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Akavache V11.0: An Asynchronous Key-Value Store for Native Applications

Akavache is an asynchronous, persistent (i.e., writes to disk) key-value store created for writing desktop and mobile applications in C#, based on SQLite3. Akavache is great for both storing important data (i.e., user settings) as well as cached local data that expires.

What's New in V11.0

Akavache V11.0 introduces a new Builder Pattern for initialization, improved serialization support, and enhanced cross-serializer compatibility:

• 🏗️ Builder Pattern: New fluent API for configuring cache instances
• 🔄 Multiple Serializer Support: Choose between System.Text.Json, Newtonsoft.Json, each with a BSON variant
• 🔗 Cross-Serializer Compatibility: Read data written by different serializers
• 🧩 Modular Design: Install only the packages you need
• 📱 Enhanced .NET MAUI Support: First-class support for modern cross-platform development
• 🔒 Improved Security: Better encrypted cache implementation

Development History

Akavache V11.0 represents a significant evolution in the library's architecture, developed through extensive testing and community feedback in our incubator project. The new features and improvements in V11.0 were first prototyped and battle-tested in the ReactiveMarbles.CacheDatabase repository, which served as an experimental ground for exploring new caching concepts and architectural patterns.

Key Development Milestones:

• 🧪 Incubation Phase: The builder pattern, modular serialization system, and enhanced API were first developed and tested in ReactiveMarbles.CacheDatabase
• 🔬 Community Testing: Early adopters and contributors provided valuable feedback on the new architecture through real-world usage scenarios
• 🚀 Production Validation: The incubator project allowed us to validate performance improvements, API ergonomics, and cross-platform compatibility before integrating into Akavache
• 📈 Iterative Refinement: Multiple iterations based on community feedback helped shape the final V11.0 API design and feature set

This careful incubation process ensured that V11.0 delivers not just new features, but a more robust, flexible, and maintainable caching solution that builds upon years of community experience and testing. The ReactiveMarbles organization continues to serve as a proving ground for innovative reactive programming concepts that eventually make their way into the broader ReactiveUI ecosystem.

Table of Contents

• Quick Start
• Installation
• Migration from V10.x
• Configuration
• Serializers
• Cache Types
• Basic Operations
• Extension Methods
• Advanced Features
• Platform-Specific Notes
• Performance
• Best Practices

Quick Start

1. Install Packages

<PackageReference Include="Akavache.Sqlite3" Version="11.0.*" />
<PackageReference Include="Akavache.SystemTextJson" Version="11.0.*" />

2. Initialize Akavache

Note:

WithAkavache WithAkavacheCacheDatabase and Initialize always requires an ISerializer defined as a generic type, such as WithAkavache<SystemJsonSerializer>. This ensures the cache instance is properly configured for serialization.

Static Initialization (Recommended for most apps)

using Akavache.Core;
using Akavache.SystemTextJson;
using Akavache.Sqlite3;
using Splat.Builder;

// Initialize with the builder pattern
AppBuilder.CreateSplatBuilder()
 .WithAkavacheCacheDatabase<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithSqliteProvider() // Use SQLite backend - new in V11.0.2 + (Required for Sqlite, this is to avoid confusion between Sqlite and EncryptedSqlite which both have `Batteries_V2.Init();` calls)
 .WithSqliteDefaults());

Dependency Injection Registration (for DI containers)

using Akavache.Core;
using Akavache.SystemTextJson;
using Akavache.Sqlite3;
using Splat.Builder;

// Example: Register Akavache with Splat DI
AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(
 "MyApp",
 builder => builder.WithSqliteDefaults(),
 (splat, instance) => splat.RegisterLazySingleton(() => instance));

// For in-memory cache (testing or lightweight scenarios):
AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(
 "Akavache",
 builder => builder.WithInMemoryDefaults(),
 (splat, instance) => splat.RegisterLazySingleton(() => instance));

Manual Instance Creation (advanced scenarios)

using Akavache.Core;
using Akavache.SystemTextJson;
using Akavache.Sqlite3;

var akavacheInstance = CacheDatabase.CreateBuilder()
 .WithSerializer<SystemJsonSerializer>()
 .WithApplicationName("MyApp")
 .WithSqliteProvider()
 .WithSqliteDefaults()
 .Build();

// Use akavacheInstance.UserAccount, akavacheInstance.LocalMachine, etc.

3. Use the Cache

// Store an object
var user = new User { Name = "John", Email = "john@example.com" };
await CacheDatabase.UserAccount.InsertObject("current_user", user);

// Retrieve an object
var cachedUser = await CacheDatabase.UserAccount.GetObject<User>("current_user");

// Store with expiration
await CacheDatabase.LocalMachine.InsertObject("temp_data", someData, DateTimeOffset.Now.AddHours(1));

// Get or fetch pattern
var data = await CacheDatabase.LocalMachine.GetOrFetchObject("api_data", 
 async () => await httpClient.GetFromJsonAsync<ApiResponse>("https://api.example.com/data"));

Installation

Akavache V11.0 uses a modular package structure. Choose the packages that match your needs:

Core Package (Included with Serializers, In Memory only)

<PackageReference Include="Akavache" Version="11.0.**" />

Sqlite Storage Backends (recommended)

<PackageReference Include="Akavache.Sqlite3" Version="11.0.**" />


<PackageReference Include="Akavache.EncryptedSqlite3" Version="11.0.**" />

Serializers (Choose One (Required!))

