Golang构建简单web框架

妖狐艹你老母 2022-05-31 23:15 241阅读 0赞

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：

router.HandleFunc(“/login”, handlers.LoginHandler)

handler怎么写呢：

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),
        )
    })

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，比如测试，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))  
\}

执行命令行是这样的：

usage: beauty \[\] \[ …\]

A command-line tools of beauty.

Flags:  
–help Show context-sensitive help (also try –help-long and –help-man).

Commands:  
help \[…\]  
Show help.

demo  
Demo of web server.

generate

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！