# Local Storage

The SDK uses Sembast for local email persistence.

# Setup

# Dart (Native)

import 'package:sembast/sembast_io.dart';

final db = await databaseFactoryIo.openDatabase('emails.db');
final client = NostrMailClient(ndk: ndk, db: db);

# Flutter (Mobile/Desktop)

import 'package:path_provider/path_provider.dart';
import 'package:sembast/sembast_io.dart';

final dir = await getApplicationDocumentsDirectory();
final dbPath = '${dir.path}/emails.db';
final db = await databaseFactoryIo.openDatabase(dbPath);
final client = NostrMailClient(ndk: ndk, db: db);

# Flutter Web

import 'package:sembast_web/sembast_web.dart';

final db = await databaseFactoryWeb.openDatabase('emails');
final client = NostrMailClient(ndk: ndk, db: db);

# Storage Structure

The SDK manages two stores:

Store	Purpose
`emails`	Parsed email records
`processed`	Processed event IDs (deduplication)

# Email Store Schema

{
  "id": "event-id",
  "from": "sender@example.com",
  "to": "recipient@example.com",
  "subject": "Hello",
  "body": "Email body text",
  "date": "2024-12-28T12:00:00.000Z",
  "senderPubkey": "abc123...",
  "rawContent": "From: sender@example.com\nTo: ..."
}

# Operations

# Save Email

Handled automatically by sync() and watchInbox():

await _store.saveEmail(email);

# Get Emails

// All emails (sorted by date, newest first)
final emails = await client.getEmails();

// With pagination
final page = await client.getEmails(limit: 20, offset: 0);

# Get Single Email

final email = await client.getEmail('event-id');

# Delete Email

await client.delete('event-id');

# Deduplication

The processed store prevents reprocessing:

// Check if already processed
if (await _store.isProcessed(eventId)) {
  return; // Skip
}

// Mark as processed
await _store.markProcessed(eventId);

# Database Management

# Clear All Data

await db.close();
// Delete the database file

# Backup

The database is a single file that can be copied for backup.

# Cross-Platform Considerations

Platform	Factory	Path
Mobile	`sembast_io`	`getApplicationDocumentsDirectory()`
Desktop	`sembast_io`	`getApplicationDocumentsDirectory()`
Web	`sembast_web`	IndexedDB (browser)

# Example: Platform-Aware Initialization

import 'package:flutter/foundation.dart' show kIsWeb;
import 'package:sembast/sembast.dart';

Future<Database> openEmailDatabase() async {
  if (kIsWeb) {
    return await databaseFactoryWeb.openDatabase('emails');
  } else {
    final dir = await getApplicationDocumentsDirectory();
    return await databaseFactoryIo.openDatabase('${dir.path}/emails.db');
  }
}