Golang learning form validation practice for web applications

In web development, form validation is an extremely critical part. Form verification can effectively protect data security and prevent attacks and malicious operations by illegal users. In Golang, form validation technology is also widely used, especially in web applications. This article will introduce the practice of form validation for web applications in Golang.

1. Basic principles of form validation

In web applications, the basic principle of form validation is to check and verify data before submitting data on the web page. This data may be username, password, email, phone number, etc. entered by the user, or other fields that need to be verified and processed. Before validating this data, you need to define the data type and validation rules. Regular expressions are usually used for data validation. If the data verification passes, the data can be submitted to the web server for processing. Otherwise, the user needs to be prompted to enter correct data and refill the form.

2. How to implement form validation in Golang

In Golang, there are many ways to implement form validation. The following is a basic implementation method:

1. Define the structure

First, we need to define a structure to store the data submitted in the form. Fields in the structure need to define corresponding types and validation rules.

type User struct {
    Name     string `form:"name" binding:"required"`
    Password string `form:"password" binding:"required,min=6,max=20"`
    Email    string `form:"email" binding:"required,email"`
    Phone    string `form:"phone" binding:"required,phone"`
}

In the above code, we define a User structure, which has four fields representing user name, password, email and phone number. In the structure field, we use Golang's tag technology. For example, form:"name" means that the name attribute of this field in the web form is name, binding:"required" means that this field is required.

2. Define route

Next, we need to define the route and bind the corresponding processing function. Use the POST method in the route to receive the data submitted by the form.

router.POST("/register", func(c *gin.Context) {
    var user User
    if err := c.ShouldBind(&user); err != nil {
        c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
        return
    }

    // 数据验证通过，提交到Web服务器处理
    c.JSON(http.StatusOK, gin.H{"success": "注册成功"})
})

In the above code, we use c.ShouldBind(&user) to bind the data submitted in the web form to the User structure. If the binding fails, the corresponding error message will be returned. If the binding is successful, it means that the data verification has passed and the data can be submitted to the web server for processing.

3. Form validation

Before performing form validation, we need to import the github.com/go-playground/validator/v10 package in Golang . This package is the primary tool for validating form data.

import (
    "net/http"

    "github.com/gin-gonic/gin"
    "github.com/go-playground/validator/v10"
)

// 自定义验证函数
var validate *validator.Validate

func init() {
    validate = validator.New()
    validate.RegisterValidation("phone", validatePhone)
}

func validatePhone(fl validator.FieldLevel) bool {
    phone := fl.Field().String()
    if phone == "" {
        return true
    }
    if !regexp.MustCompile(`^1[3456789]d{9}$`).MatchString(phone) {
        return false
    }
    return true
}

In the above code, we first define a global validate object, and then define a custom verification function named validatePhone. This function checks whether the phone number complies with the rules.

Finally, in the routing processing function, we can use validate.Struct(user) to verify the data in the User structure. For example:

if err := validate.Struct(user); err != nil {
    c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
    return
}

If the verification fails, the corresponding error message will be returned. If the verification is successful, the data can be submitted to the web server for processing.

3. Summary

This article introduces the form validation practice of web applications in Golang. In Golang, form validation of data can be easily implemented using technologies such as structures, routing, and validation libraries. In actual development, we need to define structures, validation rules and routing according to the actual needs of users. I hope this article can provide some reference for beginners.

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