<PackageReference Include="Akavache.SystemTextJson" Version="11.0.**" />


<PackageReference Include="Akavache.NewtonsoftJson" Version="11.0.**" />

Optional Extensions

<PackageReference Include="Akavache.Drawing" Version="11.0.**" />


<PackageReference Include="Akavache.Settings" Version="11.0.**" />

Migration from V10.x

Breaking Changes

1. Initialization Method: The BlobCache.ApplicationName and Registrations.Start() methods are replaced with the builder pattern
2. Package Structure: Akavache is now split into multiple packages
3. Serializer Registration: Must explicitly register a serializer before use

Migration Steps

Old V10.x Code:

// V10.x initialization
BlobCache.ApplicationName = "MyApp";
// or
Akavache.Registrations.Start("MyApp");

// Usage
var data = await BlobCache.UserAccount.GetObject<MyData>("key");
await BlobCache.LocalMachine.InsertObject("key", myData);

New V11.0 Code:

// V11.0 initialization

AppBuilder.CreateSplatBuilder()
 .WithAkavacheCacheDatabase<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp") 
 .WithSqliteProvider()
 .WithSqliteDefaults());

// Usage (same API)
var data = await CacheDatabase.UserAccount.GetObject<MyData>("key");
await CacheDatabase.LocalMachine.InsertObject("key", myData);

Migration Helper

Create this helper method to ease migration:

public static class AkavacheMigration
{
 public static void InitializeV11(string appName)
 {
 // Initialize with SQLite (most common V10.x setup)
 CacheDatabase
 .Initialize<SystemJsonSerializer>(builder =>
 builder
 .WithSqliteProvider()
 .WithSqliteDefaults(),
 appName);
 }
}

// Then in your app:
AkavacheMigration.InitializeV11("MyApp");

Configuration

Builder Pattern

Akavache V11.0 uses a fluent builder pattern for configuration:

AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp") // Required
 .WithSqliteProvider() // Initialize SQLite backend
 .WithSqliteDefaults()); // SQLite persistence

Configuration Options

1. In-Memory Only (for testing or non retensive applications)

AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("TestApp")
 .WithInMemoryDefaults());

2. SQLite Persistence

AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithSqliteProvider()
 .WithSqliteDefaults());

3. Encrypted SQLite

AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithEncryptedSqliteProvider()
 .WithSqliteDefaults("mySecretPassword"));

4. Custom Cache Instances

AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithEncryptedSqliteProvider()
 .WithUserAccount(new SqliteBlobCache("custom-user.db"))
 .WithLocalMachine(new SqliteBlobCache("custom-local.db"))
 .WithSecure(new EncryptedSqliteBlobCache("secure.db", "password"))
 .WithInMemory(new InMemoryBlobCache()));

5. DateTime Handling

// Set global DateTime behavior
AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithSqliteProvider()
 .WithForcedDateTimeKind(DateTimeKind.Utc)
 .WithSqliteDefaults());

Serializers

Akavache V11.0 supports multiple serialization formats with automatic cross-compatibility.

System.Text.Json (Recommended)

Best for: New applications, performance-critical scenarios, .NET native support

Features:

• ✅ Fastest performance
• ✅ Native .NET support
• ✅ Smallest memory footprint
• ✅ BSON compatibility mode available
• ❌ Limited customization options

Configuration:

var serializer = new SystemJsonSerializer()
{
 UseBsonFormat = false, // true for max compatibility with old data
 Options = new JsonSerializerOptions
 {
 PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
 WriteIndented = false
 }
};

Newtonsoft.Json (Maximum Compatibility)

Best for: Migrating from older Akavache versions, complex serialization needs

Features:

• ✅ Maximum compatibility with existing data
• ✅ Rich customization options
• ✅ BSON compatibility mode
• ✅ Complex type support
• ❌ Larger memory footprint
• ❌ Slower than System.Text.Json

Configuration:

var serializer = new NewtonsoftSerializer()
{
 UseBsonFormat = true, // Recommended for Akavache compatibility
 Options = new JsonSerializerSettings
 {
 DateTimeZoneHandling = DateTimeZoneHandling.Utc,
 NullValueHandling = NullValueHandling.Ignore
 }
};

Once configured, pass the serializer type to the builder:

AppBuilder.CreateSplatBuilder()
 .WithAkavache<NewtonsoftSerializer>(
 () => serializer,
 builder =>
 builder.WithApplicationName("MyApp")
 .WithSqliteProvider()
 .WithSqliteDefaults());

BSON Variants

For maximum backward compatibility with existing Akavache data: use UseBsonFormat = true in either serializer.

Cache Types

Akavache provides four types of caches, each with different characteristics:

UserAccount Cache

Purpose: User settings and preferences that should persist and potentially sync across devices.

// Store user preferences
var settings = new UserSettings { Theme = "Dark", Language = "en-US" };
await CacheDatabase.UserAccount.InsertObject("user_settings", settings);

// Retrieve preferences
var userSettings = await CacheDatabase.UserAccount.GetObject<UserSettings>("user_settings");

Platform Behavior:

• iOS/macOS: Backed up to iCloud
• Windows: May be synced via Microsoft Account
• Android: Stored in internal app data

LocalMachine Cache

Purpose: Cached data that can be safely deleted by the system.

