实现简单go web框架

2017-07-04

FLYING
使用Golang构建web服务还是比较简单的，使用net/http和gorilla/mux就能快速的构建一个简易的web server

package main
import {
    "net/http"
    "github.com/gorilla/mux"
}
func main() {
    router = mux.NewRouter().StrictSlash(true)
    router.Handle("/", http.FileServer(http.Dir("/static")))
    http.ListenAndServe(":8080", nil)
}

这样一个简易的静态服务器就构建成功了。

当然我们不可能就这么满足了，我们当然希望这个服务器是可以处理一些业务逻辑的。比如登录：

1	router.HandleFunc("/login", handlers.LoginHandler)

handler怎么写呢：

1
2
3

func LoginHandler(w http.ResponseWriter, r *http.Request) {
    controllers.LoginIndexAction(w,r);
}

controller(使用mymysql连接数据库)：

func LoginAction(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("content-type", "application/json")
    err := r.ParseForm()
    if err != nil {
        Response(w, "Param error.", "PARAM_ERROR",403)
        return
    }
    admin_name      := r.FormValue("admin_name")
    admin_password  := r.FormValue("admin_password")
    if admin_name == "" || admin_password == ""{
        Response(w, "Param error.", "PARAM_ERROR",403)
        return
    }
    db := mysql.New("tcp", "", "127.0.0.1:3306", "user", "pass", "database")
    if err := db.Connect(); err != nil {
        log.Println(err)
        Response(w, "Param error.", "PARAM_ERROR",403)
        return
    }
    defer db.Close()
    rows, res, err := db.Query("select * from webdemo_admin where admin_name = '%s'", admin_name)
    if err != nil {
        log.Println(err)
        Response(w, "Database error.", "DATABASE_ERROR",503)
        return
    }
    name := res.Map("admin_password")
    admin_password_db := rows[0].Str(name)
    if admin_password_db != admin_password {
        Response(w, "Password error.", "PASSWORD_ERROR",403)
        return
    }
    cookie := http.Cookie{Name: "admin_name", Value: rows[0].Str(res.Map("admin_name")), Path: "/"}
    http.SetCookie(w, &cookie)
    Response(w, "Login success.", "SUCCESS",200)
    return
}
type response struct{
    Status int `json:"status"`
    Description string `json:"description"`
    Code string `json:"code"`
}
func Response(w http.ResponseWriter, description string,code string, status int) {
    out := &response{status, description, code}
    b, err := json.Marshal(out)
    if err != nil {
        return
    }
    w.WriteHeader(status)
    w.Write(b)
}

将用户名放到cookie里就当登录成功了。

如果有多个路由需要处理呢，情形就会变成这样：

router.HandleFunc("/url1", handlers.Handler1)
router.HandleFunc("/url2", handlers.Handler1)
router.HandleFunc("/url3", handlers.Handler1)
router.HandleFunc("/url4", handlers.Handler1)
router.HandleFunc("/url5", handlers.Handler1)
router.HandleFunc("/url6", handlers.Handler1)
router.HandleFunc("/url7", handlers.Handler1)
...

好像也无伤大雅，但是如果有更一步的需求，每个URL需要做权限验证，记录日志，这种方式显然就不太合理了，我们需要对router做统一的管理，这里我们跳过了handler层，直接由controller来处理，我觉得更简洁一点。

//先定义Route的结构体
type Route struct {
	Name        string
	Method      string
	Pattern     string
	Auth		bool
	HandlerFunc http.HandlerFunc
}
type Routes []Route
var routes = Routes{
	Route{
		"url1",
		"GET",
		"/url1",
		true,
		controllers.Url1,
	},
	Route{
		"url2",
		"POST",
		"/url2",
		false,
		controllers.Url2,
	},
}
var router *mux.Router
func NewRouter() *mux.Router {
        if router == nil {
                router = mux.NewRouter().StrictSlash(true)
        }
	for _, route := range routes {
		router.
			Methods(route.Method).
			Path(route.Pattern).
			Name(route.Name).
			Handler(route.HandlerFunc)
	}
	return router
}

