golang常用库：字段参数验证库-validator

时间：2023-03-08 22:27:48

背景

在平常开发中，特别是在web应用开发中，为了验证输入字段的合法性，都会做一些验证操作。比如对用户提交的表单字段进行验证，或者对请求的API接口字段进行验证，验证字段的合法性，保证输入字段值的安全，防止用户的恶意请求。

一般的做法是用正则表达式，一个字段一个字段的进行验证。一个一个字段验证的话，写起来比较繁琐。那有没更好的方法，进行字段的合法性验证？有， 这就是下面要介绍的 validator 这个验证组件。

代码地址：

https://github.com/go-playground/validator

文档地址：

https://github.com/go-playground/validator/blob/master/README.md

安装

go get:

go get github.com/go-playground/validator/v10

在文件中引用validator包：

import "github.com/go-playground/validator/v10"

validator使用

文档：https://github.com/go-playground/validator/blob/master/README.md#examples

例子1：验证单个字段变量值

validation1.go

package main

import (

	"fmt"

	"github.com/go-playground/validator/v10"

)

func main() {

	validate := validator.New()

	var boolTest bool

	err := validate.Var(boolTest, "required")

	if err != nil {

		fmt.Println(err)

	}

	var stringTest string = ""

	err = validate.Var(stringTest, "required")

	if err != nil {

		fmt.Println(err)

	}

	var emailTest string = "test@126.com"

	err = validate.Var(emailTest, "email")

	if err != nil {

		fmt.Println(err)

	} else {

		fmt.Println("success") // 输出： success。 说明验证成功

	}

	emailTest2 := "test.126.com"

	errs := validate.Var(emailTest2, "required,email")

	if errs != nil {

		fmt.Println(errs) // 输出: Key: "" Error:Field validation for "" failed on the "email" tag。验证失败

	}

	fmt.Println("\r\nEnd!!")

}

运行输出：

go run simple1.go

Key: '' Error:Field validation for '' failed on the 'required' tag

Key: '' Error:Field validation for '' failed on the 'required' tag

success

Key: '' Error:Field validation for '' failed on the 'email' tag

End!!

例子2：验证结构体struct

from：struct validate

validation_struct.go，这个程序还列出了效验出错字段的一些信息，

package main

import (

	"fmt"

	"github.com/go-playground/validator/v10"

)

type User struct {

	FirstName string     `validate:"required"`

	LastName  string     `validate:"required"`

	Age       uint8      `validate:"gte=0,lte=130"`

	Email     string     `validate:"required,email"`

	Addresses []*Address `validate:"required,dive,required"`

}

type Address struct {

	Street string `validate:"required"`

	City   string `validate:"required"`

	Planet string `validate:"required"`

	Phone  string `validate:"required"`

}

func main() {

	address := &Address{

		Street: "Eavesdown Docks",

		Planet: "Persphone",

		Phone:  "none",

	}

	user := &User{

		FirstName: "Badger",

		LastName:  "Smith",

		Age:       135,

		Email:     "Badger.Smith@gmail.com",

		Addresses: []*Address{address},

	}

	validate := validator.New()

	err := validate.Struct(user)

	if err != nil {

		fmt.Println("=== error msg ====")

		fmt.Println(err)

		if _, ok := err.(*validator.InvalidValidationError); ok {

			fmt.Println(err)

			return

		}

		fmt.Println("\r\n=========== error field info ====================")

		for _, err := range err.(validator.ValidationErrors) {

           // 列出效验出错字段的信息

			fmt.Println("Namespace: ", err.Namespace())

			fmt.Println("Fild: ", err.Field())

			fmt.Println("StructNamespace: ", err.StructNamespace())

			fmt.Println("StructField: ", err.StructField())

			fmt.Println("Tag: ", err.Tag())

			fmt.Println("ActualTag: ", err.ActualTag())

			fmt.Println("Kind: ", err.Kind())

			fmt.Println("Type: ", err.Type())

			fmt.Println("Value: ", err.Value())

			fmt.Println("Param: ", err.Param())

			fmt.Println()

		}

		// from here you can create your own error messages in whatever language you wish

		return

	}

}

运行 输出：

$ go run validation_struct.go

=== error msg ====

Key: 'User.Age' Error:Field validation for 'Age' failed on the 'lte' tag

Key: 'User.Addresses[0].City' Error:Field validation for 'City' failed on the 'required' tag

=========== error field info ====================

Namespace: User.Age

Fild: Age

StructNamespace: User.Age

StructField: Age

Tag: lte

ActualTag: lte

Kind: uint8

Type: uint8

Value: 135

Param: 130

Namespace: User.Addresses[0].City

Fild: City

StructNamespace: User.Addresses[0].City

StructField: City

Tag: required

ActualTag: required

Kind: string

Type: string

Value:

Param:

还可以给字段加一些其他tag信息，方面form，json的解析，如下：

type User struct {

    FirstName string     `form:"firstname" json:"firstname" validate:"required"`

	LastName  string     `form:"lastname" json:"lastname" validate:"required"`

	Age       uint8      ` form:"age" json:"age"validate:"gte=0,lte=130"`

	Email     string     ` form:"email" json:"email" validate:"required,email"`

}

用户自定义函数验证

用户自定义函数验证字段是否合法，效验是否正确。

例子3: 通过字段tag自定义函数

validate.RegisterValidation

customer_tag.go：

package main

import (

	"fmt"

