s2f/backend/app/core/error_handlers.py

from typing import Any

from fastapi import HTTPException, Request, status
from fastapi.exceptions import RequestValidationError
from fastapi.responses import JSONResponse
from sqlalchemy.exc import IntegrityError

from app.core.exceptions import (
    BusinessException,
    ExternalServiceException,
    ForbiddenException,
    NotFoundException,
    S2FException,
    UnauthorizedException,
    ValidationException,
)
from app.core.logging import logger


def create_error_response(
    code: str,
    message: str,
    details: Any = None,
    status_code: int = status.HTTP_500_INTERNAL_SERVER_ERROR,
) -> JSONResponse:
    """
    创建统一错误响应
    
    Args:
        code: 错误代码
        message: 错误消息
        details: 错误详情
        status_code: HTTP 状态码
        
    Returns:
        JSON 响应
    """
    error_data = {
        "error": {
            "code": code,
            "message": message,
        }
    }
    
    if details:
        error_data["error"]["details"] = details
    
    return JSONResponse(
        status_code=status_code,
        content=error_data,
    )


async def s2f_exception_handler(request: Request, exc: S2FException) -> JSONResponse:
    """
    处理自定义业务异常
    
    Args:
        request: 请求对象
        exc: 异常对象
        
    Returns:
        JSON 响应
    """
    logger.warning(
        "business_exception",
        code=exc.code,
        message=exc.message,
        details=exc.details,
        path=request.url.path,
    )
    
    # 根据异常类型映射 HTTP 状态码
    status_code_map = {
        NotFoundException: status.HTTP_404_NOT_FOUND,
        UnauthorizedException: status.HTTP_401_UNAUTHORIZED,
        ForbiddenException: status.HTTP_403_FORBIDDEN,
        ValidationException: status.HTTP_422_UNPROCESSABLE_ENTITY,
        BusinessException: status.HTTP_400_BAD_REQUEST,
        ExternalServiceException: status.HTTP_503_SERVICE_UNAVAILABLE,
    }
    
    status_code = status_code_map.get(type(exc), status.HTTP_500_INTERNAL_SERVER_ERROR)
    
    return create_error_response(
        code=exc.code,
        message=exc.message,
        details=exc.details,
        status_code=status_code,
    )


async def validation_exception_handler(request: Request, exc: RequestValidationError) -> JSONResponse:
    """
    处理请求验证异常
    
    Args:
        request: 请求对象
        exc: 验证异常
        
    Returns:
        JSON 响应
    """
    logger.warning(
        "validation_error",
        errors=exc.errors(),
        body=exc.body,
        path=request.url.path,
    )
    
    return create_error_response(
        code="VALIDATION_ERROR",
        message="请求参数验证失败",
        details={"errors": exc.errors()},
        status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
    )


async def http_exception_handler(request: Request, exc: HTTPException) -> JSONResponse:
    """
    处理 HTTP 异常
    
    Args:
        request: 请求对象
        exc: HTTP 异常
        
    Returns:
        JSON 响应
    """
    logger.warning(
        "http_exception",
        status_code=exc.status_code,
        detail=exc.detail,
        path=request.url.path,
    )
    
    return create_error_response(
        code="HTTP_ERROR",
        message=str(exc.detail),
        status_code=exc.status_code,
    )


async def integrity_error_handler(request: Request, exc: IntegrityError) -> JSONResponse:
    """
    处理数据库完整性错误
    
    Args:
        request: 请求对象
        exc: 完整性错误
        
    Returns:
        JSON 响应
    """
    logger.error(
        "database_integrity_error",
        error=str(exc),
        path=request.url.path,
    )
    
    return create_error_response(
        code="DATABASE_ERROR",
        message="数据库操作失败，可能存在重复或约束冲突",
        status_code=status.HTTP_409_CONFLICT,
    )


async def generic_exception_handler(request: Request, exc: Exception) -> JSONResponse:
    """
    处理未捕获的异常
    
    Args:
        request: 请求对象
        exc: 异常对象
        
    Returns:
        JSON 响应
    """
    logger.error(
        "unhandled_exception",
        error=str(exc),
        error_type=type(exc).__name__,
        path=request.url.path,
        exc_info=True,
    )
    
    return create_error_response(
        code="INTERNAL_ERROR",
        message="服务器内部错误",
        status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
    )