I am planning to implement Auto Validation

[Linde7777]

Related issue(but stale): #3167

I am planning to implement such feature.

Is your feature request related to a problem? Please describe.
Current auto validation rules is not enough.

Describe the solution you'd like
Imitating Gin's validator implementation.
There is a tag "binding", once you add that tag to the struct, when you call Bind()-like function(in go-zero, it is httpx.Parse()), it will automatically validate the struct's fields.
Gin underlying using the go-playground's validator, it has many validation rules, and also support custom validation rule.

Describe alternatives you've considered
Currently I have no alternatives for auto validation

Additional context
In Gin's implementation, the validation's interface has such function: Validate(obj any) error, and in go-zero, the validation interface's function is Validate() error, I not sure which I should use

[chenquan]

reference:

func init() {
	uni := ut.New(zh.New())
	trans, _ := uni.GetTranslator("zh")

	v := validator.New()
	logx.Must(zh_translations.RegisterDefaultTranslations(v, trans))

	httpx.SetValidator(&validate{validate: v})
}

type validate struct {
	validate *validator.Validate
}

func (v *validate) Validate(r *http.Request, data any) error {
	return v.validate.StructCtx(r.Context(), data)
}

[Linde7777]

Is the code you provided a suggestion for implementation?

I noticed that there are two interface:

// [email protected]/rest/httpx/requests.go 

// Validator defines the interface for validating the request.
type Validator interface {
	// Validate validates the request and parsed data.
	Validate(r *http.Request, data any) error
}

// [email protected]/core/validation/validator.go

// Validator represents a validator.
type Validator interface {
	// Validate validates the value.
	Validate() error
}

I’m curious about why there are two different interfaces. Could you please explain?

[chenquan]

Yes, just choose one of the two.

go-zero/rest/httpx/requests.go

Lines 55 to 59 in 01bbc78

	if valid, ok := v.(validation.Validator); ok {
	return valid.Validate()
	} else if val := validator.Load(); val != nil {
	return val.(Validator).Validate(r, v)
	}

[Linde7777]

go-zero/rest/httpx/requests.go

Lines 55 to 59 in 01bbc78

	if valid, ok := v.(validation.Validator); ok {
	return valid.Validate()
	} else if val := validator.Load(); val != nil {
	return val.(Validator).Validate(r, v)
	}

go-zero/rest/httpx/requests.go

Lines 31 to 35 in 01bbc78

	// Validator defines the interface for validating the request.
	type Validator interface {
	// Validate validates the request and parsed data.
	Validate(r *http.Request, data any) error
	}

question 1
I am confused about the design of the interface Validator, I think the validating functionality is not related to the http.Request, it only related to the struct

question 2
I am thinking about the lazy initlization of validator, so maybe we shouldn't write validator.Load(), we just need to call validator.Validate(), in the Validate(), it will call lazyinit(), which will be implemented by sync.Once

[chenquan]

1. It may be necessary to verify the path or header content.
2. Show your code and discuss it further.

[Linde7777]

It may be necessary to verify the path or header content.

For a struct, you can use a tag to register validation rules:

type SignUpReq struct{
	Email string `json:"email" binding:"required,email"`
	Password string `json:"password" binding:"required,complexpassword"`
}

But what would be the way to register a validation rule for path or header?

[Linde7777]

Show your code and discuss it further.

https://github.com/Linde7777/go-zero/tree/auto_validation/rest/httpx

I have finished the part of validating struct and the lazy initialization

[chenquan]

It may be necessary to verify the path or header content.

For a struct, you can use a tag to register validation rules:

type SignUpReq struct{
	Email string `json:"email" binding:"required,email"`
	Password string `json:"password" binding:"required,complexpassword"`
}

But what would be the way to register a validation rule for path or header?

for example:

go-zero/rest/httpx/requests_test.go

Lines 509 to 514 in 4a62d08

	if r.URL.Path == "/a" {
	val := reflect.ValueOf(data).Elem().FieldByName("Name").String()
	if val != "hello" {
	return errors.New("name is not hello")
	}
	}

[chenquan]

Show your code and discuss it further.

https://github.com/Linde7777/go-zero/tree/auto_validation/rest/httpx

I have finished the part of validating struct and the lazy initialization

Yes, you can.

[Linde7777]

go-zero/rest/httpx/requests_test.go

Lines 509 to 514 in 4a62d08

	if r.URL.Path == "/a" {
	val := reflect.ValueOf(data).Elem().FieldByName("Name").String()
	if val != "hello" {
	return errors.New("name is not hello")
	}
	}

It seems that the code you provide didn't answer "how to register validation rules for http.Request?"

For register validation rule of http.Request, I have figured out two method:

method 1: define the validation rule for http.Request in the struct

type SignUpReq struct{
	Email string `json:"email" binding:"required,email" rv:"xxrequestvalidationrule"`
	Password string `json:"password" binding:"required,complexpassword"`
}

The tag "rv" is for "Request Validation".
The user need to define the rule in the first field of struct.

method 2: using a middleware

We don't need to validate request in the interface Validator

[chenquan]

go-zero provides validation.Validator interface and validator Validator to help users customize validation capabilities, you can choose according to the business background and personal preferences of the appropriate way to extend the validation capabilities. There is no need to modify the go-zero source code.

validation.Validator :

go-zero/core/validation/validator.go

Lines 3 to 7 in 4a62d08

	// Validator represents a validator.
	type Validator interface {
	// Validate validates the value.
	Validate() error
	}

validator:

go-zero/rest/httpx/requests.go

Line 28 in 4a62d08

validator atomic.Value

go-zero/rest/httpx/requests.go

Lines 126 to 128 in 4a62d08

	func SetValidator(val Validator) {
	validator.Store(val)
	}

I hope this answer answers your initial question.

[Linde7777]

I got it, what about setting go-playground's validator as a default validator? I think many people would like to use it. The implementation will be lazy initialization.

[chenquan]

Hello, I don't think it's necessary, because go-zero already provides the ability to extend validation. But you can launch a PR to allow more people to see your code to further discuss the need for a merger.

[Linde7777]

ok, thank you!

[kevwan]

https://medium.com/dev-genius/the-elegance-of-go-interface-b4c9c00012da

I've written an post to introduce how to use go-playground/validator in go-zero.