douli8428 2016-08-19 05:31
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I am implementing a rest api where I send a json request body.

type Service struct {
    id int64 `db:"id" json:"id"`
    Name string `form:"name" db:"name" json:"name" binding:"required"`
    Servicetype string `form:"type"  db:"type" json:"type" binding:"required"`

func myHandler(c *gin.Context) {
    if c.BindJSON(&json) == nil {
    } else {
         fmt.Println("json binding error")

Servicetype is of type enum in my database. How can I have binding for that in my Service struct? I am able to bind the Name field as it is of type VARCHAR in database. But it fails to bind when I add Servicetype in the struct. I am using postgres as my database.

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  • dongou1970 2016-08-19 16:44

    Servicetype must implement Scanner and Valuer interfaces.

    Take a look on how std package does it for NullString

    // NullString represents a string that may be null.
    // NullString implements the Scanner interface so
    // it can be used as a scan destination:
    type NullString struct {
        String string
        Valid  bool // Valid is true if String is not NULL
    // Scan implements the Scanner interface.
    func (ns *NullString) Scan(value interface{}) error {
        if value == nil {
            ns.String, ns.Valid = "", false
            return nil
        ns.Valid = true
        return convertAssign(&ns.String, value)
    // Value implements the driver Valuer interface.
    func (ns NullString) Value() (driver.Value, error) {
        if !ns.Valid {
            return nil, nil
        return ns.String, nil
    本回答被题主选为最佳回答 , 对您是否有帮助呢?



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