Golang错误返回封装与统一处理示例

type APIError struct {
    Code    int    `json:"code"`
    Message string `json:"message"`
    Detail  string `json:"detail,omitempty"`
}
func (e *APIError) Error() string {
return fmt.Sprintf("error %d: %s", e.Code, e.Message)
}

var (
    ErrInvalidRequest = &APIError{Code: 400, Message: "无效请求"}
    ErrUnauthorized   = &APIError{Code: 401, Message: "未授权访问"}
    ErrNotFound       = &APIError{Code: 404, Message: "资源不存在"}
    ErrInternalServer = &APIError{Code: 500, Message: "服务器内部错误"}
)
func NewValidationError(msg string) *APIError {
return &APIError{Code: 400, Message: "参数校验失败", Detail: msg}
}
func NewNotFoundError(resource string) *APIError {
return &APIError{
Code:    404,
Message: "资源未找到",
Detail:  resource,
}
}

func ErrorHandler() gin.HandlerFunc {
    return func(c *gin.Context) {
        c.Next()
    if len(c.Errors) > 0 {
        err := c.Errors[0].Err
        var apiErr *APIError

        if errors.As(err, &apiErr) {
            c.JSON(apiErr.Code, apiErr)
        } else {
            // 非预期错误统一返回500
            unknownErr := ErrInternalServer
            unknownErr.Detail = err.Error()
            c.JSON(500, unknownErr)
        }
    }
}
}

func GetUser(c *gin.Context) {
    id := c.Param("id")
    if id == "" {
        c.Error(NewValidationError("缺少用户ID"))
        return
    }
user, err := userService.FindByID(id)
if err != nil {
    if errors.Is(err, sql.ErrNoRows) {
        c.Error(NewNotFoundError("User"))
        return
    }
    c.Error(ErrInternalServer)
    return
}

c.JSON(200, user)
}