// Cache API responses
var apiData = await httpClient.GetFromJsonAsync<ApiResponse>("https://api.example.com/data");
await CacheDatabase.LocalMachine.InsertObject("api_cache", apiData, DateTimeOffset.Now.AddHours(6));

// Retrieve with fallback
var cachedData = await CacheDatabase.LocalMachine.GetOrFetchObject("api_cache",
 () => httpClient.GetFromJsonAsync<ApiResponse>("https://api.example.com/data"));

Platform Behavior:

• iOS: May be deleted by system when storage is low
• Android: Subject to cache cleanup policies
• Windows/macOS: Stored in temp/cache directories

Secure Cache

Purpose: Encrypted storage for sensitive data like credentials and API keys.

// Store credentials
await CacheDatabase.Secure.SaveLogin("john.doe", "secretPassword", "myapp.com");

// Retrieve credentials
var loginInfo = await CacheDatabase.Secure.GetLogin("myapp.com");
Console.WriteLine($"User: {loginInfo.UserName}, Password: {loginInfo.Password}");

// Store API keys
await CacheDatabase.Secure.InsertObject("api_key", "sk-1234567890abcdef");
var apiKey = await CacheDatabase.Secure.GetObject<string>("api_key");

InMemory Cache

Purpose: Temporary storage that doesn't persist between app sessions.

// Cache session data
var sessionData = new SessionInfo { UserId = 123, SessionToken = "abc123" };
await CacheDatabase.InMemory.InsertObject("current_session", sessionData);

// Fast temporary storage
await CacheDatabase.InMemory.InsertObject("temp_calculation", expensiveResult);

Basic Operations

Storing Data

// Store simple objects
await CacheDatabase.UserAccount.InsertObject("key", myObject);

// Store with expiration
await CacheDatabase.LocalMachine.InsertObject("temp_key", data, DateTimeOffset.Now.AddMinutes(30));

// Store multiple objects
var keyValuePairs = new Dictionary<string, MyData>
{
 ["key1"] = new MyData { Value = 1 },
 ["key2"] = new MyData { Value = 2 }
};
await CacheDatabase.UserAccount.InsertObjects(keyValuePairs);

// Store raw bytes
await CacheDatabase.LocalMachine.Insert("raw_key", Encoding.UTF8.GetBytes("Hello World"));

Retrieving Data

// Get single object
var data = await CacheDatabase.UserAccount.GetObject<MyData>("key");

// Get multiple objects
var keys = new[] { "key1", "key2", "key3" };
var results = await CacheDatabase.UserAccount.GetObjects<MyData>(keys).ToList();

// Get all objects of a type
var allData = await CacheDatabase.UserAccount.GetAllObjects<MyData>().ToList();

// Get raw bytes
var rawData = await CacheDatabase.LocalMachine.Get("raw_key");

Error Handling

// Handle missing keys
try
{
 var data = await CacheDatabase.UserAccount.GetObject<MyData>("nonexistent_key");
}
catch (KeyNotFoundException)
{
 // Key not found
 var defaultData = new MyData();
}

// Use fallback pattern
var data = await CacheDatabase.UserAccount.GetObject<MyData>("key")
 .Catch(Observable.Return(new MyData()));

Removing Data

// Remove single object
await CacheDatabase.UserAccount.InvalidateObject<MyData>("key");

// Remove multiple objects
await CacheDatabase.UserAccount.InvalidateObjects<MyData>(new[] { "key1", "key2" });

// Remove all objects of a type
await CacheDatabase.UserAccount.InvalidateAllObjects<MyData>();

// Remove all data
await CacheDatabase.UserAccount.InvalidateAll();

Extension Methods

Get or Fetch Pattern

The most common pattern for caching remote data:

// Basic get-or-fetch
var userData = await CacheDatabase.LocalMachine.GetOrFetchObject("user_profile",
 async () => await apiClient.GetUserProfile(userId));

// With expiration
var weatherData = await CacheDatabase.LocalMachine.GetOrFetchObject("weather",
 async () => await weatherApi.GetCurrentWeather(),
 DateTimeOffset.Now.AddMinutes(30));

// With custom fetch observable
var liveData = await CacheDatabase.LocalMachine.GetOrFetchObject("live_data",
 () => Observable.Interval(TimeSpan.FromSeconds(5))
 .Select(_ => DateTime.Now.ToString()));

Get and Fetch Latest

Returns cached data immediately, then fetches fresh data:

// Subscribe to get both cached and fresh data
CacheDatabase.LocalMachine.GetAndFetchLatest("news_feed",
 () => newsApi.GetLatestNews())
 .Subscribe(news => 
 {
 // This will be called twice:
 // 1. Immediately with cached data (if available)
 // 2. When fresh data arrives from the API
 UpdateUI(news);
 });

HTTP/URL Operations

// Download and cache URLs
var imageData = await CacheDatabase.LocalMachine.DownloadUrl("https://example.com/image.jpg");

// With custom headers
var headers = new Dictionary<string, string>
{
 ["Authorization"] = "Bearer " + token,
 ["User-Agent"] = "MyApp/1.0"
};
var apiResponse = await CacheDatabase.LocalMachine.DownloadUrl("https://api.example.com/data", 
 HttpMethod.Get, headers);

// Force fresh download
var freshData = await CacheDatabase.LocalMachine.DownloadUrl("https://api.example.com/live", 
 fetchAlways: true);

Login/Credential Management

// Save login credentials (encrypted)
await CacheDatabase.Secure.SaveLogin("username", "password", "myapp.com");

// Retrieve credentials
var loginInfo = await CacheDatabase.Secure.GetLogin("myapp.com");
Console.WriteLine($"User: {loginInfo.UserName}");

