add api exception handler (#74)

* try to add exception handler

* improve server error test

* fix lint

* add build_uri util

* fix header file path

---------

Co-authored-by: Dmitry Afanasyev <afanasiev@litres.ru>

bot_microservice/api/base_schemas.py

@@ -0,0 +1,27 @@
+from typing import Any
+
+from fastapi import status as status_code
+from pydantic import BaseModel, Field
+
+
+class BaseError(BaseModel):
+    """Error response as defined in
+    https://datatracker.ietf.org/doc/html/rfc7807.
+
+    One difference is that the member "type" is not a URI
+    """
+
+    type: str | None = Field(title="The name of the class of the error")
+    title: str | None = Field(
+        title="A short, human-readable summary of the problem that does not change from occurence to occurence",
+    )
+    detail: str | None = Field(
+        default=None, title="А human-readable explanation specific to this occurrence of the problem"
+    )
+    instance: Any | None = Field(default=None, title="Identifier for this specific occurrence of the problem")
+
+
+class BaseResponse(BaseModel):
+    status: int = Field(..., title="Status code of request.", example=status_code.HTTP_200_OK)  # type: ignore[call-arg]
+    error: dict[Any, Any] | BaseError | None = Field(default=None, title="Errors")
+    payload: Any | None = Field(default_factory=dict, title="Payload data.")

bot_microservice/api/exceptions.py

@@ -1,2 +1,34 @@
+from fastapi.responses import ORJSONResponse
+from starlette.requests import Request
+
+from api.base_schemas import BaseError, BaseResponse
+
+
 class BaseAPIException(Exception):
     pass
+
+
+class InternalServerError(BaseError):
+    pass
+
+
+class InternalServerErrorResponse(BaseResponse):
+    error: InternalServerError
+
+    class Config:
+        json_schema_extra = {
+            "example": {
+                "status": 500,
+                "error": {
+                    "type": "InternalServerError",
+                    "title": "Server encountered an unexpected error that prevented it from fulfilling the request",
+                    "detail": "error when adding send message",
+                },
+            },
+        }
+
+
+async def internal_server_error_handler(_request: Request, _exception: Exception) -> ORJSONResponse:
+    error = InternalServerError(title="Something went wrong!", type="InternalServerError")
+    response = InternalServerErrorResponse(status=500, error=error).model_dump(exclude_unset=True)
+    return ORJSONResponse(status_code=500, content=response)