Improve error handling and reporting.

- Refactor out common functionality into reusable utilities
- Handle errors from the Authlib library/package
- Handle 4xx errors generically.

1 files changed, 34 insertions, 0 deletions

diff --git a/gn_auth/errors/authlib.py b/gn_auth/errors/authlib.py
new file mode 100644
index 0000000..09862e3
--- /dev/null
+++ b/gn_auth/errors/authlib.py
@@ -0,0 +1,34 @@
+"""Handle authlib errors."""
+import json
+import logging
+
+from authlib.integrations.flask_oauth2.errors import _HTTPException
+
+from gn_auth.errors.common import build_handler
+
+logger = logging.getLogger(__name__)
+
+
+def __description__(body):
+    """Improve description for errors in authlib.oauth2.rfc6749.errors"""
+    _desc = body["error_description"]
+    match body["error"]:
+        case "missing_authorization":
+            return (
+                'The expected "Authorization: Bearer ..." token was not found '
+            'in the headers. Do please try again with the token provided.')
+        case _:
+            return _desc
+
+
+def _http_exception_handler_(exc: _HTTPException):
+    """Handle Authlib's `_HTTPException` errors."""
+    _handle = build_handler(__description__(json.loads(exc.body)))
+    return _handle(exc)
+
+
+def authlib_error_handlers() -> dict:
+    """Return handlers for Authlib errors"""
+    return {
+        _HTTPException: _http_exception_handler_
+    }