快速搭建一个go语言web后端服务脚手架

源码：https://github.com/weloe/go-web-demo

web框架使用gin，数据操作使用gorm，访问控制使用casbin

首先添加一下自定义的middleware

recover_control.go ，统一处理panic error返回的信息

package middleware

import (
    "fmt"
    "github.com/gin-gonic/gin"
    "go-web-demo/component"
    "log"
    "net/http"
)

func Recover(c *gin.Context) {
    defer func() {
        if r := recover(); r != nil {
            // print err msg
            log.Printf("panic: %v\n", r)
            // debug.PrintStack()
            // response same struct
            c.JSON(http.StatusBadRequest, component.RestResponse{Code: -1, Message: fmt.Sprintf("%v", r)})
        }
    }()

    c.Next()
}

access_control.go 使用casbin进行访问控制的中间件

package middleware

import (
    "fmt"
    "github.com/casbin/casbin/v2"
    gormadapter "github.com/casbin/gorm-adapter/v3"
    "github.com/gin-gonic/gin"
    _ "github.com/go-sql-driver/mysql"
    "go-web-demo/component"
    "log"
    "net/http"
)

// DefaultAuthorize determines if current subject has been authorized to take an action on an object.
func DefaultAuthorize(obj string, act string) gin.HandlerFunc {
    return func(c *gin.Context) {

        // Get current user/subject
        token := c.Request.Header.Get("token")
        if token == "" {
            c.AbortWithStatusJSON(http.StatusUnauthorized, component.RestResponse{Message: "token is nil"})
            return
        }
        username, err := component.GlobalCache.Get(token)
        if err != nil || string(username) == "" {
            log.Println(err)
            c.AbortWithStatusJSON(http.StatusUnauthorized, component.RestResponse{Message: "user hasn't logged in yet"})
            return
        }

        // Casbin enforces policy
        ok, err := enforce(string(username), obj, act, component.Enforcer)
        if err != nil {
            log.Println(err)
            c.AbortWithStatusJSON(http.StatusInternalServerError, component.RestResponse{Message: "error occurred when authorizing user"})
            return
        }
        if !ok {
            c.AbortWithStatusJSON(http.StatusForbidden, component.RestResponse{Message: "forbidden"})
            return
        }

        c.Next()
    }
}

func enforce(sub string, obj string, act string, enforcer *casbin.Enforcer) (bool, error) {
    // Load policies from DB dynamically
    err := enforcer.LoadPolicy()
    if err != nil {
        return false, fmt.Errorf("failed to load policy from DB: %w", err)
    }
    // Verify
    ok, err := enforcer.Enforce(sub, obj, act)
    return ok, err
}

func AuthorizeAdapterAndModel(obj string, act string, adapter *gormadapter.Adapter, model string) gin.HandlerFunc {
    return func(c *gin.Context) {

        // Get current user/subject
        token := c.Request.Header.Get("token")
        if token == "" {
            c.AbortWithStatusJSON(401, component.RestResponse{Message: "token is nil"})
            return
        }
        username, err := component.GlobalCache.Get(token)
        if err != nil || string(username) == "" {
            log.Println(err)
            c.AbortWithStatusJSON(401, component.RestResponse{Message: "user hasn't logged in yet"})
            return
        }

        // Load model configuration file and policy store adapter
        enforcer, err := casbin.NewEnforcer(model, adapter)
        // Casbin enforces policy
        ok, err := enforce(string(username), obj, act, enforcer)

        if err != nil {
            log.Println(err)
            c.AbortWithStatusJSON(500, component.RestResponse{Message: "error occurred when authorizing user"})
            return
        }
        if !ok {
            c.AbortWithStatusJSON(403, component.RestResponse{Message: "forbidden"})
            return
        }

        c.Next()
    }
}

reader.go 读取yaml配置文件的根据类，使用了viter

package config

import (
    "fmt"
    "github.com/spf13/viper"
    "log"
    "sync"
    "time"
)

