自定义验证

都在代码里自己看吧

package main

import (
    "fmt"
    "net/http"

    "github.com/gin-gonic/gin"
    "gopkg.in/go-playground/validator.v9"
)

/*
    对绑定解析到结构体上的参数，自定义验证功能
    比如我们需要对URL的接受参数进行判断，判断用户名是否为root如果是root通过否则返回false
*/
type Login struct {
    User    string `uri:"user" validate:"checkName"`
    Pssword string `uri:"password"`
}

// 自定义验证函数
func checkName(fl validator.FieldLevel) bool {
    if fl.Field().String() != "root" {
        return false
    }
    return true
}
func main() {
    r := gin.Default()
    validate := validator.New()
    r.GET("/:user/:password", func(c *gin.Context) {
        var login Login
         //注册自定义函数，与struct tag关联起来
        err := validate.RegisterValidation("checkName", checkName)
        if err := c.ShouldBindUri(&login); err != nil {
            c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
            return
        }
        err = validate.Struct(login)
        if err != nil {
            for _, err := range err.(validator.ValidationErrors) {
                fmt.Println(err)
            }
            return
        }
        fmt.Println("success")
    })
    r.Run()
}

示例2：

package main

import (
    "net/http"
    "reflect"
    "time"

    "github.com/gin-gonic/gin"
    "github.com/gin-gonic/gin/binding"
    "gopkg.in/go-playground/validator.v8"
)

// Booking contains binded and validated data.
type Booking struct {
    //定义一个预约的时间大于今天的时间
    CheckIn time.Time `form:"check_in" binding:"required,bookabledate" time_format:"2006-01-02"`
    //gtfield=CheckIn退出的时间大于预约的时间
    CheckOut time.Time `form:"check_out" binding:"required,gtfield=CheckIn" time_format:"2006-01-02"`
}

func bookableDate(
    v *validator.Validate, topStruct reflect.Value, currentStructOrField reflect.Value,
    field reflect.Value, fieldType reflect.Type, fieldKind reflect.Kind, param string,
) bool {
    //field.Interface().(time.Time)获取参数值并且转换为时间格式
    if date, ok := field.Interface().(time.Time); ok {
        today := time.Now()
        if today.Unix() > date.Unix() {
            return false
        }
    }
    return true
}

func main() {
    route := gin.Default()
    //注册验证
    if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
        //绑定第一个参数是验证的函数第二个参数是自定义的验证函数
        v.RegisterValidation("bookabledate", bookableDate)
    }

    route.GET("/5lmh", getBookable)
    route.Run()
}

func getBookable(c *gin.Context) {
    var b Booking
    if err := c.ShouldBindWith(&b, binding.Query); err == nil {
        c.JSON(http.StatusOK, gin.H{"message": "Booking dates are valid!"})
    } else {
        c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
    }
}

// curl -X GET "http://localhost:8080/5lmh?check_in=2019-11-07&check_out=2019-11-20"
// curl -X GET "http://localhost:8080/5lmh?check_in=2019-09-07&check_out=2019-11-20"
// curl -X GET "http://localhost:8080/5lmh?check_in=2019-11-07&check_out=2019-11-01"