init: added template

src/backend/api/v1/handlers.py

@@ -0,0 +1,186 @@
+import logging
+from collections.abc import Callable
+from http import HTTPStatus as status
+from typing import Any
+
+import django.core.exceptions
+import django.http
+import ninja.errors
+from django.http import HttpRequest, HttpResponse
+from ninja import NinjaAPI
+
+from api.v1.schemas import ApiError, ValidationError
+from config.errors import ConflictError, ForbiddenError
+from config.utils import build_error_payload
+
+logger = logging.getLogger("django")
+
+
+def create_error_response(
+    request: HttpRequest,
+    code: str,
+    message: str,
+    http_status: int,
+    router: NinjaAPI,
+    details: dict[str, Any] | None = None,
+) -> HttpResponse:
+    payload = build_error_payload(
+        request=request,
+        code=code,
+        message=message,
+        details=details,
+    )
+    error_data = ApiError.model_validate(payload)
+    return router.create_response(request, error_data, status=http_status)
+
+
+def handle_validation_error(
+    request: HttpRequest,
+    exc: ninja.errors.ValidationError,
+    router: NinjaAPI,
+) -> HttpResponse:
+    field_errors_data: list[dict[str, Any]] = []
+    for error in exc.errors:
+        loc = error.get("loc", [])
+        field = ".".join(map(str, loc)) if loc else "non_field_error"
+        field_errors_data.append(
+            {
+                "field": field,
+                "issue": error.get("msg", "Unknown error"),
+                "rejectedValue": error.get("input"),
+            }
+        )
+
+    payload = build_error_payload(
+        request=request,
+        code="VALIDATION_FAILED",
+        message="Validation failed",
+        field_errors=field_errors_data,
+    )
+    error_data = ValidationError.model_validate(payload)
+    return router.create_response(
+        request, error_data, status=status.UNPROCESSABLE_ENTITY
+    )
+
+
+def handle_django_validation_error(
+    request: HttpRequest,
+    exc: django.core.exceptions.ValidationError,
+    router: NinjaAPI,
+    code: str = "VALIDATION_FAILED",
+    http_status: int = status.UNPROCESSABLE_ENTITY,
+) -> HttpResponse:
+    field_errors_data: list[dict[str, Any]] = []
+    if hasattr(exc, "error_dict"):
+        for field, errors in exc.error_dict.items():
+            field_errors_data.extend(
+                {
+                    "field": field,
+                    "issue": str(error.message),
+                    "rejectedValue": None,
+                }
+                for error in errors
+            )
+    else:
+        field_errors_data.extend(
+            {
+                "field": "non_field_error",
+                "issue": str(error.message),
+                "rejectedValue": None,
+            }
+            for error in exc.error_list
+        )
+
+    payload = build_error_payload(
+        request=request,
+        code=code,
+        message="Validation failed"
+        if code == "VALIDATION_FAILED"
+        else "Conflict",
+        field_errors=field_errors_data,
+    )
+    error_data = ValidationError.model_validate(payload)
+    return router.create_response(request, error_data, status=http_status)
+
+
+def handle_authentication_error(
+    request: HttpRequest,
+    exc: ninja.errors.AuthenticationError,
+    router: NinjaAPI,
+) -> HttpResponse:
+    return create_error_response(
+        request,
+        code="UNAUTHENTICATED",
+        message="Authentication required",
+        http_status=status.UNAUTHORIZED,
+        router=router,
+    )
+
+
+def handle_forbidden_error(
+    request: HttpRequest,
+    exc: ForbiddenError,
+    router: NinjaAPI,
+) -> HttpResponse:
+    return create_error_response(
+        request,
+        code="FORBIDDEN",
+        message=exc.message,
+        http_status=status.FORBIDDEN,
+        router=router,
+    )
+
+
+def handle_not_found_error(
+    request: HttpRequest,
+    exc: Exception,
+    router: NinjaAPI,
+) -> HttpResponse:
+    return create_error_response(
+        request,
+        code="NOT_FOUND",
+        message="Resource not found",
+        http_status=status.NOT_FOUND,
+        router=router,
+    )
+
+
+def handle_conflict_error(
+    request: HttpRequest,
+    exc: ConflictError,
+    router: NinjaAPI,
+) -> HttpResponse:
+    return handle_django_validation_error(
+        request,
+        exc.validation_error,
+        router,
+        code="CONFLICT",
+        http_status=status.CONFLICT,
+    )
+
+
+def handle_unknown_exception(
+    request: HttpRequest,
+    exc: Exception,
+    router: NinjaAPI,
+) -> HttpResponse:
+    logger.error("Internal server error: %s", exc, exc_info=True)  # noqa: LOG014
+
+    return create_error_response(
+        request,
+        code="INTERNAL_SERVER_ERROR",
+        message="An unexpected error occurred",
+        http_status=status.INTERNAL_SERVER_ERROR,
+        router=router,
+    )
+
+
+exception_handlers: list[tuple[Any, Callable[..., Any]]] = [
+    (ninja.errors.ValidationError, handle_validation_error),
+    (django.core.exceptions.ValidationError, handle_django_validation_error),
+    (ninja.errors.AuthenticationError, handle_authentication_error),
+    (ForbiddenError, handle_forbidden_error),
+    (django.http.Http404, handle_not_found_error),
+    (ConflictError, handle_conflict_error),
+    (Exception, handle_unknown_exception),
+]

src/backend/api/v1/router.py

@@ -0,0 +1,43 @@
+from functools import partial
+from typing import Any, override
+
+import orjson
+from django.http import HttpRequest
+from ninja import NinjaAPI, Schema
+from ninja.renderers import BaseRenderer
+
+from api.v1 import handlers
+
+
+class ORJSONRenderer(BaseRenderer):
+    media_type: str | None = "application/json"
+
+    @override
+    def render(
+        self, request: HttpRequest, data: Any, *, response_status: int
+    ) -> Any:
+        return orjson.dumps(data, default=self.default)
+
+    def default(self, obj: Any) -> Any:
+        if isinstance(obj, Schema):
+            return obj.model_dump(by_alias=True)
+        raise TypeError
+
+
+router = NinjaAPI(
+    title="Lotty API",
+    version="1",
+    description="API docs for Lotty A/B platform",
+    openapi_url="/docs/openapi.json",
+    renderer=ORJSONRenderer(),
+)
+
+
+# router.add_router(
+#     "health",
+#     health_router,
+# )
+
+
+for exception, handler in handlers.exception_handlers:
+    router.add_exception_handler(exception, partial(handler, router=router))

src/backend/api/v1/schemas.py

@@ -0,0 +1,33 @@
+from datetime import datetime
+from typing import Any
+
+from ninja import Schema
+from pydantic import ConfigDict, Field
+
+
+class FieldError(Schema):
+    model_config = ConfigDict(populate_by_name=True)
+
+    field: str = Field(
+        ...,
+        description="Field name with error (can be nested)",
+    )
+    issue: str = Field(..., description="Problem description")
+    rejected_value: Any = Field(
+        None, alias="rejectedValue", description="Value that failed validation"
+    )
+
+
+class ApiError(Schema):
+    model_config = ConfigDict(populate_by_name=True)
+
+    code: str
+    message: str
+    trace_id: str = Field(..., alias="traceId")
+    timestamp: datetime
+    path: str
+    details: dict[str, Any] | None = None
+
+
+class ValidationError(ApiError):
+    field_errors: list[FieldError] = Field(..., alias="fieldErrors")