utils/error_handler.py

from typing import Dict, Any, Optional
from fastapi import HTTPException
import logging

logger = logging.getLogger(__name__)

class StandardAPIResponse:
    """Standardized API response format"""
    
    @staticmethod
    def success(data: Any, message: str = "Operation successful", metadata: Optional[Dict] = None) -> Dict:
        """Create a successful response"""
        response = {
            "success": True,
            "data": data,
            "message": message
        }
        if metadata:
            response["metadata"] = metadata
        return response
    
    @staticmethod
    def error(error_message: str, status_code: int = 500, error_code: Optional[str] = None) -> Dict:
        """Create an error response"""
        response = {
            "success": False,
            "error": error_message,
            "status_code": status_code
        }
        if error_code:
            response["error_code"] = error_code
        return response

def handle_service_error(error: Exception, operation: str, user_context: Optional[str] = None) -> Dict:
    """
    Standardized error handling for service operations
    
    Args:
        error: The exception that occurred
        operation: Description of the operation that failed
        user_context: Additional context (e.g., user email)
    
    Returns:
        Standardized error response dictionary
    """
    error_msg = str(error)
    context_info = f" for {user_context}" if user_context else ""
    
    # Log the error
    logger.error(f"Error in {operation}{context_info}: {error_msg}")
    
    # Handle specific error types
    if isinstance(error, HTTPException):
        return StandardAPIResponse.error(
            error_message=error.detail,
            status_code=error.status_code
        )
    elif isinstance(error, ValueError):
        return StandardAPIResponse.error(
            error_message=f"Invalid input for {operation}: {error_msg}",
            status_code=400,
            error_code="INVALID_INPUT"
        )
    elif isinstance(error, ConnectionError):
        return StandardAPIResponse.error(
            error_message=f"Connection error during {operation}: {error_msg}",
            status_code=503,
            error_code="CONNECTION_ERROR"
        )
    else:
        return StandardAPIResponse.error(
            error_message=f"Unexpected error in {operation}: {error_msg}",
            status_code=500,
            error_code="INTERNAL_ERROR"
        )

def create_http_exception(error_response: Dict) -> HTTPException:
    """Convert standardized error response to HTTPException"""
    return HTTPException(
        status_code=error_response.get("status_code", 500),
        detail=error_response.get("error", "Internal server error")
    )