这时候如果添加权限验证，只有通过登录验证的用户才有权限调用，这就需要中间件（我个人比较喜欢称它装饰器）出场了：

func Auth(inner http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	    cookie, err := r.Cookie("admin_name")
	    if err != nil || cookie.Value == ""{
	        Response(w, "token not found.", "AUTH_FAILED",403)
	        return;
	    }
	    rows, res, err := db.Query("select * from user where user_name= '%d'", cookie.Value)
	    if err != nil {
	        Response(w, "can not connect database.", "DB_ERROR",500)
	        return
	    }
	    if len(rows) == 0 {
	    	Response(w, "user not found.", "NOT_FOUND",404)
	    	return
	    }
	    row := rows[0]
	    user := controllers.User{
	    		User_id:row.Int(res.Map("user_id")), 
	    		User_name:row.Str(res.Map("user_name")),
	    		User_type:row.Str(res.Map("user_type")),
	    		Add_time:row.Str(res.Map("add_time"))}
	    session.CurrentUser = user
	    log.Printf("user_id:%v",controllers.CurrentUser.User_id)
	    inner.ServeHTTP(w, r)
	})
}
func NewRouter() *mux.Router {
	if router == nil {
                router = mux.NewRouter().StrictSlash(true)
        }
	for _, route := range routes {
		if(route.Auth){
			handler = decorates.Auth(route.HandlerFunc)
		}
		router.
			Methods(route.Method).
			Path(route.Pattern).
			Name(route.Name).
			Handler(handler)
	}
	return router
}

显然这样管理session是比较粗糙的，怎么办，有现成的解决方案，jwt(JSON Web Tokens)，我们可以使用jwt-go来生成token，如果一个请求cookie或者header里面含有token，并且可以验证通过，我就认为这个用户是合法用户：

//生成token
func Generate(key string) (string, error) {
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"key": key,
		"exp": (time.Now().Add(time.Minute * 60 * 24 * 2)).Unix(),
	})
	tokenString, err := token.SignedString(settings.HmacSampleSecret)
	return tokenString, err
}
//验证token
func Valid(tokenString string) (string, error) {
	token1, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("Unexpected signing method: %v", token.Header["alg"])
		}
		return settings.HmacSampleSecret, nil
	})
	if claims, ok := token1.Claims.(jwt.MapClaims); ok && token1.Valid {
		return fmt.Sprintf("%v", claims["key"]), nil
	} else {
		return "", err
	}
}

Auth中间件就可以变成下面的样子：

func Auth(inner http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	    cookie, err := r.Cookie("token")
	    if err != nil || cookie.Value == ""{
	        Response(w, "token not found.", "AUTH_FAILED",403)
	        return;
	    }
	    user_id, err := token.Valid(cookie.Value)
	    if err != nil {
	        Response(w, "bad token.", "AUTH_FAILED",403)
	        return;
	    }
	    rows, res, err := db.Query("select * from user where user_id= '%d'", user_id)
	    if err != nil {
	        Response(w, "can not connect database.", "DB_ERROR",500)
	        return
	    }
	    if len(rows) == 0 {
	    	Response(w, "user not found.", "NOT_FOUND",404)
	    	return
	    }
	    row := rows[0]
	    user := controllers.User{
	    		User_id:row.Int(res.Map("user_id")), 
	    		User_name:row.Str(res.Map("user_name")),
	    		User_type:row.Str(res.Map("user_type")),
	    		Add_time:row.Str(res.Map("add_time"))}
	    session.CurrentUser = user
	    log.Printf("user_id:%v",controllers.CurrentUser.User_id)
	    inner.ServeHTTP(w, r)
	})
}

我们还可以对每个URL实现log记录：

func Logger(inner http.Handler, name string) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		start := time.Now()
		inner.ServeHTTP(w, r)
		log.Printf(
			"%s\t%s\t%s\t%s",
			r.Method,
			r.RequestURI,
			name,
			time.Since(start),
		)
	})
}
func NewRouter() *mux.Router {
	if router == nil {
                router = mux.NewRouter().StrictSlash(true)
        }
	for _, route := range routes {
		var handler http.Handler = decorates.Logger(route.HandlerFunc, route.Name)
		if(route.Auth){
			handler = decorates.Auth(handler)
		}
		router.
			Methods(route.Method).
			Path(route.Pattern).
			Name(route.Name).
			Handler(handler)
	}
	return router
}

有跨域的需求？好办：

func CorsHeader(inner http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    	    w.Header().Set("Access-Control-Allow-Origin", r.Header.Get("Origin"))
    	    w.Header().Set("Access-Control-Allow-Credentials", "true")
	    w.Header().Add("Access-Control-Allow-Method","POST, OPTIONS, GET, HEAD, PUT, PATCH, DELETE")
	    w.Header().Add("Access-Control-Allow-Headers","Origin, X-Requested-With, X-HTTP-Method-Override,accept-charset,accept-encoding , Content-Type, Accept, Cookie")
    	    w.Header().Set("Content-Type","application/json")
		inner.ServeHTTP(w, r)
	})
}
func NewRouter() *mux.Router {
	if router == nil {
        router = mux.NewRouter().StrictSlash(true)
    }
	for _, route := range routes {
		var handler http.Handler = decorates.Logger(route.HandlerFunc, route.Name)
		if(route.Auth){
			handler = decorates.Auth(handler)
		}
		handler = decorates.CorsHeader(handler)
		router.
			Methods(route.Method).
			Path(route.Pattern).
			Name(route.Name).
			Handler(handler)
		router.
			Methods("OPTIONS").
			Path(route.Pattern).
			Name("cors").
			Handler(decorates.CorsHeader(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				return
			})))
	}
	return router
}