// Multiple hosts
await CacheDatabase.Secure.SaveLogin("user1", "pass1", "api.service1.com");
await CacheDatabase.Secure.SaveLogin("user2", "pass2", "api.service2.com");

Advanced Features

Relative Time Extensions

// Cache for relative time periods
await CacheDatabase.LocalMachine.InsertObject("data", myData, TimeSpan.FromMinutes(30).FromNow());

// Use in get-or-fetch
var cachedData = await CacheDatabase.LocalMachine.GetOrFetchObject("api_data",
 () => FetchFromApi(),
 1.Hours().FromNow());

Custom Schedulers

// Use custom scheduler for background operations
CacheDatabase.TaskpoolScheduler = TaskPoolScheduler.Default;

// Or use a custom scheduler
CacheDatabase.TaskpoolScheduler = new EventLoopScheduler();

Cache Inspection

// Get all keys (for debugging)
var allKeys = await CacheDatabase.UserAccount.GetAllKeys().ToList();

// Check when item was created
var createdAt = await CacheDatabase.UserAccount.GetCreatedAt("my_key");
if (createdAt.HasValue)
{
 Console.WriteLine($"Item created at: {createdAt.Value}");
}

// Get creation times for multiple keys
var creationTimes = await CacheDatabase.UserAccount.GetCreatedAt(new[] { "key1", "key2" })
 .ToList();

Cache Maintenance

// Force flush all pending operations
await CacheDatabase.UserAccount.Flush();

// Vacuum database (SQLite only - removes deleted data)
await CacheDatabase.UserAccount.Vacuum();

// Flush specific object type
await CacheDatabase.UserAccount.Flush(typeof(MyDataType));

Mixed Object Storage

// Store different types with one operation
var mixedData = new Dictionary<string, object>
{
 ["string_data"] = "Hello World",
 ["number_data"] = 42,
 ["object_data"] = new MyClass { Value = "test" },
 ["date_data"] = DateTime.Now
};

await CacheDatabase.UserAccount.InsertObjects(mixedData);

Akavache.Drawing

Akavache.Drawing provides comprehensive image caching and bitmap manipulation functionality for Akavache applications. Built on Splat, it offers cross-platform support for loading, caching, and manipulating images with enhanced features beyond basic blob storage.

Features

• Image Loading & Caching: Load images from cache with automatic format detection
• URL Image Caching: Download and cache images from URLs with built-in HTTP support
• Image Manipulation: Resize, crop, and generate thumbnails with caching
• Multiple Format Support: PNG, JPEG, GIF, BMP, WebP, and other common formats
• Fallback Support: Automatic fallback to default images when loading fails
• Batch Operations: Load multiple images efficiently
• Size Detection: Get image dimensions without full loading
• Advanced Caching: Pattern-based cache clearing and preloading
• Cross-Platform: Works on all .NET platforms supported by Akavache

Installation

<PackageReference Include="Akavache.Drawing" Version="11.0.*" />

Dependencies

Akavache.Drawing requires:

• Akavache.Core - Core caching functionality
• Splat.Drawing - Cross-platform bitmap abstractions

Basic Usage

1. Initialize Drawing Support

using Akavache.Core;
using Akavache.Drawing;
using Akavache.SystemTextJson;
using Splat;

// Initialize Akavache with drawing support
CacheDatabase.Initialize<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyImageApp")
 .WithSqliteProvider()
 .WithSqliteDefaults());

// Register platform-specific bitmap loader using Splat (if needed (Net 8.0+))
AppLocator.CurrentMutable.RegisterPlatformBitmapLoader();

2. Load Images from Cache

// Load image from cache
var image = await CacheDatabase.LocalMachine.LoadImage("user_avatar");

// Load with custom sizing
var thumbnail = await CacheDatabase.LocalMachine.LoadImage("user_avatar", 150, 150);

// Load with error handling
try
{
 var profileImage = await CacheDatabase.UserAccount.LoadImage("profile_pic");
 DisplayImage(profileImage);
}
catch (KeyNotFoundException)
{
 // Image not found in cache
 ShowDefaultImage();
}

3. Load Images from URLs

// Download and cache image from URL
var imageFromUrl = await CacheDatabase.LocalMachine
 .LoadImageFromUrl("https://example.com/images/photo.jpg");

// With custom expiration
var tempImage = await CacheDatabase.LocalMachine
 .LoadImageFromUrl("https://api.example.com/temp-image.png", 
 absoluteExpiration: DateTimeOffset.Now.AddHours(1));

// Force fresh download (bypass cache)
var freshImage = await CacheDatabase.LocalMachine
 .LoadImageFromUrl("https://api.example.com/live-feed.jpg", fetchAlways: true);

// With custom key
var namedImage = await CacheDatabase.LocalMachine
 .LoadImageFromUrl("user_background", "https://example.com/bg.jpg");

4. Save Images to Cache

// Save image to cache
await CacheDatabase.LocalMachine.SaveImage("user_photo", bitmap);

// Save with expiration
await CacheDatabase.LocalMachine.SaveImage("temp_image", bitmap, 
 DateTimeOffset.Now.AddDays(7));

// Convert bitmap to bytes for manual storage
var imageBytes = await bitmap.ImageToBytes().FirstAsync();
await CacheDatabase.LocalMachine.Insert("raw_image_data", imageBytes);

Advanced Features

Batch Image Operations

// Load multiple images at once
var imageKeys = new[] { "image1", "image2", "image3" };
var loadedImages = await CacheDatabase.LocalMachine
 .LoadImages(imageKeys, desiredWidth: 200, desiredHeight: 200)
 .ToList();

foreach (var kvp in loadedImages)
{
 Console.WriteLine($"Loaded {kvp.Key}: {kvp.Value.Width}x{kvp.Value.Height}");
}

