Golang：验证字符串类型的结构字段是特定值之一

Question

Golang版本：1.18.3

验证器：github.com/go-playground/validator/v10

我想在加载到嵌套的结构数据结构中后验证传入的JSON有效负载。这是我传入的JSON有效负载，

{
  "name": "Duro",
  "gender": "MALE",
  "tier": 3,
  "mobileNumber": "0356874586",
  "address": {
    "city": "Tokyo",
    "street": "Shibaura St"
  },
  "children":[
    {
      "title": "Mr",
      "lastName": "Takayashi"
    }
  ],
  "isEmployed": false,
  "requestedAt": "2022-01-10T03:30:12.639Z"
}

这是我的用户。go文件，

package main

type User struct {
        Name                   string                     `validate:"required"`
        Gender                 string                     `validate:"required,oneof=MALE FEMALE"`
        Tier                   *uint8                     `validate:"required,eq=0|eq=1|eq=2|eq=3"`
        MobileNumber           string                     `validate:"required"`
        Email                  string
        Address                *Address  `validate:"required"`
        Children               []Child   `validate:"required,dive"`
        IsEmployed             *bool     `validate:"required"`
        PreferredContactMethod string    `validate:"oneof=EMAIL PHONE POST SMS"`
        RequestedAt            time.Time `validate:"required"`
    }
    type Address struct {
        City   string `validate:"required"`
        Street string `validate:"required"`
    }
    
    type Child struct {
        Title     string `validate:"required"`
        FirstName string
        LastName  string `validate:"required"`
    }

这是我的测试功能，

func TestUserPayload(t *testing.T) {
    validate := validator.New()
    var u User

    err := json.Unmarshal([]byte(jsonData), &u)
    if err != nil {
        panic(err)
    }

    err := validate.Struct(&u)
    if err != nil {
        t.Errorf("error %v", err)
    }

}

此测试失败而发生了错误，

error Key: 'User.PreferredContactMethod' Error:Field validation for 'PreferredContactMethod' failed on the 'oneof' tag

这发生了，因为GO将空字符串分配给user.preferredcontactmethod结构字段。由于preferredContactMethod不是必需的字段，因此当JSON有效负载没有它时，我不想看到此验证错误。 当JSON有效载荷没有PreferredContactMethod字段时，我如何避免此错误消息？

如果您有更好的替代方案来实现此验证，也很乐意听到他们的声音。

这是 go Playground中的代码

Answer 1

利用omitempty以及Oneof来使验证器库忽略空或未设置的值。

type User struct {
        Name                   string                     `validate:"required"`
        Gender                 string                     `validate:"required,oneof=MALE FEMALE"`
        Tier                   *uint8                     `validate:"required,eq=0|eq=1|eq=2|eq=3"`
        MobileNumber           string                     `validate:"required"`
        Email                  string
        Address                *Address  `validate:"required"`
        Children               []Child   `validate:"required,dive"`
        IsEmployed             *bool     `validate:"required"`
        PreferredContactMethod string    `validate:"omitempty,oneof=EMAIL PHONE POST SMS"`
        RequestedAt            time.Time `validate:"required"`
    }

Answer 2

使用 https://github.com/marrow16/valix （ https://pkg.go.dev/github.com/marrow16/valix ）可以通过以下内容来实现：

package main

import (
    "fmt"
    "time"

    "github.com/marrow16/valix"
)

type User struct {
    Name                   string    `json:"name" v8n:"required, notNull"`
    Gender                 string    `json:"gender" v8n:"required, notNull, &strtoken{['MALE','FEMALE']}"`
    Tier                   uint8     `json:"tier" v8n:"required, notNull, &mini{0}, &maxi{3}"`
    DateOfBirth            string    `json:"dateOfBirth" v8n:"notNull, &strisod"`
    MobileNumber           string    `json:"mobileNumber" v8n:"required, notNull, &strpatt{'^([0-9]{8,16})
 go playground： https://go.dev/play/p/3zrkzx97m-e 
披露：我是Valix的作者
}"`
    Email                  string    `json:"email" v8n:"notNull"`
    Address                Address   `json:"address" v8n:"required, notNull"`
    Children               []Child   `json:"children" v8n:"required, notNull"`
    IsEmployed             bool      `json:"isEmployed" v8n:"required"`
    PreferredContactMethod string    `json:"preferredContactMethod" v8n:"notNull, &strtoken{['EMAIL','PHONE','POST','SMS']}"`
    RequestedAt            time.Time `json:"requestedAt" v8n:"required, notNull, &strisodt"`
}
type Address struct {
    City   string `json:"city" v8n:"required, notNull"`
    Street string `json:"street" v8n:"required, notNull"`
}

type Child struct {
    Title     string `json:"title" v8n:"required, notNull"`
    FirstName string `json:"firstName" v8n:"notNull"`
    LastName  string `json:"lastName" v8n:"required, notNull"`
}

const jsonData = `{
  "name": "Duro",
  "gender": "MALE",
  "tier": 3,
  "dateOfBirth": "2000-01-13",
  "mobileNumber": "0356874586",
  "address": {
    "city": "Tokyo",
    "street": "Shibaura St"
  },
  "children":[
    {
      "title": "Mr",
      "lastName": "Takayashi"
    }
  ],
  "isEmployed": false,
  "requestedAt": "2022-01-10T03:30:12.639Z"
}`

var UserRequestValidator = valix.MustCompileValidatorFor(User{}, nil)

func main() {
    user := User{}

    ok, violations, _ := UserRequestValidator.ValidateStringInto(jsonData, &user)

    if ok {
        fmt.Println("Validation successful")
    } else {
        fmt.Println(fmt.Sprintf("Validation failed! (violations: %d)", len(violations)))
        for _, v := range violations {
            fmt.Printf("%s (property: '%s', path: '%s')\n", v.Message, v.Property, v.Path)
        }
    }
}

go playground： https://go.dev/play/p/3zrkzx97m-e

披露：我是Valix的作者