Change flask KonfigProxy to behave like flask config

docs/changelog.rst

@@ -6,6 +6,9 @@ Changelog
 `Unreleased`_
 -------------
 
+Fixed
+~~~~~
+- Change Flask KonfigProxy to behave like Flask config.
 
 `0.7.2`_ - 2019-07-18
 ---------------------

docs/usage.rst

@@ -585,18 +585,18 @@ Flask extension
 There is an extension for ``Flask`` that replaces ``Flask.config`` with ``Konfig`` instance and adds
 all ``konfetti`` features to your ``app.config``.
 
-```python
-from flask import Flask
-from konfetti.contrib.flask import FlaskKonfig
-from .settings import config
+.. code:: python
+
+    from flask import Flask
+    from konfetti.contrib.flask import FlaskKonfig
+    from .settings import config
 
-app = Flask(__name__)
-FlaskKonfig(app, config, CUSTOM_OPTION=42)
+    app = Flask(__name__)
+    FlaskKonfig(app, config, CUSTOM_OPTION=42)
 
-...
+    ...
 
-# Taken from Vault
-assert app.config.SECRET == "value"
-# Manually specified
-assert app.config.CUSTOM_OPTION == 42
-```
+    # Taken from Vault
+    assert app.config.SECRET == "value"
+    # Manually specified
+    assert app.config.CUSTOM_OPTION == 42

src/konfetti/contrib/flask.py

@@ -28,6 +28,12 @@ class KonfigProxy(object):
     flask_config = attr.ib()
     konfig = attr.ib()
 
+    def get(self, key, default=None):
+        try:
+            return self._get(key)
+        except KeyError:
+            return default
+
     def _get(self, key):
         try:
             return self.kwargs[key]
@@ -40,6 +46,12 @@ def _get(self, key):
     def __getitem__(self, item):
         return self._get(item)
 
+    def __setitem__(self, key, value):
+        self.flask_config[key] = value
+
+    def __contains__(self, item):
+        return self.get(item) is not None
+
     def __getattr__(self, item):
         try:
             return getattr(self.flask_config, item)

test/test_flask.py

@@ -52,3 +52,12 @@ def assert_config(config):
     # Overridden via explicit kwarg
     assert config.SERVER_NAME == "test"
     assert config["SERVER_NAME"] == "test"
+    # Settings flask config item via __setitem__
+    config["CONF_KEY"] = "conf_item"
+    assert config["CONF_KEY"] == "conf_item"
+    # Testing __contains__
+    assert "KEY" in config
+    assert "NOT_EXISTING_KEY" not in config
+    # Testing get method
+    assert config.get("KEY") == "value"
+    assert config.get("NOT_EXISTING_KEY") is None