英文:
How to access to interface of a pointered function
问题
对于验证器，我有以下接口：
type validatorInterface interface {
IsValid() error
}
func customValidation(fl validator.FieldLevel) bool {
field := fl.Field().Interface()
validatorObject, ok := field.(validatorInterface)
if !ok {
return false
}
err := validatorObject.IsValid()
if err != nil {
return false
}
return true
}
如果要验证的字段实现的函数没有指针，它可以完美地工作，就像这样：
func (s s) IsValid()
但是，如果实现的函数是这样的：
func (s *s) IsValid()
将其转换为接口时会失败。我该如何改进customValidation来解决这个问题？
英文:
For the validator I have the following interface
type validatorInterface interface {
IsValid() error
}
func customValidation(fl validator.FieldLevel) bool {
field := fl.Field().Interface()
validatorObject, ok := field.(validatorInterface)
if !ok {
return false
}
err := validatorObject.IsValid()
if err != nil {
return false
}
return true
}
It work perfect if the field to validate has the function implemented without pointer. Like that:
func (s s) IsValid()
but the conversion to the interface fails if it is implemented like that
func (s *s) IsValid()
How can I improve the customValidation to solve the problem
答案1
得分: 1
好的，以下是翻译好的内容：
好的，最终我找到了答案。我记得 encoding/json 库可以做到这一点，所以我查看了它，找到了以下代码：
// 如果 v 是一个命名类型并且是可寻址的，
// 首先使用它的地址，这样如果该类型有指针方法，
// 我们就可以找到它们。
if v.Kind() != reflect.Pointer && v.Type().Name() != "" && v.CanAddr() {
haveAddr = true
v = v.Addr()
}
我按照这种方式实现了它，并且它可以正常工作。
英文:
OK, finally I found and answer. I remember that the encoding/json library do that so I looked at it and I found
// If v is a named type and is addressable,
// start with its address, so that if the type has pointer methods,
// we find them.
if v.Kind() != reflect.Pointer && v.Type().Name() != "" && v.CanAddr() {
haveAddr = true
v = v.Addr()
}
I implemented that in that way and it works correctly.
答案2
得分: 0
如果是通过引用实现的，你需要fl.Field().Interface()返回一个引用。
https://go.dev/play/p/iYTibDNrH5E
嗯，这样也更准确，因为如果方法是通过引用传递的，你可能想要传递一个对象的引用。
英文:
If it is implemented by reference, you need that fl.Field().Interface() will return an reference.
https://go.dev/play/p/iYTibDNrH5E
Well, it's also more accurate, since if the method is by reference, you probably want to pass a reference to the object.
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