btcpayserver/BTCPayServer.Rating/Providers/CoinGeckoRateProvider.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using BTCPayServer.Rating;
using Newtonsoft.Json.Linq;

namespace BTCPayServer.Services.Rates
{
    public class CoinGeckoRateProvider : IRateProvider
    {
        public const string CoinGeckoName = "coingecko";
        // https://api.coingecko.com/api/v3/exchanges/list
        internal static readonly string SupportedExchanges = "[{\"id\":\"abcc\",\"name\":\"ABCC\"},{\"id\":\"acx\",\"name\":\"ACX\"},{\"id\":\"aex\",\"name\":\"AEX\"},{\"id\":\"airswap\",\"name\":\"AirSwap\"},{\"id\":\"allbit\",\"name\":\"Allbit\"},{\"id\":\"allcoin\",\"name\":\"Allcoin\"},{\"id\":\"alterdice\",\"name\":\"AlterDice\"},{\"id\":\"altilly\",\"name\":\"Altilly\"},{\"id\":\"altmarkets\",\"name\":\"Altmarkets\"},{\"id\":\"anx\",\"name\":\"ANX\"},{\"id\":\"aphelion\",\"name\":\"Aphelion\"},{\"id\":\"atomars\",\"name\":\"Atomars\"},{\"id\":\"axnet\",\"name\":\"AXNET\"},{\"id\":\"b2bx\",\"name\":\"B2BX\"},{\"id\":\"bakkt\",\"name\":\"Bakkt\"},{\"id\":\"bamboo_relay\",\"name\":\"Bamboo Relay\"},{\"id\":\"bancor\",\"name\":\"Bancor Network\"},{\"id\":\"bankera\",\"name\":\"Bankera\"},{\"id\":\"basefex\",\"name\":\"BaseFEX\"},{\"id\":\"bcex\",\"name\":\"BCEX\"},{\"id\":\"beaxy\",\"name\":\"Beaxy\"},{\"id\":\"bgogo\",\"name\":\"Bgogo\"},{\"id\":\"bhex\",\"name\":\"BHEX\"},{\"id\":\"bibox\",\"name\":\"Bibox\"},{\"id\":\"bibox_futures\",\"name\":\"Bibox (Futures)\"},{\"id\":\"bigmarkets\",\"name\":\"BIG markets\"},{\"id\":\"bigone\",\"name\":\"BigONE\"},{\"id\":\"bihodl\",\"name\":\"BiHODL \"},{\"id\":\"biki\",\"name\":\"Biki\"},{\"id\":\"bilaxy\",\"name\":\"Bilaxy\"},{\"id\":\"binance\",\"name\":\"Binance\"},{\"id\":\"binance_dex\",\"name\":\"Binance DEX\"},{\"id\":\"binance_futures\",\"name\":\"Binance (Futures)\"},{\"id\":\"binance_jersey\",\"name\":\"Binance Jersey\"},{\"id\":\"binance_us\",\"name\":\"Binance US\"},{\"id\":\"bione\",\"name\":\"Bione\"},{\"id\":\"birake\",\"name\":\"Birake\"},{\"id\":\"bisq\",\"name\":\"Bisq\"},{\"id\":\"bit2c\",\"name\":\"Bit2c\"},{\"id\":\"bitalong\",\"name\":\"Bitalong\"},{\"id\":\"bitasset\",\"name\":\"BitAsset\"},{\"id\":\"bitbank\",\"name\":\"Bitbank\"},{\"id\":\"bitbay\",\"name\":\"BitBay\"},{\"id\":\"bitbegin\",\"name\":\"Bitbegin\"},{\"id\":\"bitbox\",\"name\":\"BITBOX\"},{\"id\":\"bitc3\",\"name\":\"Bitc3\"},{\"id\":\"bitci\",\"name\":\"Bitci\"},{\"id\":\"bitcoin_com\",\"name\":\"Bitcoin.com\"},{\"id\":\"bitcratic\",\"name\":\"Bitcratic\"},{\"id\":\"bitex\",\"name\":\"Bitex.la\"},{\"id\":\"bitexbook\",\"name\":\"BITEXBOOK\"},{\"id\":\"bitexlive\",\"name\":\"Bitexlive\"},{\"id\":\"bitfex\",\"name\":\"Bitfex\"},{\"id\":\"bitfinex\",\"name\":\"Bitfinex\"},{\"id\":\"bitfinex_futures\",\"name\":\"Bitfinex (Futures)\"},{\"id\":\"bitflyer\",\"name\":\"bitFlyer\"},{\"id\":\"bitflyer_futures\",\"name\":\"Bitflyer (Futures)\"},{\"id\":\"bitforex\",\"name\":\"Bitforex\"},{\"id\":\"bitforex_futures\",\"name\":\"Bitforex (Futures)\"},{\"id\":\"bithash\",\"name\":\"BitHash\"},{\"id\":\"bitholic\",\"name\":\"Bithumb Singapore\"},{\"id\":\"bithumb\",\"name\":\"Bithumb\"},{\"id\":\"bithumb_global\",\"name\":\"Bithumb Global\"},{\"id\":\"bitinfi\",\"name\":\"Bitinfi\"},{\"id\":\"bitker\",\"name\":\"BITKER\"},{\"id\":\"bitkonan\",\"name\":\"BitKonan\"},{\"id\":\"bitkub\",\"name\":\"Bitkub\"},{\"id\":\"bitlish\",\"name\":\"Bitlish\"},{\"id\":\"bitmart\",\"name\":\"BitMart\"},{\"id\":\"bitmax\",\"name\":\"BitMax\"},{\"id\":\"bitmesh\",\"name\":\"Bitmesh\"},{\"id\":\"bitmex\",\"name\":\"Bitmex\"},{\"id\":\"bitoffer\",\"name\":\"Bitoffer\"},{\"id\":\"bitonbay\",\"name\":\"BitOnBay\"},{\"id\":\"bitopro\",\"name\":\"BitoPro\"},{\"id\":\"bitpanda\",\"name\":\"Bitpanda Global Exchange\"},{\"id\":\"bitrabbit\",\"name\":\"BitRabbit\"},{\"id\":\"bitrue\",\"name\":\"Bitrue\"},{\"id\":\"bits_blockchain\",\"name\":\"Bits Blockchain\"},{\"id\":\"bitsdaq\",\"name\":\"Bitsdaq\"},{\"id\":\"bitshares_assets\",\"name\":\"Bitshares Assets\"},{\"id\":\"bitso\",\"name\":\"Bitso\"},{\"id\":\"bitsonic\",\"name\":\"Bitsonic\"},{\"id\":\"bitstamp\",\"name\":\"Bitstamp\"},{\"id\":\"bitsten\",\"name\":\"Bitsten\"},{\"id\":\"bitstorage\",\"name\":\"BitStorage\"},{\"id\":\"bittrex\",\"name\":\"Bittrex\"},{\"id\":\"bit_z\",\"name\":\"Bit-Z\"},{\"id\":\"bitz_futures\",\"name\":\"Bitz (Futures)\"},{\"id\":\"bkex\",\"name\":\"BKEX\"},{\"id\":\"bleutrade\",\"name\":\"bleutrade\"},{\"id\":\"blockonix\",\"name\":\"Blockonix\"},
        private readonly HttpClient Client;