session管理好像还有一些问题，每个request请求都会改变全局的CurrenUser，如果有并发的情况下，这就容易产生混乱了，可以需要用户信息的时候通过token去数据库来取，效率会有影响，但并发的问题可以解决了：

func CurrentUser(r *http.Request) *models.User {
	cookie, err := r.Cookie("token")
	if err != nil || cookie.Value == "" {
		return &models.User{}
	}
	key, err := token.Valid(cookie.Value)
	if err != nil {
		return &models.User{}
	}
	if !strings.Contains(key, "|") {
		return &models.User{}
	}
	keys := strings.Split(key, "|")
	rows, res, err := db.QueryNonLogging("select * from user where user_id = '%v' and user_pass = '%v'", keys[0], keys[1])
	if err != nil {
		return &models.User{}
	}
	if len(rows) == 0 {
		return &models.User{}
	}
	row := rows[0]
	user := models.User{
		User_id:   row.Int(res.Map("user_id")),
		User_name: row.Str(res.Map("user_name")),
		User_type: row.Str(res.Map("user_type")),
		Add_time:  row.Str(res.Map("add_time"))}
	return &user
}

日志的问题好像还没有解决，毕竟日志需要写到文件里面并且需要一些详细的信息，比如行号，文件，才能利于排查问题，或者做统计：

func Printf(format string, params ...interface{}) {
	_, f, line, _ := runtime.Caller(1)
	log.Printf(format, params...)
	file, err := os.OpenFile(settings.LogFile, os.O_CREATE|os.O_APPEND|os.O_RDWR, os.ModePerm)
	if err != nil {
		log.Printf("%v", err)
		return
	}
	defer file.Close()
	_, err = file.Seek(0, os.SEEK_END)
	if err != nil {
		return
	}
	args := strings.Split(f, "/")
	f = args[len(args)-1]
	msg := fmt.Sprintf("%v:%v(%v)", line, format, f)
	logger := log.New(file, "", log.LstdFlags)
	logger.Printf(msg, params...)
}
func Println(v ...interface{}) {
	_, f, line, _ := runtime.Caller(1)
	log.Println(v...)
	file, err := os.OpenFile(settings.LogFile, os.O_CREATE|os.O_APPEND|os.O_RDWR, os.ModePerm)
	if err != nil {
		log.Printf("%v", err)
		return
	}
	defer file.Close()
	_, err = file.Seek(0, os.SEEK_END)
	if err != nil {
		return
	}
	args := strings.Split(f, "/")
	f = args[len(args)-1]
	msg := fmt.Sprintf("%v:%v(%v)", line, fmt.Sprintln(v...), f)
	logger := log.New(file, "", log.LstdFlags)
	logger.Println(msg)
}

日志写到文件的问题解决了，又面临新的问题，日志文件太大，怎么办，需要归档（每隔12小时就查看一下日志文件多大了，如果太大了就压缩一下归档）：

var ticker = time.NewTicker(time.Minute * 60 * 12)
func init() {
	go func() {
		for _ = range ticker.C {
			archive()
		}
	}()
}
func archive() error {
	info, _ := os.Stat(settings.LogFile)
	if info.Size() > 1024*1024*50 {
		target := fmt.Sprintf("%v.%v.tar.gz",
			shortFileName(settings.LogFile),
			time.Now().Format("2006-01-02-15-04"),
		)
		tmp := fmt.Sprintf("%v.%v.tmp",
			shortFileName(settings.LogFile),
			time.Now().Format("2006-01-02-15-04"),
		)
		in := bytes.NewBuffer(nil)
		cmd := exec.Command("sh")
		cmd.Stdin = in
		go func() {
			in.WriteString(fmt.Sprintf("cd %v\n", shortFileDir(settings.LogFile)))
			in.WriteString(fmt.Sprintf("cp %v %v\n", shortFileName(settings.LogFile), tmp))
			in.WriteString(fmt.Sprintf("echo '' > %v\n", shortFileName(settings.LogFile)))
			in.WriteString(fmt.Sprintf("tar -czvf %v %v\n", target, tmp))
			in.WriteString(fmt.Sprintf("rm %v\n", tmp))
			in.WriteString("exit\n")
		}()
		if err := cmd.Run(); err != nil {
			fmt.Println(err)
			return err
		}
	}
	return nil
}

