Exception handlers from settings (#182)

* Make exception handlers load from settings

Author: tarsil

docs/en/docs/release-notes.md

@@ -5,14 +5,14 @@ hide:
 
 # Release Notes
 
-
 ## 0.15.5
 
 ### Added
 
 - Support for multiplexing a session into multiple session contexts.
 - Added support for `redirect_exception` when using [WSGIMiddleware](./middleware.md#wsgimiddleware). This
 flag when passed, you can add a `HTTPException` exception handler that will make Lilya capture the WSGI exceptions.
+- Exception handlers on a global level can now be passed via [settings](./settings.md)
 
 ### Changed
 

lilya/apps.py

@@ -939,7 +939,9 @@ async def populate_g(connection: Connection):
 
         self.debug = self.load_settings_value("debug", debug, is_boolean=True)
 
-        self.exception_handlers = {} if exception_handlers is None else dict(exception_handlers)
+        self.exception_handlers = (
+            self.load_settings_value("exception_handlers", exception_handlers) or {}
+        )
         self.custom_middleware = [
             wrap_middleware(middleware)
             for middleware in self.load_settings_value("middleware", middleware) or []

tests/encoders/settings.py

@@ -1,8 +1,35 @@
 from dataclasses import dataclass
+from json import loads
+from typing import Any
 
+from pydantic import ValidationError
+
+from lilya import status
+from lilya.requests import Request
+from lilya.responses import JSONResponse
+from lilya.types import ExceptionHandler
 from tests.settings import TestSettings
 
 
+async def validation_error_exception_handler(
+    request: Request, exc: ValidationError
+) -> JSONResponse:  # pragma: no cover
+    """
+    This handler is to be used when a pydantic validation error is triggered during the logic
+    of a code block and not the definition of a handler.
+
+    This is different from validation_error_exception_handler
+    """
+    status_code = status.HTTP_422_UNPROCESSABLE_ENTITY
+    return JSONResponse({"detail": loads(exc.json())}, status_code=status_code)
+
+
 @dataclass
 class EncoderSettings(TestSettings):
     infer_body: bool = True
+
+    @property
+    def exception_handlers(self) -> ExceptionHandler | dict[Any, Any]:
+        return {
+            ValidationError: validation_error_exception_handler,
+        }

tests/encoders/test_infer_body_simple_validation.py

@@ -1,28 +1,10 @@
-from json import loads
+from pydantic import BaseModel
 
-from pydantic import BaseModel, ValidationError
-
-from lilya import status
-from lilya.requests import Request
-from lilya.responses import JSONResponse
 from lilya.routing import Path
 from lilya.testclient import create_client
 from tests.encoders.settings import EncoderSettings
 
 
-async def validation_error_exception_handler(
-    request: Request, exc: ValidationError
-) -> JSONResponse:  # pragma: no cover
-    """
-    This handler is to be used when a pydantic validation error is triggered during the logic
-    of a code block and not the definition of a handler.
-
-    This is different from validation_error_exception_handler
-    """
-    status_code = status.HTTP_422_UNPROCESSABLE_ENTITY
-    return JSONResponse({"detail": loads(exc.json())}, status_code=status_code)
-
-
 class User(BaseModel):
     name: str
     age: int
@@ -36,7 +18,6 @@ def test_infer_body_error(test_client_factory):
     with create_client(
         routes=[Path("/infer", handler=process_body, methods=["POST"])],
         settings_module=EncoderSettings,
-        exception_handlers={ValidationError: validation_error_exception_handler},
     ) as client:
         response = client.post("/infer")