chest 0.0.1-0

chest: ^0.0.1-0 copied to clipboard

⚠ This package is currently in active development and is not production-ready just yet. Breaking changes are still to be expected. Stay tuned!

An in-memory database with amazing developer experience.

• 🌌 Scalable. Chest can store anything from single ints to huge collections.
• 🎈 Lightweight. Chest is written in pure Dart and has no native dependencies. That also means it works on mobile and desktop.

Chest's philosophy #

What's a database? In its purest form, it's just a place to persist data beyond the lifetime of your app. Chest offers exactly that: persistent variables called chests.

var counter = await Chest.open('counter', ifNew: () => 0);
print('This program ran ${counter.value} times.');
counter.value++;

Like regular variables, chest variables are completely type-safe. Unlike regular variables, they don't actually exist as real Dart objects until you access their value.

But isn't treating databases like variables inefficient? You don't need to save the whole object every time you make a change. Chest allows you to only change part of a value, even if the class is immutable.

var me = await Chest.open('me', ifNew: User());
me.value; // Decodes the whole user.
me.pet.value; // Faster. Only decodes the pet.
me.pet.favoriteFood.color.value = Color.red; // Only changes the part.

Those .value getters and setters are generated automatically.

Wait a minute. How does Chest know how to serialize my types? Chest comes with its own encoding called tape. For built-in types, it already comes prepacked with lots of tapers (serializers for objects). You can annotate your types with @tape and let Chest generate tapers automatically:

@tape
class Fruit {
  final String name;
  final Color color;
}

How does it work? #

Each Chest.open call creates a new Isolate that handles all interactions with the file. This means that we can use the faster, synchronous I/O operations. Also, CPU-heavy tasks like compression don't cause jank in the rest of the app. And the debugging tooling can inspect which isolates are opened and communicate with all of them separately, making it easy to debug them. Only the necessary data is transferred to the main isolate.

Each Chest.open call is condensed to one Chest instance per Isolate. Instances of the same chest – even across multiple Isolates – communicate with the same ChestBackend, which is responsible for actually acessing the file.

+------+ +------+  +------+ +------+
| open | | open |  | open | | open |
+----------------+ +----------------+
| Chest instance | | Chest instance |
+-----------------------------------+
| Chest Backend                     |
+-----------------------------------+
| Files                             |
+-----------------------------------+

Chest instances carry a whole model of the chest's content. The backend is responsible for syncing that model across Isolates and with the file.

TODO before 1.0.0 #

• Support saving to and reading from chests
• Support updating parts of chests
• Support watching (parts of) chests
• Support transactions
• Support references
• Revisit value access syntax
• Write ChestMap
• Write ChestList
• Write ChestSet
• Add cycle detection
• Handle errors gracefully
• Write tapers for various common types
  • dart:core
  • dart:math
  • dart:typed_data
  • tuple
  • Flutter
• Write docs on how to get started
• Write docs on how to write tapers
• Write docs on how it works in principle
• Document the tape format
• Document the file format
• Benchmark
  • Write performance suite.
  • Compare with other databases:
    • Hive & Lazy Hive
    • Sembast
    • SQLite
    • Shared Preferences
• Create ChestTools, a web interface for debugging Chest databases
  • Data
    • See available chests
    • See chests' contents
    • See live updates of the content
    • Edit content
    • Clear chests
    • Change stream
  • Performance
    • Startup
    • Decoding statistics
      • How many decodings are made?
    • How many updates occur?
  • Storage
    • File layout: Base data vs deltas
    • Trigger manual compaction
• Insert events into the Dart Debugging Timeline
• Develop Brand & Logo