Share local vaults from Android

androidsrc/org/julianfamily/keepassgo/AndroidShare.java

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+package org.julianfamily.keepassgo;
+
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+
+public final class AndroidShare {
+    private static final String DEFAULT_TITLE = "KeePassGO Vault";
+
+    private AndroidShare() {
+    }
+
+    public static void shareVault(Context context, String path, String title) throws IOException {
+        File source = new File(path);
+        if (!source.isFile()) {
+            throw new IOException("vault file not found: " + path);
+        }
+        File shared = copyToSharedExport(context, source);
+        Uri uri = SharedVaultProvider.uriForFile(shared.getName());
+
+        Intent send = new Intent(Intent.ACTION_SEND);
+        send.setType("application/x-keepass2");
+        send.putExtra(Intent.EXTRA_STREAM, uri);
+        send.putExtra(Intent.EXTRA_TITLE, sanitizeTitle(title, source.getName()));
+        send.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+
+        Intent chooser = Intent.createChooser(send, "Share vault");
+        chooser.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+        chooser.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+        context.startActivity(chooser);
+    }
+
+    static File sharedDirectory(Context context) {
+        return new File(new File(context.getFilesDir(), "keepassgo"), "shared");
+    }
+
+    private static File copyToSharedExport(Context context, File source) throws IOException {
+        File dir = sharedDirectory(context);
+        if (!dir.exists() && !dir.mkdirs()) {
+            throw new IOException("failed to create " + dir.getAbsolutePath());
+        }
+        File target = new File(dir, sanitizeFilename(source.getName()));
+        try (FileInputStream in = new FileInputStream(source);
+             FileOutputStream out = new FileOutputStream(target, false)) {
+            byte[] buffer = new byte[8192];
+            int count;
+            while ((count = in.read(buffer)) >= 0) {
+                out.write(buffer, 0, count);
+            }
+        }
+        return target;
+    }
+
+    private static String sanitizeFilename(String name) {
+        String trimmed = name == null ? "" : name.trim();
+        if (trimmed.isEmpty()) {
+            return "shared-vault.kdbx";
+        }
+        if (trimmed.endsWith(".kdbx")) {
+            return trimmed;
+        }
+        return trimmed + ".kdbx";
+    }
+
+    private static String sanitizeTitle(String title, String fallbackName) {
+        String trimmed = title == null ? "" : title.trim();
+        if (!trimmed.isEmpty()) {
+            return trimmed;
+        }
+        String fallback = fallbackName == null ? "" : fallbackName.trim();
+        if (!fallback.isEmpty()) {
+            return fallback;
+        }
+        return DEFAULT_TITLE;
+    }
+}

androidsrc/org/julianfamily/keepassgo/SharedVaultProvider.java

@@ -0,0 +1,100 @@
+package org.julianfamily.keepassgo;
+
+import android.content.ContentProvider;
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.database.MatrixCursor;
+import android.net.Uri;
+import android.os.ParcelFileDescriptor;
+import android.provider.OpenableColumns;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+
+public final class SharedVaultProvider extends ContentProvider {
+    private static final String AUTHORITY = "org.julianfamily.keepassgo.share";
+
+    @Override
+    public boolean onCreate() {
+        return true;
+    }
+
+    @Override
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
+        File file = resolveSharedFile(uri);
+        String[] columns = projection;
+        if (columns == null || columns.length == 0) {
+            columns = new String[]{OpenableColumns.DISPLAY_NAME, OpenableColumns.SIZE};
+        }
+        MatrixCursor cursor = new MatrixCursor(columns, 1);
+        Object[] row = new Object[columns.length];
+        for (int i = 0; i < columns.length; i++) {
+            switch (columns[i]) {
+                case OpenableColumns.DISPLAY_NAME:
+                    row[i] = file.getName();
+                    break;
+                case OpenableColumns.SIZE:
+                    row[i] = file.length();
+                    break;
+                default:
+                    row[i] = null;
+                    break;
+            }
+        }
+        cursor.addRow(row);
+        return cursor;
+    }
+
+    @Override
+    public String getType(Uri uri) {
+        return "application/x-keepass2";
+    }
+
+    @Override
+    public Uri insert(Uri uri, ContentValues values) {
+        throw new UnsupportedOperationException("insert is not supported");
+    }
+
+    @Override
+    public int delete(Uri uri, String selection, String[] selectionArgs) {
+        throw new UnsupportedOperationException("delete is not supported");
+    }
+
+    @Override
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+        throw new UnsupportedOperationException("update is not supported");
+    }
+
+    @Override
+    public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
+        File file = resolveSharedFile(uri);
+        return ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY);
+    }
+
+    static Uri uriForFile(String name) {
+        return new Uri.Builder()
+                .scheme("content")
+                .authority(AUTHORITY)
+                .appendPath(name)
+                .build();
+    }
+
+    private File resolveSharedFile(Uri uri) {
+        if (getContext() == null) {
+            throw new IllegalStateException("provider context is unavailable");
+        }
+        String name = sanitizeFilename(uri.getLastPathSegment());
+        return new File(AndroidShare.sharedDirectory(getContext()), name);
+    }
+
+    private static String sanitizeFilename(String name) {
+        if (name == null) {
+            return "shared-vault.kdbx";
+        }
+        String trimmed = name.trim();
+        if (trimmed.isEmpty()) {
+            return "shared-vault.kdbx";
+        }
+        return new File(trimmed).getName();
+    }
+}