Golang implements registration and login

In the Internet era, with the continuous advancement of Internet technology and people's increasing demand for information, the registration and login functions of websites and APPs have become more and more common. This article will introduce how to use golang language to implement the registration and login function.

1. Introduction to golang

Golang is a programming language developed by Google. It has the characteristics of efficient concurrent processing, automatic garbage collection, and extremely low compilation time. It has natural Concurrency capabilities and features suitable for large-scale systems. These features make golang a very excellent server-side language. Therefore, using it to implement the registration and login function is a very good choice.

2. Environment setup

To use golang to implement the registration and login function, you first need to install the golang language in the local environment. Before installation, you need to determine the operating system type of your computer (Windows, Linux, Mac, etc.), and select the corresponding golang version to download and install.

After the installation is completed, you can enter the following command on the command line to check whether the installation is successful:

go version

If the version number of golang is displayed, the installation is successful.

3. Registration function implementation

1. Create project folder

Create a folder named "login" to place this project document. Create two folders in this folder: controller and model. Among them, controller is used to place the controller code of the Web interface, and model is used to place the code of database operations.

2. Database connection and table creation

Create a file named "db.go" in the model folder, and write the following code in it to establish a database connection :

package model

import (
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql"
)

const (
    USERNAME = "root"
    PASSWORD = ""
    NETWORK  = "tcp"
    SERVER   = "localhost"
    PORT     = 3306
    DATABASE = "login_system"
)

func DbConn() (db *sql.DB) {
    dbDriver := "mysql"
    dbUser := USERNAME
    dbPass := PASSWORD
    dbName := DATABASE
    db, err := sql.Open(dbDriver, dbUser+":"+dbPass+"@tcp("+SERVER+":"+strconv.Itoa(PORT)+")/"+dbName)
    if err != nil {
        fmt.Println("无法连接数据库：", err)
    } else {
        fmt.Println("成功连接数据库！")
    }
    return db
}

In the above code, the third-party library "go-sql-driver/mysql" is used to realize the database connection. In the code, we also need to set some basic information of the database, such as user name, password, host address, port number, database name, etc.

Next step, we need to create a file named "user.sql" to write the SQL statement to create the user table, which contains fields such as user ID, user name and password.

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(20) NOT NULL,
  `password` varchar(40) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

By executing the above SQL statement, the user table can be created in the database.

3. Write controller code

Create a file named "register.go" in the controller folder to write the controller code for the registration interface. In this file, you need to import the third-party library "net/http" and write the following code:

package controller

import (
    "crypto/md5"
    "database/sql"
    "encoding/hex"
    "fmt"
    "io/ioutil"
    "net/http"
    "server/model"
)

func Register(w http.ResponseWriter, r *http.Request) {
    if r.Method == "POST" {
        username := r.FormValue("username")
        password := r.FormValue("password")
        // 密码加密
        h := md5.New()
        h.Write([]byte(password))
        password = hex.EncodeToString(h.Sum(nil))
        // 数据库操作
        db := model.DbConn()
        defer db.Close()
        stmt, err := db.Prepare("INSERT INTO user(username, password) VALUES (?, ?)")
        if err != nil {
            fmt.Println("SQL语句执行失败：", err)
            return
        }
        _, err = stmt.Exec(username, password)
        if err != nil {
            fmt.Println("用户注册失败：", err)
            return
        }
        fmt.Println("用户注册成功！")
    }
    // 返回页面内容
    data, err := ioutil.ReadFile("register.html")
    if err != nil {
        fmt.Println("读取文件失败：", err)
        return
    }
    w.Write([]byte(data))
}

In the above code, we first determine whether the request method is POST. If it is a POST request, the user name and password are obtained, the password is MD5 encrypted, and the encrypted password and user name are stored in the database.

At the end of the file, use the ioutil.ReadFile() function to read a file named "register.html" and return the content of the file to the browser. In this way, the browser can display our registration interface.

4. Registration interface writing

Create a file named "register.html" in the login folder to write the code for the registration page. In this page, you need to use the

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>注册</title>
</head>
<body>
    <form action="/register" method="post">
        <p>用户名：<input type="text" name="username" /></p>
        <p>密码：<input type="password" name="password" /></p>
        <input type="submit" value="注册" />
    </form>
</body>
</html>

package main

import (
    "net/http"
    "login/controller"
)

func main() {
    // 注册接口路由
    http.HandleFunc("/register", controller.Register)
    // 启动服务器
    http.ListenAndServe(":8080", nil)
}

package controller

import (
    "crypto/md5"
    "database/sql"
    "encoding/hex"
    "fmt"
    "io/ioutil"
    "net/http"
    "server/model"    
)

func Login(w http.ResponseWriter, r *http.Request) {
    if r.Method == "POST" {
        username := r.FormValue("username")
        password := r.FormValue("password")
        h := md5.New()
        h.Write([]byte(password))
        password = hex.EncodeToString(h.Sum(nil))
        // 根据用户名和密码查询数据库
        db := model.DbConn()
        defer db.Close()
        rows, err := db.Query("SELECT * FROM user WHERE username=? AND password=?", username, password)
        if err != nil {
            fmt.Println("SQL语句执行失败：", err)
            return
        }
        defer rows.Close()
        if rows.Next() {
            fmt.Println("登录成功！")
            // 返回登录成功页面
            data, err := ioutil.ReadFile("success.html")
            if err != nil {
                fmt.Println("读取文件失败：", err)
                return
            }
            w.Write([]byte(data))
        } else {
            fmt.Println("用户名或密码不正确！")
            // 返回登录失败页面
            data, err := ioutil.ReadFile("fail.html")
            if err != nil {
                fmt.Println("读取文件失败：", err)
                return
            }
            w.Write([]byte(data))
        }
    }
    // 返回登录页面
    data, err := ioutil.ReadFile("login.html")
    if err != nil {
        fmt.Println("读取文件失败：", err)
        return
    }
    w.Write([]byte(data))
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录</title>
</head>
<body>
    <form action="/login" method="post">
        <p>用户名：<input type="text" name="username" /></p>
        <p>密码：<input type="password" name="password" /></p>
        <input type="submit" value="登录" />
    </form>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录成功</title>
</head>
<body>
    <h1>恭喜，登录成功！</h1>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录失败</title>
</head>
<body>
    <h1>对不起，用户名或密码错误！</h1>
</body>
</html>

package main

import (
    "net/http"
    "login/controller"
)

func main() {
    // 注册接口路由
    http.HandleFunc("/", controller.Register)
    // 登录接口路由
    http.HandleFunc("/login", controller.Login)
    // 启动服务器
    http.ListenAndServe(":8080", nil)
}