First product

app/api/errors.py

@@ -0,0 +1,85 @@
+from __future__ import annotations
+
+from typing import Any
+
+from fastapi import FastAPI, HTTPException, Request
+from fastapi.exception_handlers import (
+    http_exception_handler as fastapi_http_exception_handler,
+)
+from fastapi.exception_handlers import (
+    request_validation_exception_handler as fastapi_validation_exception_handler,
+)
+from fastapi.exceptions import RequestValidationError
+
+from app.api.responses import error_response
+
+
+def _is_api_path(path: str) -> bool:
+    return path.startswith("/api/")
+
+
+def _status_code_to_error_code(status_code: int) -> str:
+    mapping = {
+        400: "bad_request",
+        401: "auth_required",
+        403: "forbidden",
+        404: "not_found",
+        409: "conflict",
+        422: "validation_error",
+        429: "rate_limited",
+        500: "internal_error",
+    }
+    return mapping.get(status_code, "error")
+
+
+class ApiException(Exception):
+    def __init__(
+        self,
+        *,
+        status_code: int,
+        code: str,
+        message: str,
+        details: Any | None = None,
+    ) -> None:
+        super().__init__(message)
+        self.status_code = status_code
+        self.code = code
+        self.message = message
+        self.details = details
+
+
+def register_api_exception_handlers(app: FastAPI) -> None:
+    @app.exception_handler(ApiException)
+    async def _handle_api_exception(request: Request, exc: ApiException):
+        return error_response(
+            request,
+            status_code=exc.status_code,
+            code=exc.code,
+            message=exc.message,
+            details=exc.details,
+        )
+
+    @app.exception_handler(HTTPException)
+    async def _handle_http_exception(request: Request, exc: HTTPException):
+        if not _is_api_path(request.url.path):
+            return await fastapi_http_exception_handler(request, exc)
+        return error_response(
+            request,
+            status_code=exc.status_code,
+            code=_status_code_to_error_code(exc.status_code),
+            message=str(exc.detail) if exc.detail is not None else "Request failed.",
+            details=exc.detail if isinstance(exc.detail, (dict, list)) else None,
+        )
+
+    @app.exception_handler(RequestValidationError)
+    async def _handle_validation_exception(request: Request, exc: RequestValidationError):
+        if not _is_api_path(request.url.path):
+            return await fastapi_validation_exception_handler(request, exc)
+        return error_response(
+            request,
+            status_code=422,
+            code="validation_error",
+            message="Request validation failed.",
+            details=exc.errors(),
+        )
+