Golang 入门系列（十一）Go语言实现webapi

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

package framework

type Controller struct {
   Data interface{}
}

UserController定义了用户注册，登录和查询等简单的三个接口

package controller

import (
   "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
 */

type UserConterller struct {

}

var userService = 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-urlencoded
func (p *UserConterller) register(w http.ResponseWriter, r *http.Request) {
   username := r.PostFormValue("username")
   password := r.PostFormValue("password")
   if utils.Empty(username) || utils.Empty(password) {
      microcloud.ResultFail(w, "username or password can not be empty")
      return
   }
   id := userService.Insert(username, password)
   if id <= 0 {
      microcloud.ResultFail(w, "register fail")
      return
   }
   microcloud.ResultOk(w, "register success")
}

//POST Content-Type=application/x-www-form-urlencoded
func (p *UserConterller) login(w http.ResponseWriter, r *http.Request) {
   username := r.PostFormValue("username")
   password := r.PostFormValue("password")
   if utils.Empty(username) || utils.Empty(password) {
      microcloud.ResultFail(w, "username or password can not be empty")
      return
   }
   users := userService.SelectUserByName(username)
   if len(users) == 0 {
      microcloud.ResultFail(w, "user does not exist")
      return
   }
   if users[0].Password != password {
      microcloud.ResultFail(w, "password error")
      return
   }

   microcloud.ResultOk(w, "login success")
}

// GET/POST
func (p *UserConterller) findAll(w http.ResponseWriter, r *http.Request) {
   users := userService.SelectAllUser()
   framework.ResultJsonOk(w, users)
}

数据访问层

package dao

import (
    "micro-cloud/model"
    "fmt"
    )

type UserDao struct {
}

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)
    if err != nil {
        fmt.Println("Insert error")
        return
    }
    id, err := result.LastInsertId()
    if err != nil {
        fmt.Println("Insert error")
        return
    }
    return id
}

func (p *UserDao) SelectUserByName(username string) []model.User {
    rows, err := framework.DB.Query("SELECT * FROM user WHERE username = ?", username)
    if err != nil {
        fmt.Println("selectuserbyname error")
        return nil
    }
    var users []model.User
    for rows.Next() {
        var user model.User
        err := rows.Scan(&user.ID, &user.Username, &user.Password, &user.CreateTime)
        if err != nil {
            fmt.Println("selectuserbyname error")
            continue
        }
        users = append(users, user)
    }
    rows.Close()
    return users
}

func (p *UserDao) SelectAllUser() []model.User {
    rows, err := framework.DB.Query("SELECT * FROM user")
    if err != nil {
        fmt.Println("SelectAllUser error")
        return nil
    }
    var users []model.User
    for rows.Next() {
        var user model.User
        err := rows.Scan(&user.ID, &user.Username, &user.Password, &user.CreateTime)
        if err != nil {
            fmt.Println("SelectAllUser error")
            continue
        }
        users = append(users, user)
    }
    rows.Close()
    return users
}

实体层

package model

import "time"

type User struct {
    ID         uint      `json:"id"`
    Username   string    `json:"username"`
    Password   string    `json:"-"`
    CreateTime time.Time `json:"create_time"`
}

database

数据库操作类的实现

package microcloud

import (
    "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
var DB *sql.DB

func InitDB() {
    //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=True
    path := 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
    if err := DB.Ping(); err != nil {
        log.Panic(err)
    }
    log.Println("database connect success")
}

func CreateTable() {
    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)
    if err != nil {
        log.Panic(err)
    }
}

http

http server的实现

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

var mux = make(map[string]func(http.ResponseWriter,*http.Request))

func (p *RouterHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    fmt.Println(r.URL.Path)
    if fun, ok := mux[r.URL.Path]; ok {
        fun(w, r)
        return
    }
    //静态资源
    if strings.HasPrefix(r.URL.Path,constant.STATIC_BAES_PATH){
        if fun, 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。但是最主要的功能已经讲完了，感兴趣的可以从头编写下相关的代码。

完整例子下载：microcloud.rar