golang常用庫：欄位引數驗證庫-validator使用
阿新 • • 發佈：2020-10-16
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[golang常用庫：操作資料庫的orm框架-gorm基本使用](https://www.cnblogs.com/jiujuan/p/12676195.html)
[golang常用庫：欄位引數驗證庫-validator使用](https://www.cnblogs.com/jiujuan/p/13823864.html)
## 一、背景
在平常開發中，特別是在web應用開發中，為了驗證輸入欄位的合法性，都會做一些驗證操作。比如對使用者提交的表單欄位進行驗證，或者對請求的API介面欄位進行驗證，驗證欄位的合法性，保證輸入欄位值的安全，防止使用者的惡意請求。
一般的做法是用正則表示式，一個欄位一個欄位的進行驗證。一個一個欄位驗證的話，寫起來比較繁瑣。那有沒更好的方法，進行欄位的合法性驗證？有， 這就是下面要介紹的 [validator](https://github.com/go-playground/validator) 這個驗證元件。
程式碼地址：
[https://github.com/go-playground/validator](https://github.com/go-playground/validator)
文件地址：
[https://github.com/go-playground/validator/blob/master/README.md](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](https://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"`，逗號那裡不能有空格，否則panic
- 橫線( `-` )：跳過該欄位不驗證
- 豎線( `|` )：使用多個驗證標記，但是隻需滿足其中一個即可
- required：表示該欄位值必輸設定，且不能為預設值
- omitempty：如果欄位未設定，則忽略它
### 範圍比較驗證
>doc: https://github.com/go-playground/validator/blob/master/README.md#comparisons
範圍驗證: 切片、陣列和map、字串，驗證其長度；數值，驗證大小範圍
- lte：小於等於引數值，`validate:"lte=3"` (小於等於3)
- gte：大於等於引數值，`validate:"lte=0,gte=120"` (大於等於0小於等於120)
- lt：小於引數值，`validate:"lt=3"` (小於3)
- gt：大於引數值，`validate:"lt=0,gt=120"` (大於0小於120)
- len：等於引數值，`validate:"len=2"`
- max：大於等於引數值，`validate:"max=2"` (大於等於2)
- min：小於等於引數值，`validate:"min=2,max=10"` (大於等於2小於等於10)
- ne：不等於，`validate:"ne=2"` (不等於2)
- oneof：只能是列舉出的值其中一個，這些值必須是數值或字串，以空格分隔，如果字串中有空格，將字串用單引號包圍，`validate:"oneof=red green"`
例子：
```go
type User struct {
Name string `json:"name" validate:"min=0,max=35"`
Age unit8 `json:"age" validate:"lte=0,gte=90"`
}
```
更多功能請參看文件 [validator comparisons doc](https://github.com/go-playground/validator/blob/master/README.md#comparisons)
### 字串驗證
>doc: https://github.com/go-playground/validator/blob/master/README.md#strings
- contains：包含引數子串，`validate:"contains=tom"` (欄位的字串值包含tom)
- excludes：包含引數子串，`validate:"excludes=tom"` (欄位的字串值不包含tom)
- startswith：以引數子串為字首，`validate:"startswith=golang"`
- endswith：以引數子串為字尾，`validate:"startswith=world"`
例子：
```go
type User struct {
Name string `validate:"contains=tom"`
Age int `validate:"min=1"`
}
```
更多功能請參看文件 [validator strings doc](https://github.com/go-playground/validator/blob/master/README.md#strings)
### 欄位驗證
> doc: https://github.com/go-playground/validator/blob/master/README.md#fields
- eqcsfield：跨不同結構體欄位驗證，比如說 Struct1 Filed1，與結構體Struct2 Field2相等，
```go
type Struct1 struct {
Field1 string `validate:eqcsfield=Struct2.Field2`
Struct2 struct {
Field2 string
}
}
```
- necsfield：跨不同結構體欄位不相等
- eqfield：同一結構體欄位驗證相等，最常見的就是輸入2次密碼驗證
```go
type User struct {
Name string `validate:"lte=4"`
Age int `validate:"min=20"`
Password string `validate:"min=10"`
Password2 string `validate:"eqfield=Password"`
}
```
- nefield：同一結構體欄位驗證不相等
```go
type User struct {
Name string `validate:"lte=4"`
Age int `validate:"min=20"`
Password string `validate:"min=10,nefield=Name"`
}
```
- gtefield：大於等於同一結構體欄位，`validate:"gtefiled=Field2"`
- ltefield：小於等於同一結構體欄位
更多功能請參看文件：[validator Fields DOC](https://github.com/go-playground/validator/blob/master/README.md#fields)
### 網路驗證
>doc: https://github.com/go-playground/validator/blob/master/README.md#network
- ip：欄位值是否包含有效的IP地址，`validate:"ip"`
- ipv4：欄位值是否包含有效的ipv4地址，`validate:"ipv4"`
- ipv6：欄位值是否包含有效的ipv6地址，`validate:"ipv6"`
- uri：欄位值是否包含有效的uri，`validate:"uri"`
- url：欄位值是否包含有效的uri，`validate:"url"`
更多功能請參看文件：[validator network DOC](https://github.com/go-playground/validator/blob/master/README.md#network)
### Format
>doc: https://github.com/go-playground/validator/blob/master/README.md#format
- base64：欄位值是否包含有效的base64值
更多功能請參看文件 [validator strings doc](https://github.com/go-playground/validator/blob/master/README.md#strings)
### 其他
>請參看文件: [https://github.com/go-playground/validator/blob/master/README.md#other](https://github.com/go-playground/validator/blob/master/README.md#other)
## 三、安裝
go get:
>go get github.com/go-playground/validator/v10
在檔案中引用validator包：
> import "github.com/go-playground/validator/v10"
## 四、validator使用
>文件：https://github.com/go-playground/validator/blob/master/README.md#examples
### 例子1：驗證單個欄位變數值
validation1.go
```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") // 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!!")
}
```
執行輸出：
>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](https://github.com/go-playground/validator/blob/master/_examples/simple/main.go)
validation_struct.go，這個程式還列出了效驗出錯欄位的一些資訊，
```go
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) {
// 列出效驗出錯欄位的資訊
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
}
}
```
執行 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:
還可以給欄位加一些其他tag資訊，方面form，json的解析，如下：
```go
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"`
}
```
### 使用者自定義函式驗證
使用者自定義函式驗證欄位是否合法，效驗是否正確。
### 例子3: 通過欄位tag自定義函式
##### validate.RegisterValidation
customer_tag.go：
```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-函式標籤
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) //註冊自定義函式，前一個引數是struct裡tag自定義，後一個引數是自定義的函式
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)
}
}
// 自定義函式
func CustomerValidationFunc(f1 validator.FieldLevel) bool {
// f1 包含了欄位相關資訊
// f1.Field() 獲取當前欄位資訊
// f1.Param() 獲取tag對應的引數
// f1.FieldName() 獲取欄位名稱
return f1.Field().String() == "jimmy"
}
```
執行輸出：
>$ 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*