FileCache lib

file_cache.dart

import 'dart:io';
import 'dart:convert';

class FileCache {
  // The directory where the cache files are stored
  final Directory cacheDir;

  // The constructor that takes the cache directory as a parameter
  FileCache(this.cacheDir);

  // A function to save data with an expiration date to a file
  Future<void> saveData(String key, dynamic data, Duration expiration) async {
    // Encode the data to JSON format
    String jsonData = jsonEncode(data);

    // Create a file with the key as the name
    File file = File('${cacheDir.path}/$key');

    // Write the data and the expiration date to the file
    await file.writeAsString('$jsonData\n${DateTime.now().add(expiration).toIso8601String()}');
  }

  // A function to load data from a file if it is not expired
  Future<dynamic> loadData(String key) async {
    // Get the file with the key as the name
    File file = File('${cacheDir.path}/$key');

    // Check if the file exists
    if (await file.exists()) {
      // Read the file content as a list of lines
      List<String> lines = await file.readAsLines();

      // Parse the data and the expiration date from the lines
      dynamic data = jsonDecode(lines[0]);
      DateTime expiration = DateTime.parse(lines[1]);

      // Check if the data is expired
      if (DateTime.now().isBefore(expiration)) {
        // Return the data
        return data;
      } else {
        // Delete the file
        await file.delete();

        // Return null
        return null;
      }
    } else {
      // Return null
      return null;
    }
  }
}