从零开始实现简单的webapi框架【Golang 入门系列】

之前，已经讲过很多Golang的东西，比如基础语法，mysql的使用，redis的使用等等，感兴趣的可以看看以前的文章，https://www.cnblogs.com/zhangweizhong/category/1275863.html，

今天就用从头写一个完整的go的示例项目吧。

本项目完全使用原生开发，没有使用任何WEB框架和ORM。虽然大家对mvc 呀，三层架构已经很了解了。但是，我还是想从头写一个完整的示例项目。这样大家有一个更深刻的了解，这样以后介绍web框架，orm框架的时候，学习起来应该会简单一点。

项目架构

下图这种架构模式相信大家应该十分清楚

Controller组合封装

Controller"基类"封装

packageframeworktypeControllerstruct{Datainterface{}}

UserController定义了用户注册，登录和查询等简单的三个接口

packagecontrollerimport("net/http""micro-cloud/service""micro-cloud/utils""micro-cloud/framework")/** * r.PostFormValue  : 可以解析 Post/PUT Content-Type=application/x-www-form-urlencoded 或 Content-Type=multipart/form-data */typeUserConterllerstruct{}varuserService =new(service.UserService)func(p *UserConterller)Router(router *framework.RouterHandler){router.Router("/register", p.register)router.Router("/login", p.login)router.Router("/findAll", p.findAll)}//POST Content-Type=application/x-www-form-urlencodedfunc(p *UserConterller)register(w http.ResponseWriter, r *http.Request){username := r.PostFormValue("username")password := r.PostFormValue("password")ifutils.Empty(username) || utils.Empty(password) {microcloud.ResultFail(w,"username or password can not be empty")return  }  id := userService.Insert(username, password)ifid <=0{microcloud.ResultFail(w,"register fail")return  }microcloud.ResultOk(w,"register success")}//POST Content-Type=application/x-www-form-urlencodedfunc(p *UserConterller)login(w http.ResponseWriter, r *http.Request){username := r.PostFormValue("username")password := r.PostFormValue("password")ifutils.Empty(username) || utils.Empty(password) {microcloud.ResultFail(w,"username or password can not be empty")return  }  users := userService.SelectUserByName(username)iflen(users) ==0{microcloud.ResultFail(w,"user does not exist")return  }ifusers[0].Password != password {microcloud.ResultFail(w,"password error")return  }microcloud.ResultOk(w,"login success")}// GET/POSTfunc(p *UserConterller)findAll(w http.ResponseWriter, r *http.Request){  users := userService.SelectAllUser()  framework.ResultJsonOk(w, users)}

数据访问层

packagedaoimport("micro-cloud/model""fmt"    )typeUserDaostruct{}func(p *UserDao)Insert(user *model.User)int64{result, err := framework.DB.Exec("INSERT INTO user(`username`,`password`,`create_time`) value(?,?,?)", user.Username, user.Password, user.CreateTime)iferr !=nil{fmt.Println("Insert error")return0    }    id, err := result.LastInsertId()iferr !=nil{fmt.Println("Insert error")return0    }returnid}func(p *UserDao)SelectUserByName(usernamestring)[]model.User{rows, err := framework.DB.Query("SELECT * FROM user WHERE username = ?", username)iferr !=nil{fmt.Println("selectuserbyname error")returnnil    }varusers []model.Userforrows.Next() {varuser model.User        err := rows.Scan(&user.ID, &user.Username, &user.Password, &user.CreateTime)iferr !=nil{fmt.Println("selectuserbyname error")continue        }users =append(users, user)    }    rows.Close()returnusers}func(p *UserDao)SelectAllUser()[]model.User{rows, err := framework.DB.Query("SELECT * FROM user")iferr !=nil{fmt.Println("SelectAllUser error")returnnil    }varusers []model.Userforrows.Next() {varuser model.User        err := rows.Scan(&user.ID, &user.Username, &user.Password, &user.CreateTime)iferr !=nil{fmt.Println("SelectAllUser error")continue        }users =append(users, user)    }    rows.Close()returnusers}

实体层

packagemodelimport"time"typeUserstruct{IDuint`json:"id"`Usernamestring`json:"username"`Passwordstring`json:"-"`CreateTime time.Time`json:"create_time"`}

database

数据库操作类的实现

packagemicrocloudimport("database/sql""log""strings"_"github.com/go-sql-driver/mysql")//数据库的配置const(username  ="admin"password  ="123456"ip        ="10.2.1.5"port      ="3306"dbName    ="microcloud"driverName ="mysql")//DB数据库连接池varDB *sql.DBfuncInitDB(){//构建连接："用户名:密码@tcp(IP:端口)/数据库?charset=uft8"//注意：要想解析time.Time类型，必须要设置parseTime=Truepath := strings.Join([]string{username,":", password,"@tcp(", ip,":", port,")/", dbName,"?charset=utf8&parseTime=True&loc=Local"},"")//打开数据库，前者是驱动名，所以要导入:_"github.com/go-sql-driver/mysql"    DB, _ = sql.Open(driverName, path)//设置数据库最大连接数DB.SetConnMaxLifetime(100)//设置数据库最大闲置连接数DB.SetMaxIdleConns(10)//验证连接iferr := DB.Ping(); err !=nil{        log.Panic(err)    }log.Println("database connect success")}funcCreateTable(){userTable :="CREATE TABLE IF NOT EXISTS `user`("+"`id` INT UNSIGNED AUTO_INCREMENT,"+"`username` VARCHAR(20) NOT NULL,"+"`password` VARCHAR(40) NOT NULL,"+"`create_time` DATETIME,"+"PRIMARY KEY ( `id` )"+")ENGINE=InnoDB DEFAULT CHARSET=utf8;"    _, err := DB.Exec(userTable)iferr !=nil{        log.Panic(err)    }}

http

http server的实现

server:= &http.Server{Addr:":8215",Handler:microcloud.Router,ReadTimeout:5 * time.Second,}RegiterRouter(microcloud.Router)err:= server.ListenAndServe()iferr != nil {log.Panic(err)}

Router

路由处理的实现，其实也就是一个转发的功能

type RouterHandler struct {}varmux = make(map[string]func(http.ResponseWriter,*http.Request))func (p *RouterHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {    fmt.Println(r.URL.Path)iffun, ok := mux[r.URL.Path]; ok {fun(w, r)return    }//静态资源ifstrings.HasPrefix(r.URL.Path,constant.STATIC_BAES_PATH){iffun, ok := mux[constant.STATIC_BAES_PATH]; ok {fun(w, r)return        }    }http.Error(w,"error URL:"+r.URL.String(), http.StatusBadRequest)}func (p *RouterHandler) Router(relativePath string, handler func(http.ResponseWriter, *http.Request)) {    mux[relativePath] = handler}

演示

执行 go run main.go 之后，打开Postman，调相关的接口

以下就是访问API的请求与响应

 /findAll 接口

/register 接口

最后

以上，用Go语言实现webapi 的例子，已经介绍完了，虽然比较简单，session，权限验证等都没有加。