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golang常用庫：gorilla/mux-http路由庫使用
golang常用庫：配置文件解析庫-viper使用
golang常用庫：操作數據庫的orm框架-gorm基本使用
golang常用庫：字段參數驗證庫-validator使用

一、背景

在平常開發中，特別是在web應用開發中，為了驗證輸入字段的合法性，都會做一些驗證操作。比如對用戶提交的表單字段進行驗證，或者對請求的API接口字段進行驗證，驗證字段的合法性，保證輸入字段值的安全，防止用戶的惡意請求。

一般的做法是用正則表達式，一個字段一個字段的進行驗證。一個一個字段驗證的話，寫起來比較繁瑣。那有沒更好的方法，進行字段的合法性驗證？有，這就是下面要介紹的 validator 這個驗證組件。

代碼地址：
https://github.com/go-playground/validator

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

二、功能介紹

這個驗證包 github.com/go-playground/validator 驗證功能非常多。

標記之間特殊符號說明

逗號( , )：把多個驗證標記隔開。注意：隔開逗號之間不能有空格, validate:"lt=0,gt=100"，逗號那里不能有空格，否則panic
橫線( - )：跳過該字段不驗證
豎線( | )：使用多個驗證標記，但是只需滿足其中一個即可
required：表示該字段值必輸設置，且不能為默認值
omitempty：如果字段未設置，則忽略它

范圍比較驗證

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

范圍驗證: 切片、數組和map、字符串，驗證其長度；數值，驗證大小范圍

lte：小于等于參數值，validate:"lte=3" (小于等于3)
gte：大于等于參數值，validate:"lte=0,gte=120" (大于等于0小于等于120)
lt：小于參數值，validate:"lt=3" (小于3)
gt：大于參數值，validate:"lt=0,gt=120" (大于0小于120)
len：等于參數值，validate:"len=2"
max：大于等于參數值，validate:"max=2" (大于等于2)
min：小于等于參數值，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：只能是列舉出的值其中一個，這些值必須是數值或字符串，以空格分隔，如果字符串中有空格，將字符串用單引號包圍，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"`
}

更多功能請參看文檔 validator comparisons doc

字符串驗證

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

contains：包含參數子串，validate:"contains=tom" (字段的字符串值包含tom)
excludes：包含參數子串，validate:"excludes=tom" (字段的字符串值不包含tom)
startswith：以參數子串為前綴，validate:"startswith=golang"
endswith：以參數子串為后綴，validate:"startswith=world"

例子：

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

更多功能請參看文檔 validator strings doc

字段驗證

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

eqcsfield：跨不同結構體字段驗證，比如說 Struct1 Filed1，與結構體Struct2 Field2相等，

type Struct1 struct {
 Field1 string `validate:eqcsfield=Struct2.Field2`
 Struct2 struct {
 Field2 string 
 }
}

necsfield：跨不同結構體字段不相等
eqfield：同一結構體字段驗證相等，最常見的就是輸入2次密碼驗證

type User struct { 
 Name string `validate:"lte=4"` 
 Age int `validate:"min=20"` 
 Password string `validate:"min=10"`
 Password2 string `validate:"eqfield=Password"`
}

nefield：同一結構體字段驗證不相等

type User struct {
 Name string `validate:"lte=4"` 
 Age int `validate:"min=20"` 
 Password string `validate:"min=10,nefield=Name"`
}

gtefield：大于等于同一結構體字段，validate:"gtefiled=Field2"
ltefield：小于等于同一結構體字段

更多功能請參看文檔：validator Fields DOC

網絡驗證

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"

更多功能請參看文檔：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

更多功能請參看文檔 validator strings doc

其他

請參看文檔: https://github.com/go-playground/validator/blob/master/README.md#other

三、安裝

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

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

例子1：驗證單個字段變量值

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") // 輸出： success。 說明驗證成功
	}

	emailTest2 := "test.126.com"
	errs := validate.Var(emailTest2, "required,email")
	if errs != nil {
		fmt.Println(errs) // 輸出: Key: "" Error:Field validation for "" failed on the "email" tag。驗證失敗
	}

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

運行輸出：

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：驗證結構體struct

from：struct validate

validation_struct.go，這個程序還列出了效驗出錯字段的一些信息，

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) {
 // 列出效驗出錯字段的信息
			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
	}
}

運行輸出：

$ 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:

還可以給字段加一些其他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"`
}

用戶自定義函數驗證

用戶自定義函數驗證字段是否合法，效驗是否正確。

例子3: 通過字段tag自定義函數

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之間不能有空格，否則panic。CustomerValidation：自定義tag-函數標簽
	Age uint8 ` form:"age" json:"age" validate:"gte=0,lte=80"` //注意：gte=0和lte=80之間不能有空格，否則panic
}

var validate *validator.Validate

func main() {
	validate = validator.New()
	validate.RegisterValidation("CustomerValidation", CustomerValidationFunc) //注冊自定義函數，前一個參數是struct里tag自定義，后一個參數是自定義的函數

	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)
	}
}

// 自定義函數
func CustomerValidationFunc(f1 validator.FieldLevel) bool {
 // f1 包含了字段相關信息
 // f1.Field() 獲取當前字段信息
 // f1.Param() 獲取tag對應的參數
 // f1.FieldName() 獲取字段名稱
 
	return f1.Field().String() == "jimmy"
}

運行輸出：

$ 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：

上面代碼user struct定義中，validate里的required和CustomerValidation之間不能有空格，否則運行時報panic錯誤：panic: Undefined validation function ' CustomerValidation' on field 'Name'

例子4：自定義函數-直接注冊函數1

不通過字段tag自定義函數，直接注冊函數。

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", "")
	}
}

運行輸出：

$ 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：自定義函數-直接注冊函數2

RegisterCustomTypeFunc

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

validate.RegisterCustomTypeFunc：驗證類型的自定義函數

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
}

運行輸出：

$ 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，這個函數：
RegisterCustomTypeFunc，它上面有2行注釋：

// 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

它是一個驗證數據類型自定義函數，NOTE:這個方法不是線程安全的

五、參考

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

總結

到此這篇關于golang常用庫：字段參數驗證庫-validator使用的文章就介紹到這了,更多相關golang字段參數驗證庫validator內容請搜索腳本之家以前的文章或繼續瀏覽下面的相關文章希望大家以后多多支持腳本之家！

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