Dio HTTP cache interceptor with multiple stores respecting HTTP directives (or not).

HTTP directives:

• ETag
• Last-Modified
• Cache-Control
• Date
• Expires

Stores

• BackupCacheStore: Combined store with primary and secondary.
• DbCacheStore: Cache with database (Moor).
• FileCacheStore: Cache with file system (no web support obviously).
• MemCacheStore: Volatile cache with LRU strategy.

DbCacheStore:

Android - iOS support:

• Add sqlite3_flutter_libs as dependency in your app (version 0.4.0+1 or later).

Desktop support:

• Follow Moor install documentation.

Web support:

• You must include 'sql.js' library. Follow Moor install documentation for further info.

Usage

import 'package:dio_cache_interceptor/dio_cache_interceptor.dart';

// Global options
final options = const CacheOptions(
  store: DbCacheStore(databasePath: 'a_path'), // Required.
  policy: CachePolicy.request, // Default. Checks cache freshness, requests otherwise and caches response.
  hitCacheOnErrorExcept: [401, 403], // Optional. Returns a cached response on error if available but for statuses 401 & 403.
  priority: CachePriority.normal, // Optional. Default. Allows 3 cache sets and ease cleanup.
  maxStale: const Duration(days: 7), // Very optional. Overrides any HTTP directive to delete entry past this duration.
);

// Add cache interceptor with global/default options
final dio = Dio()
  ..interceptors.add(DioCacheInterceptor(options: options),
);

// ...

// Requesting with global options => status code(200)
var response = await dio.get('http://www.foo.com');
// Requesting with global options => status code(304)
response = await dio.get('http://www.foo.com');

// Requesting with dedicated options => status code(200)
response = await dio.get('http://www.foo.com',
  options: options.copyWith(policy: CachePolicy.refresh).toOptions(),
);

Options

CacheOptions is widely available on interceptor and on requests to take precedence.

See documentation for all properties.

Encryption

Optionally, you can encrypt body and headers with your own algorithm via CacheCipher.

Cache policy

enum CachePolicy {
  /// Forces to return the cached value if available.
  /// Requests otherwise.
  /// Caches response regardless directives.
  ///
  /// In short, you'll save every successful GET requests.
  forceCache,

  /// Requests and skips cache save even if
  /// response has cache directives.
  noCache,

  /// Forces to request, even if a valid
  /// cache is available and caches if
  /// response has cache directives.
  refresh,

  /// Returns the cached value if available (and un-expired).
  ///
  /// Checks against origin server otherwise and updates cache freshness
  /// with returned headers.
  ///
  /// Requests otherwise and caches if response has directives.
  request,
}

Features and bugs

Please file feature requests and bugs at the issue tracker.

License

License.