Merge pull request #268 from mesozoic/runtime_orm_meta

Allow ORM Meta options to be lookups at runtime (not import time)

docs/source/changelog.rst

@@ -20,6 +20,8 @@ See :ref:`Migrating from 1.x to 2.0` for detailed migration notes.
   - `PR #273 <https://github.com/gtalarico/pyairtable/pull/273>`_.
 * pyAirtable will automatically retry requests when throttled by Airtable's QPS.
   - `PR #272 <https://github.com/gtalarico/pyairtable/pull/272>`_.
+* ORM Meta attributes can now be defined as callables.
+  - `PR #268 <https://github.com/gtalarico/pyairtable/pull/268>`_.
 * Removed ``ApiAbstract``.
   - `PR #267 <https://github.com/gtalarico/pyairtable/pull/267>`_.
 * Implemented strict type annotations on all functions and methods.

pyairtable/orm/model.py

@@ -20,9 +20,9 @@
 
 class Model:
     """
-    This class allows you create an orm-style class for your Airtable tables.
+    This class allows you create an ORM-style class for your Airtable tables.
 
-    This is a meta class and can only be used to define sub-classes.
+    This is a metaclass and can only be used to define sub-classes.
 
     The ``Meta`` is reuired and must specify all three attributes: ``base_id``,
     ``table_id``, and ``api_key``.
@@ -38,6 +38,22 @@ class Model:
     ...         api_key = "keyapikey"
     ...         timeout: Optional[Tuple[int, int]] = (5, 5)
     ...         typecast: bool = True
+
+    You can implement meta attributes as callables if certain values
+    need to be dynamically provided or are unavailable at import time:
+
+    >>> from pyairtable.orm import Model, fields
+    >>> class Contact(Model):
+    ...     first_name = fields.TextField("First Name")
+    ...     age = fields.IntegerField("Age")
+    ...
+    ...     class Meta:
+    ...         base_id = "appaPqizdsNHDvlEm"
+    ...         table_name = "Contact"
+    ...
+    ...         @staticmethod
+    ...         def api_key():
+    ...             return os.environ["AIRTABLE_API_KEY"]
     """
 
     id: str = ""
@@ -125,6 +141,8 @@ def _get_meta(cls, name: str, default: Any = None, required: bool = False) -> An
         if required and not hasattr(cls.Meta, name):
             raise ValueError(f"{cls.__name__}.Meta.{name} must be defined")
         value = getattr(cls.Meta, name, default)
+        if callable(value):
+            value = value()
         if required and value is None:
             raise ValueError(f"{cls.__name__}.Meta.{name} cannot be None")
         return value

tests/test_orm_model.py

@@ -1,3 +1,4 @@
+from functools import partial
 from unittest import mock
 
 import pytest
@@ -118,3 +119,29 @@ def test_from_ids(mock_all):
     with pytest.raises(KeyError):
         FakeModel.from_ids(fake_ids + ["recDefinitelyNotValid"])
     mock_all.assert_called_once()
+
+
+def test_dynamic_model_meta():
+    """
+    Test that we can provide callables in our Meta class to provide
+    the access token, base ID, and table name at runtime.
+    """
+    data = {
+        "api_key": "FakeApiKey",
+        "base_id": "appFakeBaseId",
+        "table_name": "tblFakeTableName",
+    }
+
+    class Fake(Model):
+        class Meta:
+            api_key = lambda: data["api_key"]  # noqa
+            base_id = partial(data.get, "base_id")
+
+            @staticmethod
+            def table_name():
+                return data["table_name"]
+
+    f = Fake()
+    assert f._get_meta("api_key") == data["api_key"]
+    assert f._get_meta("base_id") == data["base_id"]
+    assert f._get_meta("table_name") == data["table_name"]