When the business requires more complex error code definitions, we can customize the implementation of business error codes by simply implementing the gcode.Code related interface.

Let’s look at an example.

Custom Error Codes

Define the basic business error code structure and implement the gcode.code interface.

type BizCode struct {
    code    int
    message string
    detail  BizCodeDetail
}
type BizCodeDetail struct {
    Code     string
    HttpCode int
}
func (c BizCode) BizDetail() BizCodeDetail {
    return c.detail
}
func (c BizCode) Code() int {
    return c.code
}
func (c BizCode) Message() string {
    return c.message
}
func (c BizCode) Detail() interface{} {
    return c.detail
}
func New(httpCode int, code string, message string) gcode.Code {
    return BizCode{
        code:    0,
        message: message,
        detail: BizCodeDetail{
            Code:     code,
            HttpCode: httpCode,
        },
    }
}

Define business error codes

var (
    CodeNil      = New(200, "OK", "")
    CodeNotFound = New(404, "Not Found", "Resource does not exist")
    CodeInternal = New(500, "Internal Error", "An error occurred internally")
    // ...
)

Usage in Middleware

func ResponseHandler(r *ghttp.Request) {
    r.Middleware.Next()
    // There's custom buffer content, it then exits current handler.
    if r.Response.BufferLength() > 0 {
        return
    }
    var (
        err  = r.GetError()
        res  = r.GetHandlerResponse()
        code = gerror.Code(err)
    )
    if code == gcode.CodeNil && err != nil {
        code = CodeInternal
    } else {
        code = CodeNil
    }
    if bizCode, ok := code.(BizCode); ok {
        r.Response.WriteStatus(bizCode.BizDetail().HttpCode)
    }
    r.Response.WriteJson(g.Map{
        `code`:    gcode.CodeOK.Code(),
        `message`: gcode.CodeOK.Message(),
        `data`:    res,
    })
}