
   <string name="bullet">&#8226;  </string>
@@ -537,6 +538,18 @@ Upload your first media by tapping on the add button.</string>
   <string name="welcome_dont_upload_content_description">Examples of images not to upload</string>
   <string name="skip_image">SKIP THIS IMAGE</string>
   <string name="download_failed_we_cannot_download_the_file_without_storage_permission">Download Failed!!. We cannot download the file without external storage permission.</string>
+
+  <string name="manage_exif_tags">Manage EXIF Tags</string>
+  <string name="manage_exif_tags_summary">Select which EXIF tags to keep in uploads</string>
+
+  <string name="exif_tag_name_author">Author</string>
+  <string name="exif_tag_name_copyright">Copyright</string>
+  <string name="exif_tag_name_location">Location</string>
+  <string name="exif_tag_name_cameraModel">Camera Model</string>
+  <string name="exif_tag_name_lensModel">Lens Model</string>
+  <string name="exif_tag_name_serialNumbers">Serial Numbers</string>
+  <string name="exif_tag_name_software">Software</string>
+
   <string name="share_text">Upload photos to Wikimedia Commons on your phone Download the Commons app: %1$s</string>
   <string name="share_via">Share app via...</string>
   <string name="image_info">Image Info</string>

app/src/main/res/xml/preferences.xml

@@ -59,6 +59,18 @@
 
     </fr.free.nrw.commons.ui.LongTitlePreferences.LongTitlePreferenceCategory>
 
+    <fr.free.nrw.commons.ui.LongTitlePreferences.LongTitlePreferenceCategory
+        android:title="@string/preference_category_privacy">
+
+        <fr.free.nrw.commons.ui.LongTitlePreferences.LongTitleMultiSelectListPreference
+            android:entries="@array/pref_exifTag_entries"
+            android:entryValues="@array/pref_exifTag_values"
+            android:key="manageExifTags"
+            android:title="@string/manage_exif_tags"
+            android:summary="@string/manage_exif_tags_summary"/>
+
+    </fr.free.nrw.commons.ui.LongTitlePreferences.LongTitlePreferenceCategory>
+
     <!-- The key 'allowGps' was used before and has since been removed based on the discussion at #1599.
           Do not reuse this key unless you revive the same feature with the changes mentioned at #1599.-->
 

app/src/test/kotlin/fr/free/nrw/commons/upload/FileMetadataUtilsTest.kt

@@ -0,0 +1,23 @@
+package fr.free.nrw.commons.upload
+
+import androidx.exifinterface.media.ExifInterface.*
+import junit.framework.Assert.assertTrue
+import org.junit.Test
+import java.util.*
+
+/**
+ * Test cases for FileMetadataUtils
+ */
+class FileMetadataUtilsTest {
+
+    /**
+     * Test method to verify EXIF tags
+     */
+    @Test
+    fun getTagsFromPref() {
+        val author = FileMetadataUtils.getTagsFromPref("Author")
+        val authorRef = arrayOf(TAG_ARTIST, TAG_CAMARA_OWNER_NAME);
+
+        assertTrue(Arrays.deepEquals(author, authorRef))
+    }
+}