feat: ✨ http exceptions and default exception handlers

.vscode/settings.json

@@ -21,7 +21,7 @@
         ".coverage": true,
 
         // 🗑️
-        ".patches": true,
+        // ".patches": true,
         ".venv": true,
         ".vscode": true,
         ".ruff_cache": true,

example/app/data/data.py

@@ -1,6 +1,8 @@
 from datetime import datetime
 from typing import List
 
+from pest.utils.functions import dump_model
+
 from ..modules.todo.models.todo import TodoCreate, TodoModel
 
 default_todos = [
@@ -38,12 +40,7 @@ def next_id() -> int:
             return max([todo.id for todo in self.todos]) + 1
 
         new_todo = TodoModel(
-            **(
-                # HACK: model_dump was added in pydantic@2 and will replace dict()
-                # from @3x onwards; this is a temporary hack to support both
-                # versions until pydantic@2x is widely adopted
-                todo.model_dump() if hasattr(todo, 'model_dump') else todo.dict()
-            ),
+            **(dump_model(todo)),
             id=next_id(),
             done=False,
         )

example/app/modules/todo/services/todo_service.py

@@ -1,5 +1,7 @@
 import fastapi
 
+from pest.exceptions.http.http import ForbiddenException
+
 from ....data.data import TodoRepo
 from ..models.todo import TodoCreate, TodoModel
 
@@ -20,6 +22,14 @@ def get_all(self) -> list[TodoModel]:
         return self.repo.get_all()
 
     def get(self, id: int) -> TodoModel:
+        if (id == 10):
+            # nestjs style http exception raising
+            raise ForbiddenException('Number 10 is reserved for Lionel Messi only')
+
+        if (id == 11):
+            # to test default exception handler
+            raise Exception('This is a test exception')
+
         return validate(self.repo.get_by_id(id))
 
     def create(self, todo: TodoCreate) -> TodoModel:

pest/core/application.py

@@ -15,18 +15,22 @@
 
 from fastapi import FastAPI, Response, routing
 from fastapi.datastructures import Default, DefaultPlaceholder
+from fastapi.exceptions import RequestValidationError, WebSocketRequestValidationError
 from fastapi.params import Depends
 from fastapi.responses import JSONResponse
 from fastapi.types import DecoratedCallable, IncEx
 from fastapi.utils import generate_unique_id
+from pydantic import ValidationError
 from rodi import ActivationScope
+from starlette.exceptions import HTTPException
 from starlette.middleware import Middleware
 from starlette.routing import BaseRoute
 from typing_extensions import Doc
 
 from pest.logging import log
 from pest.middleware.types import CorsOptions
 
+from ..exceptions import handle
 from ..metadata.types.module_meta import InjectionToken
 from ..middleware.base import (
     PestBaseHTTPMiddleware,
@@ -57,7 +61,23 @@ def __init__(
                 for middleware in middleware
             ]
         )
-        print('ok')
+
+        self.add_exception_handlers([
+            (HTTPException, handle.http),
+            (ValidationError, handle.request_validation),
+            (RequestValidationError, handle.request_validation),
+            (WebSocketRequestValidationError, handle.websocket_request_validation),
+
+            # for everything else, there's Mastercard (or was it Bancard? 🤔)
+            (Exception, handle.the_rest),
+        ])
+
+    def add_exception_handlers(
+        self,
+        handlers: list[tuple[int | type[Exception], Callable]]
+    ) -> None:  # pragma: no cover
+        for error, handler in handlers:
+            self.add_exception_handler(error, handler)
 
     def __str__(self) -> str:
         return str(root_module(self))

pest/core/common/__init__.py

@@ -4,7 +4,7 @@
 
 from pest.metadata.types._meta import PestType
 
-from ...utils.exceptions.base import PestException
+from ...exceptions.base.pest import PestException
 from ..types.status import Status
 
