Golang构建简单web框架

liuxinyang666 · · 1018 次点击 · · 开始浏览

这是一个创建于的文章，其中的信息可能已经有所发展或是发生改变。

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),
    )
})

}

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))
}