golang常用库之字段参数验证库-validator使用详解

golang常用库:gorilla/mux-http路由库使用
golang常用库:配置文件解析库-viper使用
golang常用库:操作数据库的orm框架-gorm基本使用
golang常用库:字段参数验证库-validator使用

一、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

二、功能介绍

这个验证包 github.com/go-playground/validator 验证功能非常多。

标记之间特殊符号说明

  • 逗号( , ):把多个验证标记隔开。注意:隔开逗号之间不能有空格, validate:"lt=0,gt=100",逗号那里不能有空格,否则panic
  • 横线( - ):跳过该字段不验证
  • 竖线( | ):使用多个验证标记,但是只需满足其中一个即可
  • required:表示该字段值必输设置,且不能为默认值
  • omitempty:如果字段未设置,则忽略它

范围比较验证

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

范围验证: 切片、数组和map、字符串,验证其长度;数值,验证大小范围

  • lte:小于等于参数值,validate:"lte=3" (小于等于3)
  • gte:大于等于参数值,validate:"lte=0,gte=120" (大于等于0小于等于120)
  • lt:小于参数值,validate:"lt=3" (小于3)
  • gt:大于参数值,validate:"lt=0,gt=120" (大于0小于120)
  • len:等于参数值,validate:"len=2"
  • max:大于等于参数值,validate:"max=2" (大于等于2)
  • min:小于等于参数值,validate:"min=2,max=10" (大于等于2小于等于10)
  • ne:不等于,validate:"ne=2" (不等于2)
  • oneof:只能是列举出的值其中一个,这些值必须是数值或字符串,以空格分隔,如果字符串中有空格,将字符串用单引号包围,validate:"oneof=red green"

例子:

type User struct {
 Name string `json:"name" validate:"min=0,max=35"`
 Age unit8 `json:"age" validate:"lte=0,gte=90"`
}

更多功能请参看文档 validator comparisons doc

字符串验证

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

  • contains:包含参数子串,validate:"contains=tom" (字段的字符串值包含tom)
  • excludes:包含参数子串,validate:"excludes=tom" (字段的字符串值不包含tom)
  • startswith:以参数子串为前缀,validate:"startswith=golang"
  • endswith:以参数子串为后缀,validate:"startswith=world"

例子:

type User struct { 
 Name string `validate:"contains=tom"` 
 Age int `validate:"min=1"`
}

更多功能请参看文档 validator strings doc

字段验证

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

eqcsfield:跨不同结构体字段验证,比如说 Struct1 Filed1,与结构体Struct2 Field2相等,

type Struct1 struct {
 Field1 string `validate:eqcsfield=Struct2.Field2`
 Struct2 struct {
 Field2 string 
 }
}
  • necsfield:跨不同结构体字段不相等
  • eqfield:同一结构体字段验证相等,最常见的就是输入2次密码验证
type User struct { 
 Name string `validate:"lte=4"` 
 Age int `validate:"min=20"` 
 Password string `validate:"min=10"`
 Password2 string `validate:"eqfield=Password"`
}

nefield:同一结构体字段验证不相等

type User struct {
 Name string `validate:"lte=4"` 
 Age int `validate:"min=20"` 
 Password string `validate:"min=10,nefield=Name"`
}
  • gtefield:大于等于同一结构体字段,validate:"gtefiled=Field2"
  • ltefield:小于等于同一结构体字段

更多功能请参看文档:validator Fields DOC

网络验证

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

  • ip:字段值是否包含有效的IP地址,validate:"ip"
  • ipv4:字段值是否包含有效的ipv4地址,validate:"ipv4"
  • ipv6:字段值是否包含有效的ipv6地址,validate:"ipv6"
  • uri:字段值是否包含有效的uri,validate:"uri"
  • url:字段值是否包含有效的uri,validate:"url"

更多功能请参看文档:validator network DOC

Format

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

base64:字段值是否包含有效的base64值

更多功能请参看文档 validator strings doc

其他

请参看文档: https://github.com/go-playground/validator/blob/master/README.md#other

三、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"

四、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 = "[email protected]"
	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: "[email protected]",
		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: "[email protected]",
		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

五、参考

https://github.com/go-playground/validator/blob/master/README.mdhttps://github.com/go-playground/validator/tree/master/_examples

总结

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