type Config struct {
    Server     *Server
    Mysql      *DB
    LocalCache *LocalCache
    Casbin     *Casbin
}

type Server struct {
    Port int64
}

type DB struct {
    Username string
    Password string
    Host     string
    Port     int64
    Dbname   string
    TimeOut  string
}

type LocalCache struct {
    ExpireTime time.Duration
}

type Casbin struct {
    Model string
}

var (
    once   sync.Once
    Reader = new(Config)
)

func (config *Config) ReadConfig() *Config {
    once.Do(func() {
        viper.SetConfigName("config")   // filename
        viper.SetConfigType("yaml")     // filename extension : yaml | json |
        viper.AddConfigPath("./config") // workspace dir : ./
        var err error
        err = viper.ReadInConfig() // read config
        if err != nil {            // handler err
            log.Fatalf(fmt.Sprintf("Fatal error config file: %s \n", err))
        }
        err = viper.Unmarshal(config)
        if err != nil {
            log.Fatalf(fmt.Sprintf("Fatal error viper unmarshal config: %s \n", err))
        }
    })
    return Reader
}

配置文件

server:
  port: 8080

mysql:
  username: root
  password: pwd
  host: 127.0.0.1
  port: 3306
  dbname: casbin_demo
  timeout: 10s

localCache:
  expireTime: 60

casbin:
  model: config/rbac_model.conf

persistence.go， gorm，bigcache, casbin 初始化，这里用的casbin是从数据库读取policy

package component

import (
    "fmt"
    "github.com/allegro/bigcache"
    "github.com/casbin/casbin/v2"
    gormadapter "github.com/casbin/gorm-adapter/v3"
    _ "github.com/go-sql-driver/mysql"
    "go-web-demo/config"
    "gorm.io/driver/mysql"
    "gorm.io/gorm"
    "log"
    "time"
)

var (
    DB          *gorm.DB
    GlobalCache *bigcache.BigCache
    Enforcer    *casbin.Enforcer
)

// CreateByConfig create components
func CreateByConfig() {

    ConnectDB()

    CreateLocalCache()

    CreateCasbinEnforcer()
}

func ConnectDB() {
    // connect to DB
    var err error
    dbConfig := config.Reader.ReadConfig().Mysql
    if dbConfig == nil {
        log.Fatalf(fmt.Sprintf("db config is nil"))
    }
    // config
    username := dbConfig.Username
    password := dbConfig.Password
    host := dbConfig.Host
    port := dbConfig.Port
    Dbname := dbConfig.Dbname
    timeout := dbConfig.TimeOut

    dbUrl := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8&parseTime=True&loc=Local&timeout=%s", username, password, host, port, Dbname, timeout)
    log.Println("connect db url: " + dbUrl)
    DB, err = gorm.Open(mysql.Open(dbUrl), &gorm.Config{})

    if err != nil {
        log.Fatalf(fmt.Sprintf("failed to connect to DB: %v", err))
    }
}

func CreateLocalCache() {
    var err error
    cacheConfig := config.Reader.ReadConfig().LocalCache
    if cacheConfig == nil {
        log.Fatalf(fmt.Sprintf("cache config is nil"))
    }
    // Initialize cache to store current user in cache.
    GlobalCache, err = bigcache.NewBigCache(bigcache.DefaultConfig(cacheConfig.ExpireTime * time.Second)) // Set expire time to 30 s
    if err != nil {
        log.Fatalf(fmt.Sprintf("failed to initialize cahce: %v", err))
    }
}

func CreateCasbinEnforcer() {
    var err error

    // casbin model
    config := config.Reader.ReadConfig().Casbin
    if config == nil {
        log.Fatalf(fmt.Sprintf("casbin config is nil"))
    }
    model := config.Model
    //Initialize casbin adapter
    adapter, _ := gormadapter.NewAdapterByDB(DB)