// Preload images from URLs (background caching)
var urls = new[]
{
 "https://example.com/image1.jpg",
 "https://example.com/image2.jpg",
 "https://example.com/image3.jpg"
};

await CacheDatabase.LocalMachine.PreloadImagesFromUrls(urls, 
 DateTimeOffset.Now.AddDays(1));

Image Fallbacks

// Load image with automatic fallback
var defaultImageBytes = File.ReadAllBytes("default-avatar.png");

var userAvatar = await CacheDatabase.UserAccount
 .LoadImageWithFallback("user_avatar", defaultImageBytes, 100, 100);

// Load from URL with fallback
var profileImage = await CacheDatabase.LocalMachine
 .LoadImageFromUrlWithFallback("https://example.com/profile.jpg", 
 defaultImageBytes, 
 desiredWidth: 200, 
 desiredHeight: 200);

Thumbnail Generation

// Create and cache thumbnail from existing image
await CacheDatabase.LocalMachine.CreateAndCacheThumbnail(
 sourceKey: "original_photo",
 thumbnailKey: "photo_thumb", 
 thumbnailWidth: 150, 
 thumbnailHeight: 150,
 absoluteExpiration: DateTimeOffset.Now.AddDays(30));

// Load the cached thumbnail
var thumbnail = await CacheDatabase.LocalMachine.LoadImage("photo_thumb");

Image Size Detection

// Get image dimensions without fully loading
var imageSize = await CacheDatabase.LocalMachine.GetImageSize("large_image");
Console.WriteLine($"Image size: {imageSize.Width}x{imageSize.Height}");
Console.WriteLine($"Aspect ratio: {imageSize.AspectRatio:F2}");

// Use size info for layout decisions
if (imageSize.AspectRatio > 1.5)
{
 // Wide image
 SetWideImageLayout();
}
else
{
 // Square or tall image
 SetNormalImageLayout();
}

Cache Management

// Clear images matching a pattern
await CacheDatabase.LocalMachine.ClearImageCache(key => key.StartsWith("temp_"));

// Clear all user avatars
await CacheDatabase.UserAccount.ClearImageCache(key => key.Contains("avatar"));

// Clear expired images
await CacheDatabase.LocalMachine.ClearImageCache(key => 
 key.StartsWith("cache_") && IsExpired(key));

Complete Example: Photo Gallery App

public class PhotoGalleryService
{
 private readonly IBlobCache _imageCache;
 private readonly IBlobCache _thumbnailCache;

 public PhotoGalleryService()
 {
 // Initialize Akavache with drawing support
 AppBuilder.CreateSplatBuilder().WithAkavacheCacheDatabase<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("PhotoGallery")
 .WithSqliteProvider()
 .WithSqliteDefaults());

 _imageCache = CacheDatabase.LocalMachine;
 _thumbnailCache = CacheDatabase.UserAccount;
 }

 public async Task<IBitmap> LoadPhotoAsync(string photoId, bool generateThumbnail = false)
 {
 try
 {
 // Try to load from cache first
 var photo = await _imageCache.LoadImage($"photo_{photoId}");
 
 // Generate thumbnail if requested and not exists
 if (generateThumbnail)
 {
 await _thumbnailCache.CreateAndCacheThumbnail(
 $"photo_{photoId}", 
 $"thumb_{photoId}", 
 200, 200,
 DateTimeOffset.Now.AddMonths(1));
 }
 
 return photo;
 }
 catch (KeyNotFoundException)
 {
 // Load from remote URL if not cached
 var photoUrl = $"https://api.photos.com/images/{photoId}";
 return await _imageCache.LoadImageFromUrl($"photo_{photoId}", photoUrl, 
 absoluteExpiration: DateTimeOffset.Now.AddDays(7));
 }
 }

 public async Task<IBitmap> LoadThumbnailAsync(string photoId)
 {
 try
 {
 return await _thumbnailCache.LoadImage($"thumb_{photoId}", 200, 200);
 }
 catch (KeyNotFoundException)
 {
 // Generate thumbnail from full image
 var fullImage = await LoadPhotoAsync(photoId);
 await _thumbnailCache.SaveImage($"thumb_{photoId}", fullImage, 
 DateTimeOffset.Now.AddMonths(1));
 return await _thumbnailCache.LoadImage($"thumb_{photoId}", 200, 200);
 }
 }

 public async Task PreloadGalleryAsync(IEnumerable<string> photoIds)
 {
 var photoUrls = photoIds.Select(id => $"https://api.photos.com/images/{id}");
 await _imageCache.PreloadImagesFromUrls(photoUrls, 
 DateTimeOffset.Now.AddDays(7));
 }

 public async Task ClearOldCacheAsync()
 {
 // Clear images older than 30 days
 await _imageCache.ClearImageCache(key => 
 key.StartsWith("photo_") && IsOlderThan30Days(key));
 
 // Clear thumbnails older than 60 days 
 await _thumbnailCache.ClearImageCache(key => 
 key.StartsWith("thumb_") && IsOlderThan60Days(key));
 }

 private static bool IsOlderThan30Days(string key) => 
 /* Implementation to check cache age */ false;
 
 private static bool IsOlderThan60Days(string key) => 
 /* Implementation to check cache age */ false;
}

Akavache.Settings

Akavache.Settings provides a specialized settings database for installable applications. It creates persistent settings that are stored one level down from the application folder, making application updates less painful as the settings survive reinstalls.

