Add custom exceptions and handling for web errors (#42)

areion/core/exceptions.py

@@ -0,0 +1,62 @@
+"""
+Custom exceptions for Areion.
+
+These are globally handled in the core server.
+"""
+
+
+class HttpError(Exception):
+    """Base class for HTTP errors."""
+
+    status_code: int = 500
+    message: str = "Internal Server Error"
+
+    def __init__(self, message: str = None):
+        if message:
+            self.message = message
+        super().__init__(self.message)
+
+    def __str__(self):
+        return str(self.status_code) + " " + self.message
+
+
+class BadRequestError(HttpError):
+    """400 Bad Request."""
+
+    status_code = 400
+    message = "Bad Request"
+
+
+class UnauthorizedError(HttpError):
+    """401 Unauthorized."""
+
+    status_code = 401
+    message = "Unauthorized"
+
+
+class ForbiddenError(HttpError):
+    """403 Forbidden."""
+
+    status_code = 403
+    message = "Forbidden"
+
+
+class NotFoundError(HttpError):
+    """404 Not Found."""
+
+    status_code = 404
+    message = "Not Found"
+
+
+class MethodNotAllowedError(HttpError):
+    """405 Method Not Allowed."""
+
+    status_code = 405
+    message = "Method Not Allowed"
+
+
+class InternalServerError(HttpError):
+    """500 Internal Server Error."""
+
+    status_code = 500
+    message = "Internal Server Error"

areion/core/server.py

@@ -1,4 +1,6 @@
 import asyncio
+
+from .exceptions import HttpError, NotFoundError
 from .response import HttpResponse
 from .request import HttpRequest
 
@@ -72,23 +74,22 @@ async def _handle_request_logic(self, reader, writer):
         headers = await self._parse_headers(reader)
         request = self.request_factory.create(method, path, headers)
 
+        handler, path_params = self.router.get_handler(method, path)
+
         try:
-            handler, path_params = self.router.get_handler(method, path)
-
-            # Change this to raise 404 exception after thats built
             if not handler:
-                response = HttpResponse(status_code=404, body="Not Found")
-
-            if not path_params:
-                path_params = {}
-
+                raise NotFoundError()
+
             # TODO: Move this to router get handler dict so dont have to do this at runtime
-            # TODO: Simplify
-            if handler and asyncio.iscoroutinefunction(handler):
+            if asyncio.iscoroutinefunction(handler):
                 response = await handler(request, **path_params)
-            elif handler:
+            else:
                 response = handler(request, **path_params)
-        except Exception:
+        except HttpError as e:
+            # Handles web exceptions raised by the handler
+            response = HttpResponse(status_code=e.status_code, body=e)
+        except Exception as e:
+            # Handles all other exceptions
             response = HttpResponse(status_code=500, body="Internal Server Error")
 
         await self._send_response(writer, response)
@@ -104,11 +105,10 @@ async def _parse_headers(self, reader):
         return headers
 
     async def _send_response(self, writer, response):
-        # TODO: Move Response assertion here
         # TODO: Add optional response logging
         if not isinstance(response, HttpResponse):
             response = HttpResponse(body=response)
-            
+
         buffer = response.format_response()
         chunk_size = self.buffer_size