    // Load model configuration file and policy store adapter
    Enforcer, err = casbin.NewEnforcer(model, adapter)
    if err != nil {
        log.Fatalf(fmt.Sprintf("failed to create casbin enforcer: %v", err))
    }

}

到这里准备工作基本完成，我们来写一个通用的 登录，注册，退出 业务吧

user_handler.go

package handler

import (
    "fmt"
    "github.com/gin-gonic/gin"
    "github.com/gin-gonic/gin/binding"
    "go-web-demo/component"
    "go-web-demo/handler/request"
    "go-web-demo/service"
    "net/http"
)

func Login(c *gin.Context) {
    loginRequest := &request.Login{}
    err := c.ShouldBindBodyWith(loginRequest, binding.JSON)
    if err != nil {
        panic(fmt.Errorf("request body bind error: %v", err))
    }
    token := service.Login(loginRequest)

    c.JSON(http.StatusOK, component.RestResponse{Code: 1, Data: token, Message: loginRequest.Username + " logged in successfully"})

}

func Logout(c *gin.Context) {
    token := c.Request.Header.Get("token")

    if token == "" {
        panic(fmt.Errorf("token error: token is nil"))
    }

    bytes, err := component.GlobalCache.Get(token)

    if err != nil {
        panic(fmt.Errorf("token error: failed to get username: %v", err))
    }

    username := string(bytes)
    // Authentication

    // Delete store current subject in cache
    err = component.GlobalCache.Delete(token)
    if err != nil {
        panic(fmt.Errorf("failed to delete current subject in cache: %w", err))
    }

    c.JSON(http.StatusOK, component.RestResponse{Code: 1, Data: token, Message: username + " logout in successfully"})
}

func Register(c *gin.Context) {
    register := &request.Register{}
    err := c.ShouldBindBodyWith(register, binding.JSON)
    if err != nil {
        c.JSON(400, component.RestResponse{Code: -1, Message: " bind error"})
        return
    }

    service.Register(register)

    c.JSON(http.StatusOK, component.RestResponse{Code: 1, Data: nil, Message: "register successfully"})
}

service.user.go

这里要注意 注册的时候我们做了两个操作，注册到user表，把policy写入到casbin_rule表，要保证他们要同时成功，所以要用事务

func Login(loginRequest *request.Login) string {
    password := loginRequest.Password
    username := loginRequest.Username

    // Authentication
    user := dao.GetByUsername(username)
    if password != user.Password {
        panic(fmt.Errorf(username + " logged error : password error"))
    }

    // Generate random uuid token
    u, err := uuid.NewRandom()
    if err != nil {
        panic(fmt.Errorf("failed to generate UUID: %w", err))
    }
    // Sprintf token
    token := fmt.Sprintf("%s-%s", u.String(), "token")
    // Store current subject in cache
    err = component.GlobalCache.Set(token, []byte(username))
    if err != nil {
        panic(fmt.Errorf("failed to store current subject in cache: %w", err))
    }
    // Send cache key back to client cookie
    //c.SetCookie("current_subject", token, 30*60, "/resource", "", false, true)
    return token
}

func Register(register *request.Register) {
    var err error
    e := component.Enforcer
    err = e.GetAdapter().(*gormadapter.Adapter).Transaction(e, func(copyEnforcer casbin.IEnforcer) error {
        // Insert to table
        db := copyEnforcer.GetAdapter().(*gormadapter.Adapter).GetDb()
        res := db.Exec("insert into user (username,password) values(?,?)", register.Username, register.Password)

        //User has Username and Password
        //res := db.Table("user").Create(&User{
        //  Username: register.Username,
        //  Password: register.Password,
        //})

        if err != nil || res.RowsAffected < 1 {
            return fmt.Errorf("insert error: %w", err)
        }

