market_interface

A Dart interface library for market data providers, part of the Coin Galaxy ecosystem. This package provides a standardized interface for fetching financial market data including instruments and OHLCV (Open, High, Low, Close, Volume) candlestick data.

Features

• 📊 Standardized Market Interface: Abstract interface for implementing various market data providers
• 🔄 Multiple Instrument Types: Support for spot, perpetual, futures, margin, and options markets
• ⏱️ Flexible Time Intervals: 18 predefined intervals from 1 second to 1 month
• 📈 OHLCV Data: Retrieve candlestick/kline historical data
• 🎯 Type-Safe: Strongly typed enums for instrument types and intervals

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  market_interface: ^0.0.1

Then run:

dart pub get

Usage

Implementing the Market Interface

To create a market data provider, implement the Market abstract class:

import 'package:market_interface/market_interface.dart';
import 'package:finance_kline_core/finance_kline_core.dart';

class MyMarketProvider implements Market {
  @override
  Future<List<String>> getInstruments({required InstrumentType type}) async {
    // Implement logic to fetch available instruments for the given type
    // Example: ['BTC/USDT', 'ETH/USDT', 'SOL/USDT']
    return [];
  }

  @override
  Future<OhlcvSeries> getKlineHistory({
    required String instrument,
    required Interval interval,
    required int limit,
  }) async {
    // Implement logic to fetch OHLCV/candlestick data
    // Returns an OhlcvSeries from finance_kline_core package
    return OhlcvSeries([]);
  }

  @override
  Set<Interval> getSupportedIntervals() {
    // Return the set of intervals your market provider supports
    return {
      Interval.$1m,
      Interval.$5m,
      Interval.$15m,
      Interval.$1h,
      Interval.$4h,
      Interval.$1d,
    };
  }
}

Using a Market Provider

void main() async {
  final market = MyMarketProvider();

  // Get all spot trading pairs
  final spotInstruments = await market.getInstruments(
    type: InstrumentType.spot,
  );
  print('Available spot instruments: $spotInstruments');

  // Fetch 1-hour candlestick data
  final klineData = await market.getKlineHistory(
    instrument: 'BTC/USDT',
    interval: Interval.$1h,
    limit: 100,
  );
  print('Fetched ${klineData.length} candles');

  // Check supported intervals
  final intervals = market.getSupportedIntervals();
  print('Supported intervals: $intervals');
}

API Reference

Market Interface

The main abstract class that must be implemented:

Methods

• getInstruments({required InstrumentType type})

  • Returns a list of available instrument symbols for the specified type
  • Parameters:
    • type: The type of instruments to retrieve (spot, perpetual, futures, margin, options)
  • Returns: FutureOr<List<String>>

• getKlineHistory({required String instrument, required Interval interval, required int limit})

  • Fetches historical OHLCV candlestick data
  • Parameters:
    • instrument: The trading pair symbol (e.g., 'BTC/USDT')
    • interval: The time interval for each candle
    • limit: Maximum number of candles to retrieve
  • Returns: FutureOr<OhlcvSeries>

• getSupportedIntervals()

  • Returns the set of time intervals supported by this market provider
  • Returns: Set<Interval>

InstrumentType Enum

Represents different types of financial instruments:

• spot - Spot trading markets
• perpetual - Perpetual futures/swaps
• futures - Dated futures contracts
• margin - Margin trading markets
• options - Options contracts

Interval Enum

Predefined time intervals for candlestick data:

• Seconds: $1s
• Minutes: $1m, $3m, $5m, $15m, $30m
• Hours: $1h, $2h, $4h, $6h, $8h, $12h
• Days: $1d, $2d, $3d
• Weeks: $1w
• Months: $1M

Dependencies

This package depends on:

• finance_kline_core ^0.0.3 - Core data structures for OHLCV data

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the terms specified in the LICENSE file.

Part of Coin Galaxy

This package is part of the Coin Galaxy ecosystem for cryptocurrency and financial market data processing.

Support

• 🐦 Follow on Twitter: @normidar
• 💖 Sponsor: GitHub Sponsors
• ⭐ Star on GitHub