	"github.com/go-playground/validator/v10"

)

type User struct {

	Name string `form:"name" json:"name" validate:"required,CustomerValidation"` //注意：required和CustomerValidation之间不能有空格，否则panic。CustomerValidation：自定义tag-函数标签

	Age  uint8  ` form:"age" json:"age" validate:"gte=0,lte=80"`                 //注意：gte=0和lte=80之间不能有空格，否则panic

}

var validate *validator.Validate

func main() {

	validate = validator.New()

	validate.RegisterValidation("CustomerValidation", CustomerValidationFunc) //注册自定义函数，前一个参数是struct里tag自定义，后一个参数是自定义的函数

	user := &User{

		Name: "jimmy",

		Age:  86,

	}

	fmt.Println("first value: ", user)

	err := validate.Struct(user)

	if err != nil {

		fmt.Printf("Err(s):\n%+v\n", err)

	}

	user.Name = "tom"

	user.Age = 29

	fmt.Println("second value: ", user)

	err = validate.Struct(user)

	if err != nil {

		fmt.Printf("Err(s):\n%+v\n", err)

	}

}

// 自定义函数

func CustomerValidationFunc(f1 validator.FieldLevel) bool {

    // f1 包含了字段相关信息

    // f1.Field() 获取当前字段信息

    // f1.Param() 获取tag对应的参数

    // f1.FieldName() 获取字段名称

	return f1.Field().String() == "jimmy"

}

运行输出：

$ go run customer.go

first value: &{jimmy 86}

Err(s):

Key: 'User.Age' Error:Field validation for 'Age' failed on the 'lte' tag

second value: &{tom 29}

Err(s):

Key: 'User.Name' Error:Field validation for 'Name' failed on the 'CustomerValidation' tag

**注意：

上面代码user struct定义中 ，validate里的required和CustomerValidation之间不能有空格，否则运行时报panic错误：panic: Undefined validation function ' CustomerValidation' on field 'Name'

例子4：自定义函数-直接注册函数1

不通过字段tag自定义函数，直接注册函数。

RegisterStructValidation

https://github.com/go-playground/validator/blob/master/_examples/struct-level/main.go

customer1.go

package main

import (

	"fmt"

	"github.com/go-playground/validator/v10"

)

type User struct {

	FirstName      string `json:firstname`

	LastName       string `json:lastname`

	Age            uint8  `validate:"gte=0,lte=130"`

	Email          string `validate:"required,email"`

	FavouriteColor string `validate:"hexcolor|rgb|rgba"`

}

var validate *validator.Validate

func main() {

	validate = validator.New()

	validate.RegisterStructValidation(UserStructLevelValidation, User{})

	user := &User{

		FirstName:      "",

		LastName:       "",

		Age:            30,

		Email:          "TestFunc@126.com",

		FavouriteColor: "#000",

	}

	err := validate.Struct(user)

	if err != nil {

		fmt.Println(err)

	}

}

func UserStructLevelValidation(sl validator.StructLevel) {

	user := sl.Current().Interface().(User)

	if len(user.FirstName) == 0 && len(user.LastName) == 0 {

		sl.ReportError(user.FirstName, "FirstName", "firstname", "firstname", "")

		sl.ReportError(user.LastName, "LastName", "lastname", "lastname", "")

	}

}

运行输出：

$ go run customer1.go

Key: 'User.FirstName' Error:Field validation for 'FirstName' failed on the 'firstname' tag

Key: 'User.LastName' Error:Field validation for 'LastName' failed on the 'lastname' tag

例子5：自定义函数-直接注册函数2

RegisterCustomTypeFunc

https://github.com/go-playground/validator/blob/master/_examples/custom/main.go

validate.RegisterCustomTypeFunc：验证类型的自定义函数

customer2.go：

package main

import (

	"database/sql"

	"database/sql/driver"

	"fmt"

	"reflect"

	"github.com/go-playground/validator/v10"

)

type DbBackedUser struct {

	Name sql.NullString `validate:"required"`

	Age  sql.NullInt64  `validate:"required"`

}

var validate *validator.Validate

func main() {

	validate = validator.New()

	validate.RegisterCustomTypeFunc(ValidateValuer, sql.NullString{}, sql.NullInt64{}, sql.NullBool{}, sql.NullFloat64{})

	// build object for validation

	x := DbBackedUser{Name: sql.NullString{String: "", Valid: true}, Age: sql.NullInt64{Int64: 0, Valid: false}}

	err := validate.Struct(x)

	if err != nil {

		fmt.Printf("Err(s):\n%+v\n", err)

	}

}

func ValidateValuer(field reflect.Value) interface{} {

	if valuer, ok := field.Interface().(driver.Valuer); ok {

		val, err := valuer.Value()

		if err == nil {

			return val

		}

		// handle the error how you want

	}

	return nil

}

运行输出：

$ go run customer.go

Err(s):

Key: 'DbBackedUser.Name' Error:Field validation for 'Name' failed on the 'required' tag

Key: 'DbBackedUser.Age' Error:Field validation for 'Age' failed on the 'required' tag

注意，这个函数：

RegisterCustomTypeFunc，它上面有2行注释：

// RegisterCustomTypeFunc registers a CustomTypeFunc against a number of types

//

// NOTE: this method is not thread-safe it is intended that these all be registered prior to any validation

它是一个验证数据类型自定义函数，NOTE:这个方法不是线程安全的

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