        
        public string UnderlyingExchange
        {
            get;
            set;
        }

        public CoinGeckoRateProvider(IHttpClientFactory httpClientFactory)
        {
            if (httpClientFactory == null)
            {
                return;;
            }
            Client = httpClientFactory.CreateClient();
            Client.BaseAddress = new Uri("https://api.coingecko.com/api/v3/");
            Client.DefaultRequestHeaders.Add("Accept", "application/json");
        }

        public virtual Task<PairRate[]> GetRatesAsync(CancellationToken cancellationToken)
        {
            return UnderlyingExchange is null ? GetCoinGeckoRates(cancellationToken) : GetCoinGeckoExchangeSpecificRates(1, cancellationToken);
        }

        private async Task<PairRate[]> GetCoinGeckoRates(CancellationToken cancellationToken)
        {
            using var resp = await GetWithBackoffAsync("exchange_rates", cancellationToken);
            resp.EnsureSuccessStatusCode();
            return JObject.Parse(await resp.Content.ReadAsStringAsync()).GetValue("rates").Children()
                .Where(token => ((JProperty)token).Name != "btc")
                .Select(token => new PairRate(new CurrencyPair("BTC", ((JProperty)token).Name.ToString()),
                    new BidAsk(((JProperty)token).Value["value"].Value<decimal>()))).ToArray();
        }

        private async Task<HttpResponseMessage> GetWithBackoffAsync(string request, CancellationToken cancellationToken)
        {
            TimeSpan retryWait = TimeSpan.FromSeconds(1);
retry:
            var resp = await Client.GetAsync(request, cancellationToken);
            if (resp.StatusCode == System.Net.HttpStatusCode.TooManyRequests)
            {
                resp.Dispose();
                if (retryWait < TimeSpan.FromSeconds(60))
                {
                    await Task.Delay(retryWait, cancellationToken);
                    retryWait = TimeSpan.FromSeconds(retryWait.TotalSeconds * 2);
                    goto retry;
                }
                resp.EnsureSuccessStatusCode();
            }
            return resp;
        }

        private async Task<PairRate[]> GetCoinGeckoExchangeSpecificRates(int page, CancellationToken cancellationToken)
        {
            using var resp = await GetWithBackoffAsync($"exchanges/{UnderlyingExchange}/tickers?page={page}", cancellationToken);

            resp.EnsureSuccessStatusCode();
            List<PairRate> result = JObject.Parse(await resp.Content.ReadAsStringAsync()).GetValue("tickers")
                .Select(token => new PairRate(new CurrencyPair(token.Value<string>("base"), token.Value<string>("target")),
                    new BidAsk(token.Value<decimal>("last")))).ToList();
            if (page == 1 && resp.Headers.TryGetValues("total", out var total) &&
                resp.Headers.TryGetValues("per-page", out var perPage))
            {
                var totalItems = int.Parse(total.First());
                var perPageItems = int.Parse(perPage.First());

                var totalPages = totalItems / perPageItems;
                if (totalItems % perPageItems != 0)
                {
                    totalPages++;
                }

                var tasks = new List<Task<PairRate[]>>();
                for (int i = 2; i <= totalPages; i++)
                {
                    tasks.Add(GetCoinGeckoExchangeSpecificRates(i, cancellationToken));
                }

                foreach (var t in (await Task.WhenAll(tasks)))
                {
                    result.AddRange(t);
                }
            }

            return result.ToArray();
        }
    }
}