exportDatabaseLines function

Future<List<Object>> exportDatabaseLines(DatabaseClient client, { List<String>? storeNames, SembastExportOptions? options, })

Return the data in an exported format where each item in the list can be JSONified. If simply encoded as list of json string, it makes it suitable to archive a mutable export on a git file system.

An optional storeNames can specify the list of stores to export. If null All stores are exported.

options can give the stores to export (overriding storeNames) and the encoding of the custom types. Without a type encoding (the legacy export), the custom types are encoded by the database codec (@Timestamp, @Blob by default). With one, they are encoded in it ($Timestamp, $Blob for SembastExportTypeEncoding.dollar) and the header gives it ({"sembast_export": 1, "version": 1, "type_prefix": "$"}, the import reads it). SembastExportTypeEncoding.at from a database whose codec uses @ is the legacy export.

client is a database or a transaction. In a transaction, the export runs in it and includes its changes: writing and exporting can happen in the same transaction.

Implementation

Future<List<Object>> exportDatabaseLines(
  DatabaseClient client, {
  List<String>? storeNames,
  SembastExportOptions? options,
}) async {
  var lines = <Object>[];

  await _exportDatabase(
    client,
    typeEncoding: options?.typeEncoding,
    storeNames: options?.storeNames ?? storeNames,
    exportMeta: (Model map) {
      lines.add(map);
    },
    exportStore: (Model map) {
      lines.add(newModel()..[_store] = map[_name]);
      var keys = map[_keys] as List;
      var values = map[_values] as List;
      for (var i = 0; i < keys.length; i++) {
        lines.add([keys[i], values[i]]);
      }
    },
  );

  return lines;
}