        _, err = copyEnforcer.AddRoleForUser(register.Username, "role::user")
        if err != nil {
            return fmt.Errorf("add plocy error: %w", err)
        }
        return nil
    })

    if err != nil {
        panic(err)
    }

}

dao.user.go 对数据库的操作

package dao

import "go-web-demo/component"

type User struct {
    Id       int64 `gorm:"primaryKey"`
    Username string
    Password string
    Email    string
    Phone    string
}

func (u *User) TableName() string {
    return "user"
}

func GetByUsername(username string) *User {
    res := new(User)
    component.DB.Model(&User{}).Where("username = ?", username).First(res)
    return res
}

func Insert(username string, password string) (int64, error, int64) {
    user := &User{Username: username, Password: password}
    res := component.DB.Create(&user)

    return user.Id, res.Error, res.RowsAffected
}

最后一步，启动web服务，配置路由

package main

import (
    "fmt"
    "github.com/gin-contrib/cors"
    "github.com/gin-gonic/gin"
    "go-web-demo/component"
    "go-web-demo/config"
    "go-web-demo/handler"
    "go-web-demo/middleware"
    "log"
)

var (
    router *gin.Engine
)

func init() {
    //Initialize components from config yaml: mysql locaCache casbin
    component.CreateByConfig()

    // Initialize gin engine
    router = gin.Default()

    // Initialize gin middleware
    corsConfig := cors.DefaultConfig()
    corsConfig.AllowAllOrigins = true
    corsConfig.AllowCredentials = true
    router.Use(cors.New(corsConfig))
    router.Use(middleware.Recover)

    // Initialize gin router
    user := router.Group("/user")
    {
        user.POST("/login", handler.Login)
        user.POST("/logout", handler.Logout)
        user.POST("/register", handler.Register)
    }

    resource := router.Group("/api")
    {
        resource.Use(middleware.DefaultAuthorize("user::resource", "read-write"))
        resource.GET("/resource", handler.ReadResource)
        resource.POST("/resource", handler.WriteResource)
    }

}

func main() {
    // Start
    port := config.Reader.Server.Port
    err := router.Run(":" + port)
    if err != nil {
        panic(fmt.Sprintf("failed to start gin engine: %v", err))
    }
    log.Println("application is now running...")
}

表结构和相关测试数据

CREATE DATABASE /*!32312 IF NOT EXISTS*/`casbin_demo` /*!40100 DEFAULT CHARACTER SET utf8 */;

USE `casbin_demo`;

/*Table structure for table `casbin_rule` */

DROP TABLE IF EXISTS `casbin_rule`;

CREATE TABLE `casbin_rule` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `ptype` varchar(100) NOT NULL,
  `v0` varchar(100) DEFAULT NULL,
  `v1` varchar(100) DEFAULT NULL,
  `v2` varchar(100) DEFAULT NULL,
  `v3` varchar(100) DEFAULT NULL,
  `v4` varchar(100) DEFAULT NULL,
  `v5` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `idx_casbin_rule` (`v0`,`v1`,`v2`,`v3`,`v4`,`v5`)
) ENGINE=InnoDB AUTO_INCREMENT=64 DEFAULT CHARSET=utf8;

/*Data for the table `casbin_rule` */

insert  into `casbin_rule`(`id`,`ptype`,`v0`,`v1`,`v2`,`v3`,`v4`,`v5`) values 

(3,'p','role::admin','admin::resource','read-write','','',''),

(5,'p','role::user','user::resource','read-write','','',''),

(57,'g','test1','role::user','','','',''),

(59,'g','role::admin','role::user','','','',''),

(63,'g','test2','role::admin',NULL,NULL,NULL,NULL);

/*Table structure for table `user` */

DROP TABLE IF EXISTS `user`;

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(50) DEFAULT NULL,
  `password` varchar(50) DEFAULT NULL,
  `email` varchar(50) DEFAULT NULL,
  `phone` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=39 DEFAULT CHARSET=utf8;

/*Data for the table `user` */

insert  into `user`(`id`,`username`,`password`,`email`,`phone`) values 

(36,'test1','123',NULL,NULL),

(38,'test2','123',NULL,NULL);