Support per exchange params for OHLCV endpoint

freqtrade/exchange/__init__.py

@@ -14,5 +14,6 @@ from freqtrade.exchange.exchange import (available_exchanges, ccxt_exchanges,
                                          timeframe_to_seconds, validate_exchange,
                                          validate_exchanges)
 from freqtrade.exchange.ftx import Ftx
+from freqtrade.exchange.hitbtc import Hitbtc
 from freqtrade.exchange.kraken import Kraken
 from freqtrade.exchange.kucoin import Kucoin

freqtrade/exchange/exchange.py

@@ -59,6 +59,7 @@ class Exchange:
     _ft_has_default: Dict = {
         "stoploss_on_exchange": False,
         "order_time_in_force": ["gtc"],
+        "ohlcv_params": {},
         "ohlcv_candle_limit": 500,
         "ohlcv_partial_candle": True,
         "trades_pagination": "time",  # Possible are "time" or "id"
@@ -874,17 +875,11 @@ class Exchange:
                 "Fetching pair %s, interval %s, since %s %s...",
                 pair, timeframe, since_ms, s
             )
-			#fixing support for HitBTC #4778
-            if self.name== 'HitBTC':
-                data = await self._api_async.fetch_ohlcv(pair, timeframe=timeframe,
-                                                        since=since_ms,
-                                                        limit=self.ohlcv_candle_limit(timeframe),
-                                                        params={"sort": "DESC"}
-                                                         )
-            else:
-                data = await self._api_async.fetch_ohlcv(pair, timeframe=timeframe,
+            params = self._ft_has.get('ohlcv_params', {})
+            data = await self._api_async.fetch_ohlcv(pair, timeframe=timeframe,
                                                      since=since_ms,
-                                                     limit=self.ohlcv_candle_limit(timeframe))
+                                                     limit=self.ohlcv_candle_limit(timeframe),
+                                                     params=params)
 
             # Some exchanges sort OHLCV in ASC order and others in DESC.
             # Ex: Bittrex returns the list of OHLCV in ASC order (oldest first, newest last)

freqtrade/exchange/hitbtc.py

@@ -0,0 +1,26 @@
+""" hitbtx exchange subclass """
+import logging
+from typing import Dict
+
+from freqtrade.exchange import Exchange
+
+
+logger = logging.getLogger(__name__)
+
+
+class Hitbtc(Exchange):
+    """
+    Hitbtc exchange class. Contains adjustments needed for Freqtrade to work
+    with this exchange.
+
+    Please note that this exchange is not included in the list of exchanges
+    officially supported by the Freqtrade development team. So some features
+    may still not work as expected.
+    """
+
+    # fetchCurrencies API point requires authentication for Hitbtc,
+    _ft_has: Dict = {
+        "ohlcv_candle_limit": 1000,
+
+        "ohlcv_params": {"sort": "DESC"}
+    }