基本的功能好像都能解决了，饱暖思淫欲，错误处理感觉用起来不怎么舒服，有更优雅的办法：

type Handler func(http.ResponseWriter, *http.Request) *models.APPError
func (fn Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if e := fn(w, r); e != nil {
		utils.Response(w, e.Message, e.Code, e.Status)
	}
}
//装饰器就变成了这样
func (inner Handler) Auth() Handler {
	return Handler(func(w http.ResponseWriter, r *http.Request) *models.APPError {
		tokenString := ""
		cookie, _ := r.Cookie("token")
		if cookie != nil {
			tokenString = cookie.Value
		}
		if tokenString == "" {
			if r.Header != nil {
				if authorization := r.Header["Authorization"]; len(authorization) > 0 {
					tokenString = authorization[0]
				}
			}
		}
		key, err := token.Valid(tokenString)
		if err != nil {
			return &models.APPError{err, "bad token.", "AUTH_FAILED", 403}
		}
		if !strings.Contains(key, "|") {
			return &models.APPError{err, "user not found.", "NOT_FOUND", 404}
		}
		keys := strings.Split(key, "|")
		rows, _, err := db.QueryNonLogging("select * from user where user_id = '%v' and user_pass = '%v'", keys[0], keys[1])
		if err != nil {
			return &models.APPError{err, "can not connect database.", "DB_ERROR", 500}
		}
		if len(rows) == 0 {
			return &models.APPError{err, "user not found.", "NOT_FOUND", 404}
		}
		go log.Printf("user_id:%v", keys[0])
		inner.ServeHTTP(w, r)
		return nil
	})
}
//router画风也变了
type Route struct {
	Name        string
	Method      string
	Pattern     string
	HandlerFunc Handler
	ContentType string
}
type Routes []Route
var BRoutes = Routes{
	Route{
		"nothing",
		"GET",
		"/",
		Config,
		contenttype.JSON,
	},
	Route{
		"authDemo",
		"GET",
		"/demo1",
		Handler(Config).
			Auth(),
		contenttype.JSON,
	},
	Route{
		"verifyDemo",
		"GET",
		"/demo2",
		Handler(Config).
			Verify(),
		contenttype.JSON,
	},
	Route{
		"verifyAndAuthDemo",
		"GET",
		"/demo3",
		Handler(Config).
			Auth().
			Verify(),
		contenttype.JSON,
	},
}

这样基本的web框架就完成了，想添加一些命令行工具，比如自动生成app，推荐用kingpin来实现：

var (
	app      = kingpin.New("beauty", "A command-line tools of beauty.")
	demo     = app.Command("demo", "Demo of web server.")
	generate = app.Command("generate", "Generate a new app.")
	name     = generate.Arg("name", "AppName for app.").Required().String()
)
func main() {
	switch kingpin.MustParse(app.Parse(os.Args[1:])) {
	case generate.FullCommand():
		GOPATH := os.Getenv("GOPATH")
		appPath := fmt.Sprintf("%v/src/%v", GOPATH, *name)
		origin := fmt.Sprintf("%v/src/github.com/yang-f/beauty/etc/demo.zip", GOPATH)
		dst := fmt.Sprintf("%v.zip", appPath)
		_, err := utils.CopyFile(dst, origin)
		if err != nil {
			fmt.Println(err.Error())
		}
		utils.Unzip(dst, appPath)
		os.RemoveAll(dst)
		helper := utils.ReplaceHelper{
			Root:    appPath,
			OldText: "{appName}",
			NewText: *name,
		}
		helper.DoWrok()
		log.Printf("Generate %s success.", *name)
	case demo.FullCommand():
		log.Printf("Start server on port %s", settings.Listen)
		router := router.NewRouter()
		log.Fatal(http.ListenAndServe(settings.Listen, router))
	}
}

执行beauty命令是这样的：

usage: beauty [<flags>] <command> [<args> ...]
A command-line tools of beauty.
Flags:
  --help  Show context-sensitive help (also try --help-long and --help-man).
Commands:
  help [<command>...]
    Show help.
  demo
    Demo of web server.
  generate <name>
    Generate a new app.

到此，这个框架还在不断的优化中，希望能有人提供宝贵的批评和建议。

以下是代码地址：

yang-f/beauty

谢谢！