public ExchangeController(IMemoryCache memorycache, ILogger <ExchangeController> logger)
{
_exchange_service = new ExchangeService();
_cache = memorycache;
_logger = logger;
_exchange_service.GetExchangeInfo();
List <ExchangeInfo> list = _exchange_service.GetList();
foreach (var item in list)
{
_cache.Set(item.Currency, item, TimeSpan.FromDays(1));
}
}