Simplify datahandler classes by exploiting commonalities

freqtrade/data/history/idatahandler.py

@@ -12,6 +12,7 @@ from typing import List, Optional, Type
 
 from pandas import DataFrame
 
+from freqtrade import misc
 from freqtrade.configuration import TimeRange
 from freqtrade.constants import ListPairsWithTimeframes, TradeList
 from freqtrade.data.converter import clean_ohlcv_dataframe, trades_remove_duplicates, trim_dataframe
@@ -26,6 +27,13 @@ class IDataHandler(ABC):
     def __init__(self, datadir: Path) -> None:
         self._datadir = datadir
 
+    @classmethod
+    def _get_file_extension(cls) -> str:
+        """
+        Get file extension for this particular datahandler
+        """
+        raise NotImplementedError()
+
     @abstractclassmethod
     def ohlcv_get_available_data(cls, datadir: Path) -> ListPairsWithTimeframes:
         """
@@ -70,7 +78,6 @@ class IDataHandler(ABC):
         :return: DataFrame with ohlcv data, or empty DataFrame
         """
 
-    @abstractmethod
     def ohlcv_purge(self, pair: str, timeframe: str) -> bool:
         """
         Remove data for this pair
@@ -78,6 +85,11 @@ class IDataHandler(ABC):
         :param timeframe: Timeframe (e.g. "5m")
         :return: True when deleted, false if file did not exist.
         """
+        filename = self._pair_data_filename(self._datadir, pair, timeframe)
+        if filename.exists():
+            filename.unlink()
+            return True
+        return False
 
     @abstractmethod
     def ohlcv_append(self, pair: str, timeframe: str, data: DataFrame) -> None:
@@ -123,13 +135,17 @@ class IDataHandler(ABC):
         :return: List of trades
         """
 
-    @abstractmethod
     def trades_purge(self, pair: str) -> bool:
         """
         Remove data for this pair
         :param pair: Delete data for this pair.
         :return: True when deleted, false if file did not exist.
         """
+        filename = self._pair_trades_filename(self._datadir, pair)
+        if filename.exists():
+            filename.unlink()
+            return True
+        return False
 
     def trades_load(self, pair: str, timerange: Optional[TimeRange] = None) -> TradeList:
         """
@@ -141,6 +157,18 @@ class IDataHandler(ABC):
         """
         return trades_remove_duplicates(self._trades_load(pair, timerange=timerange))
 
+    @classmethod
+    def _pair_data_filename(cls, datadir: Path, pair: str, timeframe: str) -> Path:
+        pair_s = misc.pair_to_filename(pair)
+        filename = datadir.joinpath(f'{pair_s}-{timeframe}.{cls._get_file_extension()}')
+        return filename
+
+    @classmethod
+    def _pair_trades_filename(cls, datadir: Path, pair: str) -> Path:
+        pair_s = misc.pair_to_filename(pair)
+        filename = datadir.joinpath(f'{pair_s}-trades.{cls._get_file_extension()}')
+        return filename
+
     def ohlcv_load(self, pair, timeframe: str,
                    timerange: Optional[TimeRange] = None,
                    fill_missing: bool = True,