Added a local identity provider. (#1333)

* Added a local identity provider.

* Fixed typo.

* Resetting color, which fallsback to a default in UI.

* Added fallback user, unit tests.

* Removed fallback to base identity provider.

* Added fallback to anonymous user.

Author: 3coins

packages/jupyter-ai/jupyter_ai/auth/identity.py

@@ -0,0 +1,39 @@
+import asyncio
+import getpass
+
+from jupyter_server.auth.identity import IdentityProvider, User
+
+
+def create_initials(username):
+    """Creates initials combining first 2 consonants"""
+
+    username = username.lower()
+
+    # Default: return first two unique consonants
+    consonants = [c for c in username if c in "bcdfghjklmnpqrstvwxyz"]
+    if len(consonants) >= 2:
+        return (consonants[0] + consonants[1]).upper()
+
+    # Fallback: first two characters
+    return username[:2].upper()
+
+
+class LocalIdentityProvider(IdentityProvider):
+    """IdentityProvider that determines username from system user."""
+
+    def get_user(self, handler):
+        try:
+            username = getpass.getuser()
+            user = User(
+                username=username,
+                name=username,
+                initials=create_initials(username),
+                color=None,
+            )
+            return user
+        except OSError as e:
+            self.log.debug(
+                "Could not determine username from system. Falling back to anonymous"
+                f"user."
+            )
+            return self._get_user(handler)

packages/jupyter-ai/jupyter_ai/tests/test_identity.py

@@ -0,0 +1,68 @@
+import logging
+from unittest.mock import Mock, patch
+
+import pytest
+from jupyter_ai.auth.identity import LocalIdentityProvider, create_initials
+from jupyter_server.auth.identity import User
+
+
+@pytest.fixture
+def log():
+    log = logging.getLogger()
+    log.addHandler(logging.NullHandler())
+    return log
+
+
+@pytest.fixture
+def handler():
+    return Mock()
+
+
+@patch("getpass.getuser")
+def test_get_user_successful(getuser, log, handler):
+
+    getuser.return_value = "localuser"
+    provider = LocalIdentityProvider(log=log)
+
+    user = provider.get_user(handler)
+
+    assert isinstance(user, User)
+    assert user.username == "localuser"
+    assert user.name == "localuser"
+    assert user.initials == "LC"
+    assert user.color is None
+
+
+@patch("getpass.getuser")
+@pytest.mark.asyncio
+async def test_get_user_with_error(getuser, log, handler):
+
+    getuser.return_value = "localuser"
+    getuser.side_effect = OSError("Could not get username")
+    handler._jupyter_current_user = User(username="jupyteruser")
+
+    provider = LocalIdentityProvider(log=log)
+
+    user = provider.get_user(handler)
+    user = await user
+
+    assert isinstance(user, User)
+    assert user.username == "jupyteruser"
+
+
+@pytest.mark.parametrize(
+    "username,expected_initials",
+    [
+        ("johndoe", "JH"),
+        ("alice", "LC"),
+        ("xy", "XY"),
+        ("a", "A"),
+        ("SARAH", "SR"),
+        ("john-smith", "JH"),
+        ("john123", "JH"),
+        ("", ""),
+    ],
+)
+def test_create_initials(username, expected_initials):
+    """Test various initials generation scenarios."""
+    assert create_initials(username) == expected_initials.upper()