Support post-only orders for Binance spot

closes #8044

freqtrade/exchange/binance.py

@@ -7,6 +7,7 @@ from typing import Dict, List, Optional, Tuple
 import arrow
 import ccxt
 
+from freqtrade.constants import BuySell
 from freqtrade.enums import CandleType, MarginMode, PriceType, TradingMode
 from freqtrade.exceptions import DDosProtection, OperationalException, TemporaryError
 from freqtrade.exchange import Exchange
@@ -23,7 +24,7 @@ class Binance(Exchange):
     _ft_has: Dict = {
         "stoploss_on_exchange": True,
         "stoploss_order_types": {"limit": "stop_loss_limit"},
-        "order_time_in_force": ['GTC', 'FOK', 'IOC'],
+        "order_time_in_force": ["GTC", "FOK", "IOC", "PO"],
         "ohlcv_candle_limit": 1000,
         "trades_pagination": "id",
         "trades_pagination_arg": "fromId",
@@ -31,6 +32,7 @@ class Binance(Exchange):
     }
     _ft_has_futures: Dict = {
         "stoploss_order_types": {"limit": "stop", "market": "stop_market"},
+        "order_time_in_force": ["GTC", "FOK", "IOC"],
         "tickers_have_price": False,
         "floor_leverage": True,
         "stop_price_type_field": "workingType",
@@ -47,6 +49,26 @@ class Binance(Exchange):
         (TradingMode.FUTURES, MarginMode.ISOLATED)
     ]
 
+    def _get_params(
+        self,
+        side: BuySell,
+        ordertype: str,
+        leverage: float,
+        reduceOnly: bool,
+        time_in_force: str = 'GTC',
+    ) -> Dict:
+        params = super()._get_params(side, ordertype, leverage, reduceOnly, time_in_force)
+        if (
+            time_in_force == 'PO'
+            and ordertype != 'market'
+            and self.trading_mode == TradingMode.SPOT
+            # Only spot can do post only orders
+        ):
+            params.pop('timeInForce')
+            params['postOnly'] = True
+
+        return params
+
     def get_tickers(self, symbols: Optional[List[str]] = None, cached: bool = False) -> Tickers:
         tickers = super().get_tickers(symbols=symbols, cached=cached)
         if self.trading_mode == TradingMode.FUTURES:

tests/exchange/test_binance.py

@@ -11,6 +11,19 @@ from tests.conftest import EXMS, get_mock_coro, get_patched_exchange, log_has_re
 from tests.exchange.test_exchange import ccxt_exceptionhandlers
 
 
+@pytest.mark.parametrize('side,type,time_in_force,expected', [
+    ('buy', 'limit', 'gtc', {'timeInForce': 'GTC'}),
+    ('buy', 'limit', 'IOC', {'timeInForce': 'IOC'}),
+    ('buy', 'market', 'IOC', {}),
+    ('buy', 'limit', 'PO', {'postOnly': True}),
+    ('sell', 'limit', 'PO', {'postOnly': True}),
+    ('sell', 'market', 'PO', {}),
+    ])
+def test__get_params_binance(default_conf, mocker, side, type, time_in_force, expected):
+    exchange = get_patched_exchange(mocker, default_conf, id='binance')
+    assert exchange._get_params(side, type, 1, False, time_in_force) == expected
+
+
 @pytest.mark.parametrize('trademode', [TradingMode.FUTURES, TradingMode.SPOT])
 @pytest.mark.parametrize('limitratio,expected,side', [
     (None, 220 * 0.99, "sell"),

tests/exchange/test_exchange.py

@@ -3387,7 +3387,7 @@ def test_merge_ft_has_dict(default_conf, mocker):
     ex = Binance(default_conf)
     assert ex._ft_has != Exchange._ft_has_default
     assert ex.get_option('stoploss_on_exchange')
-    assert ex.get_option('order_time_in_force') == ['GTC', 'FOK', 'IOC']
+    assert ex.get_option('order_time_in_force') == ['GTC', 'FOK', 'IOC', 'PO']
     assert ex.get_option('trades_pagination') == 'id'
     assert ex.get_option('trades_pagination_arg') == 'fromId'