Extract fields directly from race card files

betfairutil/__init__.py

@@ -1460,6 +1460,25 @@ def open(self, file, *args, **kwargs):
             return _ORIGINAL_OPEN(file, *args, **kwargs)
 
 
+def _load_json_object(o: Union[Dict[str, Any], str, Path]) -> Dict[str, Any]:
+    """
+    Takes either a JSON object and simply returns it or a path to a JSON file containing a JSON
+    object in which case read that file and return the JSON object it contains
+
+    :param o: Either a JSON object or a path to a JSON file containing a JSON object
+    :return: If o is a JSON object then that object; otherwise the JSON object that the file
+        o refers to contains
+    """
+    if isinstance(o, (str, Path)):
+        import orjson
+        import smart_open
+
+        with smart_open.open(o, "r") as f:
+            o = orjson.loads(f.read())
+
+    return o
+
+
 class DataFrameFormatEnum(enum.Enum):
     FULL_LADDER = "FULL_LADDER"
     LAST_PRICE_TRADED = "LAST_PRICE_TRADED"
@@ -2085,12 +2104,7 @@ def get_bsp_from_race_result(
         result object
     :return: a dictionary mapping selection ID to Betfair starting price
     """
-    if isinstance(race_result, (str, Path)):
-        import orjson
-        import smart_open
-
-        with smart_open.open(race_result, "r") as f:
-            race_result = orjson.loads(f.read())
+    race_result = _load_json_object(race_result)
 
     bsp = {}
     for runner in race_result["runners"]:
@@ -2133,15 +2147,39 @@ def get_winners_from_race_result(
     return winning_selection_ids
 
 
-def get_race_distance_in_metres_from_race_card(race_card: Dict[str, Any]) -> float:
+def get_race_distance_in_metres_from_race_card(
+    race_card: Union[Dict[str, Any], str, Path]
+) -> float:
+    """
+    Extract the race distance from a race card object in yards then convert it to metres
+
+    :param race_card: Either the race card object as a dictionary or the path to a JSON file
+        containing the race card object
+    :return: the race distance in metres
+    """
+    race_card = _load_json_object(race_card)
     distance_in_yards = race_card["race"]["distance"]
     distance_in_metres = convert_yards_to_metres(distance_in_yards)
     return distance_in_metres
 
 
 def get_win_market_id_from_race_card(
-    race_card: Dict[str, Any], as_integer: bool = False
+    race_card: Union[Dict[str, Any], str, Path], as_integer: bool = False
 ) -> Optional[Union[int, str]]:
+    """
+    Search the markets contained in a race card for the one corresponding to the Exchange WIN
+    market and return its market ID
+
+    :param race_card: Either the race card object as a dictionary or the path to a JSON file
+        containing the race card object
+    :param as_integer: Should the market ID be returned as is - in the standard string form
+        provided by Betfair that starts "1." - or an integer where the "1." prefix has been
+        discarded
+    :return: The market ID corresponding to the Exchange WIN market, as either an integer or
+        a string according to as_integer, if such a market can be found in the race card
+        otherwise None
+    """
+    race_card = _load_json_object(race_card)
     for market in race_card["race"]["markets"]:
         market_id = market["marketId"]
         if market["marketType"] == "WIN" and market_id.startswith("1."):

tests/test_non_prices.py

@@ -226,6 +226,15 @@ def path_to_race_result_file(race_result: Dict[str, Any], tmp_path: Path):
     return path_to_race_result_file
 
 
+@pytest.fixture
+def path_to_race_card_file(race_card: Dict[str, Any], tmp_path: Path):
+    path_to_race_card_file = tmp_path / "race-card.gz"
+    with smart_open.open(path_to_race_card_file, "w") as f:
+        f.write(json.dumps(race_card))
+
+    return path_to_race_card_file
+
+
 @pytest.fixture
 def path_to_race_file(race_change: Dict[str, Any], tmp_path: Path):
     path_to_race_file = tmp_path / f"31945198.2354.jsonl.gz"
@@ -512,14 +521,24 @@ def test_convert_yards_to_metres():
     assert convert_yards_to_metres(None) is None
 
 
-def test_get_race_distance_in_metres_from_race_card(race_card: Dict[str, Any]):
+def test_get_race_distance_in_metres_from_race_card(
+    race_card: Dict[str, Any], path_to_race_card_file: Path
+):
     assert get_race_distance_in_metres_from_race_card(race_card) == 914.4
+    assert get_race_distance_in_metres_from_race_card(path_to_race_card_file) == 914.4
 
 
-def test_get_win_market_id_from_race_card(race_card: Dict[str, Any]):
+def test_get_win_market_id_from_race_card(
+    race_card: Dict[str, Any], path_to_race_card_file: Path
+):
     assert get_win_market_id_from_race_card(race_card) == "1.456"
     assert get_win_market_id_from_race_card(race_card, as_integer=True) == 456
 
+    assert get_win_market_id_from_race_card(path_to_race_card_file) == "1.456"
+    assert (
+        get_win_market_id_from_race_card(path_to_race_card_file, as_integer=True) == 456
+    )
+
 
 def test_is_market_book(
     market_book: Dict[str, Any],