Features

• Type-Safe Settings: Strongly-typed properties with default values
• Automatic Persistence: Settings are automatically saved when changed
• Application Update Friendly: Settings survive application reinstalls
• Encrypted Storage: Optional secure settings with password protection
• Multiple Settings Classes: Support for multiple settings categories

Installation

<PackageReference Include="Akavache.Settings" Version="11.0.*" />

Basic Usage

1. Create a Settings Class

using Akavache.Settings;

public class AppSettings : SettingsBase
{
 public AppSettings() : base(nameof(AppSettings))
 {
 }

 // Boolean setting with default value
 public bool EnableNotifications
 {
 get => GetOrCreate(true);
 set => SetOrCreate(value);
 }

 // String setting with default value
 public string UserName
 {
 get => GetOrCreate("DefaultUser");
 set => SetOrCreate(value);
 }

 // Numeric settings
 public int MaxRetries
 {
 get => GetOrCreate(3);
 set => SetOrCreate(value);
 }

 public double CacheTimeout
 {
 get => GetOrCreate(30.0);
 set => SetOrCreate(value);
 }

 // Enum setting
 public LogLevel LoggingLevel
 {
 get => GetOrCreate(LogLevel.Information);
 set => SetOrCreate(value);
 }
}

public enum LogLevel
{
 Debug,
 Information,
 Warning,
 Error
}

2. Initialize Settings Store

using Akavache.Core;
using Akavache.SystemTextJson;
using Akavache.Settings;

// Initialize Akavache with settings support
var appSettings = default(AppSettings);

AppBuilder.CreateSplatBuilder().WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithSerializer(new SystemJsonSerializer())
 .WithSqliteProvider()
 .WithSettingsStore<AppSettings>(settings => appSettings = settings));

// Now use the settings
appSettings.EnableNotifications = false;
appSettings.UserName = "John Doe";
appSettings.MaxRetries = 5;

Console.WriteLine($"User: {appSettings.UserName}");
Console.WriteLine($"Notifications: {appSettings.EnableNotifications}");

Advanced Configuration

Custom Settings Cache Path

By default, settings are stored in a subfolder of your application directory. You can customize this path:

AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithSqliteProvider()
 .WithSettingsCachePath(@"C:\MyApp\Settings") // Custom path
 .WithSettingsStore<AppSettings>(settings => appSettings = settings));

Multiple Settings Classes

You can create multiple settings classes for different categories:

public class UserSettings : SettingsBase
{
 public UserSettings() : base(nameof(UserSettings)) { }
 
 public string Theme
 {
 get => GetOrCreate("Light");
 set => SetOrCreate(value);
 }
}

public class NetworkSettings : SettingsBase
{
 public NetworkSettings() : base(nameof(NetworkSettings)) { }
 
 public int TimeoutSeconds
 {
 get => GetOrCreate(30);
 set => SetOrCreate(value);
 }
}

// Initialize multiple settings
var userSettings = default(UserSettings);
var networkSettings = default(NetworkSettings);

AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithSqliteProvider()
 .WithSettingsStore<UserSettings>(settings => userSettings = settings)
 .WithSettingsStore<NetworkSettings>(settings => networkSettings = settings));

Encrypted Settings

For sensitive settings, use encrypted storage:

public class SecureSettings : SettingsBase
{
 public SecureSettings() : base(nameof(SecureSettings)) { }
 
 public string ApiKey
 {
 get => GetOrCreate(string.Empty);
 set => SetOrCreate(value);
 }
 
 public string DatabasePassword
 {
 get => GetOrCreate(string.Empty);
 set => SetOrCreate(value);
 }
}

// Initialize with encryption
var secureSettings = default(SecureSettings);

AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithEncryptedSqliteProvider()
 .WithSecureSettingsStore<SecureSettings>("mySecurePassword", 
 settings => secureSettings = settings));

// Use encrypted settings
secureSettings.ApiKey = "sk-1234567890abcdef";
secureSettings.DatabasePassword = "super-secret-password";

Override Database Names

You can specify custom database names for settings:

var appSettings = default(AppSettings);

AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithSqliteProvider()
 .WithSettingsStore<AppSettings>(
 settings => appSettings = settings, 
 "CustomAppConfig")); // Custom database name

Complete Example

Here's a comprehensive example showing all data types and features:

public class ComprehensiveSettings : SettingsBase
{
 public ComprehensiveSettings() : base(nameof(ComprehensiveSettings))
 {
 }

 // Basic types with defaults
 public bool BoolSetting
 {
 get => GetOrCreate(true);
 set => SetOrCreate(value);
 }

 public byte ByteSetting
 {
 get => GetOrCreate((byte)123);
 set => SetOrCreate(value);
 }

 public short ShortSetting
 {
 get => GetOrCreate((short)16);
 set => SetOrCreate(value);
 }

 public int IntSetting
 {
 get => GetOrCreate(42);
 set => SetOrCreate(value);
 }

 public long LongSetting
 {
 get => GetOrCreate(123456L);
 set => SetOrCreate(value);
 }

 public float FloatSetting
 {
 get => GetOrCreate(2.5f);
 set => SetOrCreate(value);
 }

 public double DoubleSetting
 {
 get => GetOrCreate(3.14159);
 set => SetOrCreate(value);
 }

 public string StringSetting
 {
 get => GetOrCreate("Default Value");
 set => SetOrCreate(value);
 }

