sembast_cache_manager 1.0.3

A Sembast-based cache manager for the NDK (Nostr Development Kit) library, providing persistent storage for Nostr protocol data.

Sembast Cache Manager

A Sembast-based cache manager specifically designed for the NDK (Nostr Development Kit) library. Provides persistent storage for Nostr protocol data including events, relay information, user profiles, and network responses.

Features

• Persistent Caching: Uses Sembast database for reliable local storage
• TTL Support: Configurable time-to-live for cached entries
• NDK Integration: Implements NDK's CacheManager interface
• Multiple Data Types: Supports events, user profiles, relay lists, and NIP-05 data
• Background Cleanup: Automatic expiration management
• Performance Optimized: Efficient querying and deduplication

Getting started

Add this package to your pubspec.yaml:

dependencies:
  sembast_cache_manager: ^1.0.0
  ndk: ^0.4.0
  sembast: ^3.8.5+1

Then run:

dart pub get

Usage

Basic Setup

import 'dart:io';

import 'package:path_provider/path_provider.dart';
import 'package:sembast_cache_manager/sembast_cache_manager.dart';
import 'package:ndk/ndk.dart';

// Create cache manager
final Directory appDocumentsDir = await getApplicationDocumentsDirectory();
final cacheManager = await SembastCacheManager.create(databasePath: appDocumentsDir.path);

// Configure NDK with cache
final ndkConfig = NdkConfig(
  cache: cacheManager,
  eventVerifier: Bip340EventVerifier(),
);

final ndk = Ndk(ndkConfig);

Cache Operations

// Save and load events
await cacheManager.saveEvent(event);
final cachedEvent = await cacheManager.loadEvent(eventId);

// Save and load user metadata
await cacheManager.saveUserMetadata(metadata);
final userMeta = await cacheManager.loadUserMetadata(pubkey);

// Query events with filters
final events = await cacheManager.loadEvents(
  filter: NostrFilter(kinds: [1], limit: 10)
);

// NIP-05 verification cache
await cacheManager.saveNip05(nip05);
final verification = await cacheManager.loadNip05(internetIdentifier);

Configuration

final config = CacheConfig(
  eventTtl: Duration(hours: 24),
  profileTtl: Duration(days: 7),
  relayTtl: Duration(hours: 1),
  maxEvents: 10000,
  cleanupInterval: Duration(hours: 1),
);

final cacheManager = SembastCacheManager(database, config: config);

Architecture

The cache manager organizes data into separate Sembast stores:

• Events Store: Nostr events indexed by event ID
• Profiles Store: User metadata indexed by pubkey
• Relays Store: Relay information indexed by URL
• NIP-05 Store: Identity verification data

Each cached entry includes:

• Original data
• Timestamp for TTL calculation
• Metadata for filtering and querying

Additional information

• Repository: GitHub
• Issues: Report bugs and feature requests on GitHub
• NDK Compatibility: Designed for NDK v0.4.0+
• License: MIT

For more examples, see the /example folder in the repository.