import 'dart:convert'; import 'dart:io'; import 'package:flutter/foundation.dart'; import 'package:path_provider/path_provider.dart'; abstract class JsonCache { final String cacheFileName; JsonCache(this.cacheFileName); Future _getCacheFile() async { final basePath = await getTemporaryDirectory(); final basePathName = basePath.path; final file = File("$basePathName/$cacheFileName.bin"); return file; } Future isValid() async { final file = await _getCacheFile(); return await file.exists(); } Future invalidate() async { try { final file = await _getCacheFile(); await file.delete(); } on FileSystemException { // file is already deleted } } static Future _computeEncodeJson(dynamic toEncode) async { return json.encode(toEncode); } Future putRawData(dynamic data) async { final jsonString = await compute(_computeEncodeJson, data); final file = await _getCacheFile(); if (!await file.exists()) { await file.create(); } await file.writeAsString(jsonString); } static Future _computeDecodeJson(String jsonString) async { return json.decode(jsonString); } Future readRawData() async { final file = await _getCacheFile(); final data = await file.readAsString(); return await compute(_computeDecodeJson, data); } void put(T data); Future get(); }