 // Nullable types
 public string? NullableStringSetting
 {
 get => GetOrCreate<string?>(null);
 set => SetOrCreate(value);
 }

 // Complex types (automatically serialized)
 public List<string> StringListSetting
 {
 get => GetOrCreate(new List<string> { "Item1", "Item2" });
 set => SetOrCreate(value);
 }

 public Dictionary<string, int> DictionarySetting
 {
 get => GetOrCreate(new Dictionary<string, int> { ["Key1"] = 1, ["Key2"] = 2 });
 set => SetOrCreate(value);
 }

 // Custom objects
 public WindowPosition WindowPosition
 {
 get => GetOrCreate(new WindowPosition { X = 100, Y = 100, Width = 800, Height = 600 });
 set => SetOrCreate(value);
 }
}

public class WindowPosition
{
 public int X { get; set; }
 public int Y { get; set; }
 public int Width { get; set; }
 public int Height { get; set; }
}

// Usage
var settings = default(ComprehensiveSettings);
AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithSqliteProvider()
 .WithSettingsStore<ComprehensiveSettings>(s => settings = s));

// Use the settings
settings.StringListSetting.Add("Item3");
settings.WindowPosition = new WindowPosition { X = 200, Y = 150, Width = 1024, Height = 768 };
settings.DictionarySetting["NewKey"] = 999;

Settings Lifecycle Management

Cleanup on Application Exit

// In your application shutdown code
public async Task OnApplicationExit()
{
 var builder = CacheDatabase.Builder;
 
 // Dispose settings stores to ensure data is flushed
 await builder.DisposeSettingsStore<AppSettings>();
 await builder.DisposeSettingsStore<UserSettings>();
 
 // Regular Akavache shutdown
 await CacheDatabase.Shutdown();
}

Delete Settings (Reset to Defaults)

// Delete a specific settings store
var builder = CacheDatabase.Builder;
await builder.DeleteSettingsStore<AppSettings>();

// Settings will be recreated with default values on next access

Check if Settings Exist

var builder = CacheDatabase.Builder;
var existingSettings = builder.GetSettingsStore<AppSettings>();

if (existingSettings != null)
{
 Console.WriteLine("Settings already exist");
}
else
{
 Console.WriteLine("First run - settings will be created with defaults");
}

Platform-Specific Notes

.NET MAUI

// In MauiProgram.cs
public static class MauiProgram
{
 public static MauiApp CreateMauiApp()
 {
 var builder = MauiApp.CreateBuilder();
 builder.UseMauiApp<App>();

 // Initialize Akavache early
 AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(cacheBuilder =>
 cacheBuilder.WithApplicationName("MyMauiApp")
 .WithSqliteProvider()
 .WithForceDateTimeKind(DateTimeKind.Utc)
 .WithSqliteDefaults());

 return builder.Build();
 }
}

WPF Applications

// In App.xaml.cs
public partial class App : Application
{
 protected override void OnStartup(StartupEventArgs e)
 {
 ConfigureAkavache();
 base.OnStartup(e);
 }

 protected override void OnExit(ExitEventArgs e)
 {
 // Important: Shutdown Akavache properly
 CacheDatabase.Shutdown().Wait();
 base.OnExit(e);
 }

 private static void ConfigureAkavache()
 {
 AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyWpfApp")
 .WithSqliteProvider()
 .WithForceDateTimeKind(DateTimeKind.Utc)
 .WithSqliteDefaults());
 }
}

iOS Specific

// In AppDelegate.cs or SceneDelegate.cs
public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
{
 AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyiOSApp")
 .WithSqliteProvider()
 .WithSqliteDefaults());

 return base.FinishedLaunching(application, launchOptions);
}

Android Specific

// In MainActivity.cs or Application class
protected override void OnCreate(Bundle savedInstanceState)
{
 base.OnCreate(savedInstanceState);

 AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyAndroidApp")
 .WithSqliteProvider()
 .WithSqliteDefaults());
}

UWP Applications

// In App.xaml.cs
protected override void OnLaunched(LaunchActivatedEventArgs e)
{
 AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyUwpApp")
 .WithSqliteProvider()
 .WithSqliteDefaults());

 // Rest of initialization...
}

Important for UWP: Mark your application as x86 or ARM, not Any CPU.

Performance

Benchmarks

Performance comparison of different serializers (operations per second):

Operation	System.Text.Json	Newtonsoft.Json	BSON
Serialize small object	50,000	25,000	20,000
Deserialize small object	45,000	22,000	18,000
Serialize large object	5,000	2,500	2,000
Deserialize large object	4,500	2,200	1,800

Performance Reports

For comprehensive performance analysis and V10 vs V11 comparison:

• 📊 - Quick comparison and migration decision matrix
• 📈 - Detailed performance analysis, architectural differences, and recommendations

Performance Tips

// 1. Use System.Text.Json for best performance
.WithSerializer<SystemJsonSerializer>();

// 2. Use batch operations for multiple items
await CacheDatabase.UserAccount.InsertObjects(manyItems);

// 3. Set appropriate expiration times
await CacheDatabase.LocalMachine.InsertObject("temp", data, 30.Minutes().FromNow());

// 4. Use InMemory cache for frequently accessed data
await CacheDatabase.InMemory.InsertObject("hot_data", frequentData);

// 5. Avoid storing very large objects
// Instead, break them into smaller chunks or use compression

// 6. Use specific types instead of object when possible
await CacheDatabase.UserAccount.GetObject<SpecificType>("key"); // Good
await CacheDatabase.UserAccount.Get("key", typeof(SpecificType)); // Slower

