Implement Formula property (#5)

Co-authored-by: Thomas Rausch <[email protected]>

notion_objects/__init__.py

@@ -3,4 +3,4 @@
 from .properties import *
 from .values import *
 
-__version__ = "0.6.2"
+__version__ = "0.6.3"

notion_objects/properties.py

@@ -33,7 +33,7 @@
     "url",
     "email",
     "phone_number",
-    "formula",  # TODO
+    "formula",
     "relation",
     "rollup",  # TODO
     "created_time",
@@ -413,30 +413,7 @@ def set(self, field: str, value: DateValue, obj: dict):
 
     @staticmethod
     def get_value(field: str, obj: dict) -> DateValue:
-        # TODO: timezone
-
-        start, end = None, None
-        include_time = False
-
-        if container := obj["properties"][field]["date"]:
-            if date_str := container["start"]:
-                start = dateutil.parser.parse(date_str)
-                if len(date_str) > 10:
-                    include_time = True
-
-        if container := obj["properties"][field]["date"]:
-            if date_str := container["end"]:
-                end = dateutil.parser.parse(date_str)
-                if len(date_str) > 10:
-                    include_time = True
-
-        if not include_time:
-            if start:
-                start = start.date()
-            if end:
-                end = end.date()
-
-        return DateValue(start, end, include_time, None)
+        return DateValue.from_dict(obj["properties"][field]["date"])
 
     @staticmethod
     def set_value(field: str, value: DateValue, obj: dict):
@@ -653,6 +630,26 @@ def set(self, field: str, value: List[str], obj: dict):
         PeopleProperty.set_value(field, value, obj)
 
 
+class Formula(Property[Union[str, float, bool, DateValue]]):
+    type = "formula"
+
+    def get(self, field: str, obj: dict) -> Union[str, float, bool, DateValue]:
+        formula = obj["properties"][field][self.type]
+        formula_type = formula["type"]
+
+        if formula_type == "string":
+            return formula["string"]
+        elif formula_type == "number":
+            return formula["number"]
+        elif formula_type == "boolean":
+            return formula["boolean"]
+        elif formula_type == "date":
+            return DateValue.from_dict(formula["date"])
+
+    def set(self, field: str, value: Optional[str], obj: dict):
+        raise NotImplementedError("cannot update the formula of individual records")
+
+
 class Properties(Iterable[_P]):
     factories: Dict[PropertyType, Type[Property]] = {
         "title": TitleText,
@@ -668,6 +665,7 @@ class Properties(Iterable[_P]):
         "checkbox": Checkbox,
         "number": Number,
         "relation": Relation,
+        "formula": Formula,
         # TODO: ...
     }
 

notion_objects/values.py

@@ -2,6 +2,8 @@
 from datetime import date, datetime, tzinfo
 from typing import Optional, Union
 
+import dateutil
+
 
 @dataclass
 class DateValue:
@@ -14,6 +16,28 @@ class DateValue:
     def is_range(self) -> bool:
         return self.end is not None
 
+    @classmethod
+    def from_dict(cls, date_obj: dict) -> "DateValue":
+        # TODO: timezone
+
+        start, end = None, None
+        include_time = False
+
+        if date_obj:
+            if date_str := date_obj.get("start"):
+                start = dateutil.parser.parse(date_str)
+                if len(date_str) > 10:
+                    include_time = True
+                    start = start.date()
+
+            if date_str := date_obj.get("end"):
+                end = dateutil.parser.parse(date_str)
+                if len(date_str) > 10:
+                    include_time = True
+                    end = end.date()
+
+        return cls(start, end, include_time, None)
+
 
 @dataclass
 class UserValue:

tests/integration/test_basic_properties.py

@@ -6,6 +6,7 @@
     Checkbox,
     Database,
     Date,
+    Formula,
     MultiSelect,
     Number,
     Page,
@@ -46,6 +47,7 @@
         },
     },
     "+1": {"people": {}},
+    "Rounded Price": {"formula": {"expression": 'round(prop("Price"))'}},
 }
 
 
@@ -59,6 +61,7 @@ class FoodRecord(Page):
     store_availability = MultiSelect("Store availability")
     upvoted = People("+1")
     description_plain = Text("Description")
+    rounded_price = Formula("Rounded Price")
 
 
 @pytest.fixture()
@@ -97,6 +100,7 @@ def test_create_and_list_records(food_db):
     assert records[0].food_group is None
     assert records[0].store_availability == []
     assert records[0].Price is None
+    assert records[0].rounded_price is None
     assert records[0].last_ordered is None
     assert records[0].description == []
     assert records[0].description_plain == ""
@@ -106,6 +110,7 @@ def test_create_and_list_records(food_db):
     assert records[1].food_group == "Fruit"
     assert records[1].store_availability == ["Duc Loi Market", "Rainbow Grocery"]
     assert records[1].Price == 123.45
+    assert records[1].rounded_price == 123
     assert records[1].last_ordered == now
     assert records[1].description_plain == "hot food record"
     assert records[1].description[0].to_dict() == {
@@ -157,4 +162,5 @@ def test_create_to_dict(food_db):
         "name": "My New Food Record",
         "store_availability": ["Duc Loi Market", "Rainbow Grocery"],
         "upvoted": [],
+        "rounded_price": 123,
     }