Add between as a usable operator

examples/fastapi_filter_sqlalchemy.py

@@ -101,6 +101,8 @@ class UserFilter(Filter):
 
     See: https://github.com/tiangolo/fastapi/issues/4700 for why we need to wrap `Query` in `Field`.
     """
+    age__in: Optional[List[int]] = None
+    age__between: Optional[List[List[int]]] = None
     order_by: List[str] = ["age"]
     search: Optional[str] = None
 

fastapi_filter/contrib/sqlalchemy/filter.py

@@ -39,6 +39,7 @@ def _backward_compatible_value_for_like_and_ilike(value: str):
     "isnull": lambda value: ("is_", None) if value is True else ("is_not", None),
     "lt": lambda value: ("__lt__", value),
     "lte": lambda value: ("__le__", value),
+    "between": lambda value: ("between", (value[0], value[1])),
     "like": lambda value: ("like", _backward_compatible_value_for_like_and_ilike(value)),
     "ilike": lambda value: ("ilike", _backward_compatible_value_for_like_and_ilike(value)),
     # XXX(arthurio): Mysql excludes None values when using `in` or `not in` filters.
@@ -89,19 +90,17 @@ class Direction(str, Enum):
 
     @field_validator("*", mode="before")
     def split_str(cls, value, field: ValidationInfo):
-        if (
-            field.field_name is not None
-            and (
+        if field.field_name is not None:
+            if (
                 field.field_name == cls.Constants.ordering_field_name
                 or field.field_name.endswith("__in")
                 or field.field_name.endswith("__not_in")
-            )
-            and isinstance(value, str)
-        ):
-            if not value:
-                # Empty string should return [] not ['']
-                return []
-            return list(value.split(","))
+                or field.field_name.endswith("__between")
+            ) and isinstance(value, str):
+                if not value:
+                    # Empty string should return [] not ['']
+                    return []
+                return list(value.split(","))
         return value
 
     def filter(self, query: Union[Query, Select]):
@@ -124,7 +123,10 @@ def filter(self, query: Union[Query, Select]):
                     query = query.filter(or_(*search_filters))
                 else:
                     model_field = getattr(self.Constants.model, field_name)
-                    query = query.filter(getattr(model_field, operator)(value))
+                    if isinstance(value, tuple):
+                        query = query.filter(getattr(model_field, operator)(*value))
+                    else:
+                        query = query.filter(getattr(model_field, operator)(value))
 
         return query
 

tests/test_sqlalchemy/conftest.py

@@ -274,6 +274,7 @@ class UserFilter(Filter):  # type: ignore[misc, valid-type]
         age__gt: Optional[int] = None
         age__gte: Optional[int] = None
         age__in: Optional[List[int]] = None
+        age__between: Optional[List[int]] = None
         address: Optional[AddressFilter] = FilterDepends(  # type: ignore[valid-type]
             with_prefix("address", AddressFilter), by_alias=True
         )

tests/test_sqlalchemy/test_filter.py

@@ -27,6 +27,8 @@
         [{"address": {"country__not_in": ["France"]}}, 3],
         [{"age__in": "1"}, 1],
         [{"age__in": "21,33"}, 3],
+        [{"age__between": [21, 33]}, 3],
+        [{"age__between": "21,33"}, 3],
         [{"address": {"country__not_in": "France"}}, 3],
         [{"address": {"street__isnull": True}}, 2],
         [{"address": {"city__in": ["Nantes", "Denver"]}}, 3],