Best Practices

1. Initialization

// ✅ Do: Initialize once at app startup
public class App
{
 static App()
 {
 AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("MyApp")
 .WithSqliteProvider()
 .WithSqliteDefaults());
 }
}

// ❌ Don't: Initialize multiple times

2. Key Naming

// ✅ Do: Use consistent, descriptive key naming
await CacheDatabase.UserAccount.InsertObject("user_profile_123", userProfile);
await CacheDatabase.LocalMachine.InsertObject("api_cache_weather_seattle", weatherData);

// ✅ Do: Use constants for keys
public static class CacheKeys
{
 public const string UserProfile = "user_profile";
 public const string WeatherData = "weather_data";
}

// ❌ Don't: Use random or inconsistent keys
await CacheDatabase.UserAccount.InsertObject("xyz123", someData);

3. Error Handling

// ✅ Do: Handle KeyNotFoundException appropriately
try
{
 var data = await CacheDatabase.UserAccount.GetObject<MyData>("key");
}
catch (KeyNotFoundException)
{
 // Provide fallback or default behavior
 var defaultData = new MyData();
}

// ✅ Do: Use GetOrFetchObject for remote data
var data = await CacheDatabase.LocalMachine.GetOrFetchObject("api_data",
 () => httpClient.GetFromJsonAsync<ApiData>("https://api.example.com/data"));

4. Cache Types Usage

// ✅ Do: Use appropriate cache types
await CacheDatabase.UserAccount.InsertObject("user_settings", settings); // Persistent user data
await CacheDatabase.LocalMachine.InsertObject("api_cache", apiData); // Cacheable data
await CacheDatabase.Secure.InsertObject("api_key", apiKey); // Sensitive data
await CacheDatabase.InMemory.InsertObject("session_data", sessionData); // Temporary data

5. Expiration

// ✅ Do: Set appropriate expiration times
await CacheDatabase.LocalMachine.InsertObject("api_data", data, 1.Hours().FromNow());
await CacheDatabase.LocalMachine.InsertObject("image_cache", imageBytes, 1.Days().FromNow());

// ✅ Do: Don't expire user settings (unless necessary)
await CacheDatabase.UserAccount.InsertObject("user_preferences", prefs); // No expiration

6. Shutdown

// ✅ Do: Always shutdown Akavache properly
public override void OnExit(ExitEventArgs e)
{
 CacheDatabase.Shutdown().Wait();
 base.OnExit(e);
}

// For MAUI/Xamarin apps
protected override void OnSleep()
{
 CacheDatabase.Shutdown().Wait();
 base.OnSleep();
}

7. Testing

// ✅ Do: Use in-memory cache for unit tests
[SetUp]
public void Setup()
{
 CacheDatabase.Initialize<SystemJsonSerializer>(builder =>
 builder.WithApplicationName("TestApp")
 .WithInMemoryDefaults());
}

[TearDown]
public void TearDown()
{
 CacheDatabase.Shutdown().Wait();
}

Troubleshooting

Common Issues

1. "No serializer has been registered"

// Fix: Register a suitable serializer during initialization
CacheDatabase.Initialize<SystemJsonSerializer>(/* ... */);

AppBuilder.CreateSplatBuilder()
 .WithAkavache<SystemJsonSerializer>(/* ... */);

AppBuilder.CreateSplatBuilder()
 .WithAkavacheCacheDatabase<SystemJsonSerializer>(/* ... */);

2. "CacheDatabase has not been initialized"

// Fix: Call Initialize before using cache
CacheDatabase.Initialize<SystemJsonSerializer>(builder => builder.WithApplicationName("MyApp").WithInMemoryDefaults());
var data = await CacheDatabase.UserAccount.GetObject<MyData>("key");

3. Data compatibility issues

// Fix: Use cross-compatible serializer or migration
CacheDatabase.Initialize<NewtonsoftBsonSerializer>(/* ... */); // Most compatible

4. SQLite errors on mobile

// Fix: Ensure SQLitePCL.raw bundle is installed
// Add to your project:
<ItemGroup>
 <PackageReference Include="SQLitePCLRaw.bundle_green" Version="2.1.11" />
 
// If using Encrypted SQLite, also add:
 <PackageReference Include="SQLitePCLRaw.bundle_e_sqlcipher" Version="2.1.11" />
</ItemGroup>

5. Linker removing types IL2104

You will need to preserve certain types to prevent the linker from stripping them out in release builds.

// Add to your .csproj file:
<ItemGroup>
 <TrimmerRootAssembly Include="SQLitePCLRaw.lib.e_sqlite3.## YOUR-PLATFORM ##" RootMode="All" />
</ItemGroup>

### Platform-Specific Issues

#### iOS Linker Issues
```csharp
// Add LinkerPreserve.cs to your iOS project:
public static class LinkerPreserve
{
 static LinkerPreserve()
 {
 var sqliteBlobCachetName = typeof(SqliteBlobCache).FullName;
 var encryptedSqliteBlobCacheName = typeof(EncryptedSqliteBlobCache).FullName;
 }
}

UWP x64 Issues

Ensure your UWP project targets a specific platform (x86, x64, ARM) rather than "Any CPU".

Support and Contributing

• 📖 Documentation: https://github.com/reactiveui/Akavache
• 🐛 Issues: GitHub Issues
• 💬 Chat: ReactiveUI Slack
• 📦 NuGet: Akavache Packages

License

Akavache is licensed under the .