 

pest/core/controller.py

@@ -4,11 +4,11 @@
 
 from fastapi.routing import APIRoute
 
+from ..exceptions.base.pest import PestException
 from ..metadata.meta import get_meta, get_meta_value, inject_metadata
 from ..metadata.types._meta import PestType
 from ..metadata.types.controller_meta import ControllerMeta
 from ..metadata.types.handler_meta import HandlerMeta
-from ..utils.exceptions.base import PestException
 from ..utils.fastapi.router import PestRouter
 from .common import PestPrimitive
 from .handler import HandlerTuple, setup_handler

pest/core/module.py

@@ -6,6 +6,7 @@
 import pest.utils.module as module_utils
 from pest.metadata.types._meta import PestType
 
+from ..exceptions.base.pest import PestException
 from ..metadata.meta import get_meta
 from ..metadata.types.module_meta import (
     ClassProvider,
@@ -16,7 +17,6 @@
     Provider,
     ValueProvider,
 )
-from ..utils.exceptions.base import PestException
 from .common import PestPrimitive
 from .controller import Controller, router_of, setup_controller
 from .types.status import Status

pest/utils/exceptions/base.py → pest/exceptions/base/pest.py

@@ -1,10 +1,15 @@
+
 import re
 
-from ..colorize import c
+from ...utils.colorize import c
 
 
 class PestException(Exception):
-    """Base class for all exceptions raised by Pest."""
+    """Base class for all exceptions raised by Pest during setup
+
+    This exception is not meant to be used outside of pest's internals, since it's not
+    handled by any of the asgi exception handlers.
+    """
 
     def __init__(
         self,

pest/exceptions/handle.py

@@ -0,0 +1,78 @@
+from fastapi.encoders import jsonable_encoder
+from fastapi.exceptions import RequestValidationError, WebSocketRequestValidationError
+from fastapi.utils import is_body_allowed_for_status_code
+from fastapi.websockets import WebSocket
+from pydantic import ValidationError
+from starlette.exceptions import HTTPException
+from starlette.requests import Request
+from starlette.responses import JSONResponse, Response
+from starlette.status import WS_1008_POLICY_VIOLATION
+
+from ..utils.functions import dump_model
+from .http.http import ExceptionResponse, PestHTTPException
+from .http.status import HTTPStatusEnum, http_status
+
+
+async def http(request: Request, exc: HTTPException) -> Response:
+    """handles both `HTTPException` (fastapi) and `PestHTTPException` (pest)"""
+
+    headers = getattr(exc, 'headers', None)
+    if not is_body_allowed_for_status_code(exc.status_code):
+        return Response(status_code=exc.status_code, headers=headers)
+
+    if isinstance(exc, PestHTTPException):
+        content = vars(exc)
+    else:
+        content = vars(
+            PestHTTPException(
+                status_code=exc.status_code,
+                detail=exc.detail,
+                headers=headers,
+            )
+        )
+
+    return JSONResponse(
+        status_code=exc.status_code,
+        content=content,
+        headers=headers,
+    )
+
+
+async def request_validation(
+    request: Request, exc: ValidationError | RequestValidationError
+) -> JSONResponse:
+    """handles both `RequestValidationError` (fastapi) and `ValidationError` (pydantic)"""
+
+    stat = http_status(HTTPStatusEnum.HTTP_400_BAD_REQUEST)
+
+    messages = [
+        f"{', '.join([str(elem) for elem in err['loc']])}: {err['msg'].capitalize()}"
+        for err in exc.errors()
+    ]
+
+    return JSONResponse(
+        status_code=stat.code,
+        content=vars(ExceptionResponse(code=stat.code, error=stat.phrase, message=messages)),
+    )
+
+
+async def websocket_request_validation(
+    websocket: WebSocket, exc: WebSocketRequestValidationError
+) -> None:
+    await websocket.close(code=WS_1008_POLICY_VIOLATION, reason=jsonable_encoder(exc.errors()))
+
+
+async def the_rest(request: Request, exc: Exception) -> Response:
+    """handles all other exceptions
+
+    returns a generic 500 response and logs the exception message, just in case it
+    was an
+    """
+
+    stat = http_status(HTTPStatusEnum.HTTP_500_INTERNAL_SERVER_ERROR)
+
+    return JSONResponse(
+        status_code=stat.code, content=dump_model(
+            ExceptionResponse(code=stat.code, error=stat.phrase)
+        )
+    )