private async Task AssertProviderAsync(IExchangeRateProvider provider)
{
IEnumerable <ExchangeRate> rates = await provider.GetExchangeRateAsync();
var usdRate = Assert.Single(rates, x => x.Ticker == "USD");
Assert.NotEqual(0.0m, usdRate.Rate);
}
private async Task <decimal> GetRate(ExchangeRateRequest request)
{
if (request.From.Equals(request.To))
{
return(1);
}
var initialRate = (await ExchangeRateProvider.GetExchangeRateAsync(request)).Value;
if (initialRate > 0)
{
return(initialRate);
}
throw new CurrencyExchangeException(request.From, request.To);
}
public async Task <IEnumerable <ExchangeRate> > GetExchangeRatesAsync()
{
if (!_cache.TryGetValue(nameof(GetExchangeRatesAsync), out List <ExchangeRate> exchangeRates))
{
exchangeRates = await _exchangeRateProvider.GetExchangeRateAsync();
if (exchangeRates == null)
{
throw new HttpRequestException("BTC/USD exchange rate is not available.");
}
var cacheEntryOptions = new MemoryCacheEntryOptions()
.SetAbsoluteExpiration(TimeSpan.FromSeconds(20));
_cache.Set(nameof(GetExchangeRatesAsync), exchangeRates, cacheEntryOptions);
}
return(exchangeRates);
}
public async Task <ExchangeResult> Index(string from, string to)
{
return(await _exchangeRateProvider.GetExchangeRateAsync(new ExchangeRateRequest(Currency.GetCurrency(from),
Currency.GetCurrency(to))));
}
public async Task <decimal> ConvertCurrency(string currency, decimal value)
{
var exchangeRate = await _exchangeRateProvider.GetExchangeRateAsync(currency);
return(value * exchangeRate);
}