add id and url property to database and some docs

notion_objects/database.py

@@ -85,7 +85,7 @@ def _construct(
     ):
         self.database_id = database_id
         self.client = client
-        self.type = mapped_type or DynamicNotionObject
+        self.type = mapped_type or self._from_database_properties
 
     def __iter__(self):
         return self.query(query={"page_size": self.default_page_size})
@@ -110,6 +110,14 @@ def title(self) -> str:
     def _from_database_properties(self, obj: dict) -> DynamicNotionObject:
         return DynamicNotionObject(obj, self.properties)
 
+    @property
+    def id(self) -> str:
+        return self._database_object()["id"]
+
+    @property
+    def url(self) -> str:
+        return self._database_object()["url"]
+
     @lru_cache()
     def _database_object(self):
         return self.client.databases.retrieve(self.database_id)

notion_objects/properties.py

@@ -1,7 +1,7 @@
 import uuid
 from datetime import date, datetime
 from functools import cached_property
-from typing import Any, Dict, Generic, List, Optional, Tuple, Type, TypeVar, Union
+from typing import Any, Dict, Generic, Iterable, List, Optional, Tuple, Type, TypeVar, Union
 
 import dateutil.parser
 
@@ -33,24 +33,47 @@
 ]
 
 _T = TypeVar("_T")
+_P = TypeVar("_P", bound="Property")
 
 
 class Property(Generic[_T]):
+    """
+    A descriptor for mappings between a notion database property and a python attribute.
+
+    """
+
     field: str
+    """The name of the property in the notion database."""
     attr: str
+    """The name of the attribute in the mapped python object."""
     target_type: Optional[Type] = None
+    """The python type this property should be mapped to."""
 
     def __init__(self, field: str = None, object_locator: str = "_obj"):
         self.field = field
         self.attr = field
         self.object_locator = object_locator
 
     def get(self, field: str, obj: dict) -> _T:
+        """
+        Extract from the given field in a notion object the corresponding python value.
+
+        :param field: the notion database property name
+        :param obj: the notion database object
+        :return: a python value representing the value in the notion property
+        """
         raise NotImplementedError(
             f"get operation not implemented for property '{self.__class__.__name__}'"
         )
 
     def set(self, field: str, value: _T, obj: dict):
+        """
+        Maps a given python attribute value to the corresponding notion object property.
+
+        :param field: the notion database property name
+        :param value: the python value to set
+        :param obj: the notion database object
+        """
         raise NotImplementedError(
             f"set operation not implemented for property '{self.__class__.__name__}'"
         )
@@ -96,6 +119,8 @@ def __str__(self):
 
 
 class ChangeTracker:
+    id: str
+
     @cached_property
     def __changes__(self) -> Dict[str, Any]:
         return {}
@@ -448,7 +473,7 @@ def set(self, field: str, value: List[str], obj: dict):
         PeopleProperty.set_value(field, value, obj)
 
 
-class Properties:
+class Properties(Iterable[_P]):
     factories: Dict[str, Type[Property]] = {
         "title": TitleText,
         "created_time": CreatedTime,
@@ -465,14 +490,20 @@ class Properties:
         # TODO: ...
     }
 
-    properties: List[Property]
+    properties: List[_P]
 
-    def __init__(self, properties: List[Property]):
+    def __init__(self, properties: List[_P]):
         self.properties = properties
 
     def __iter__(self):
         return self.properties.__iter__()
 
+    def __getitem__(self, item) -> _P:
+        for prop in self.properties:
+            if prop.field == item:
+                return prop
+        raise KeyError(f"No such property field {item}")
+
     @classmethod
     def parse(cls, obj: dict) -> "Properties":
         created_time = RootProperty("created_time")