golangtc 源码阅读的启示

就像connect中间件一样要实现实现权限的检查，就把这个信息给带上建立一个 url,permission,handleFunc 的一张表，然后中间件就加在处理这张表的函数里。

比如url.go里面

/*
URL和Handler的Mapping
*/

package gopher

import (
"net/http"
)

type Handler struct {
URL         string
Permission  int
HandlerFunc http.HandlerFunc
}

var (
handlers = []Handler{
{"/", Everyone, indexHandler},
{"/about", Everyone, staticHandler("about.html")},
{"/faq", Everyone, staticHandler("faq.html")},
{"/timeline", Everyone, staticHandler("timeline.html")},
　　　　　　。。。。。。。。。
　　　　　　。。。。。。。。。

{"/books", Everyone, booksHandler},
{"/book/{id}", Everyone, showBookHandler},

{"/download", Everyone, downloadHandler},
}
)

然后再server.go里面

/*
读取配置文件,设置URL,启动服务器
*/

package gopher

import (
"fmt"
"log"
"net/http"

"github.com/gorilla/mux"
)

func handlerFun(handler Handler) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
if handler.Permission == Everyone {
handler.HandlerFunc(w, r)
} else if handler.Permission == Authenticated {
_, ok := currentUser(r)

if !ok {
http.Redirect(w, r, "/signin", http.StatusFound)
return
}

handler.HandlerFunc(w, r)
} else if handler.Permission == Administrator {
user, ok := currentUser(r)

if !ok {
http.Redirect(w, r, "/signin", http.StatusFound)
return
}

if !user.IsSuperuser {
message(w, r, "没有权限", "对不起，你没有权限进行该操作", "error")
return
}

handler.HandlerFunc(w, r)
}
}
}

func StartServer() {
http.Handle("/static/", http.FileServer(http.Dir(".")))
r := mux.NewRouter()
for _, handler := range handlers {
r.HandleFunc(handler.URL, handlerFun(handler))
}

http.Handle("/", r)

fmt.Println("Server start on:", Config.Port)
log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", Config.Port), nil))
}

然后用闭包，把中间件加上去。再用range handlers来对应路由。加中间件感觉就像是往上套一层一层的闭包。

func renderTemplate(w http.ResponseWriter, r *http.Request, file string, data map[string]interface{}) {
_, isPresent := data["signout"]

// 如果isPresent==true，说明在执行登出操作
if !isPresent {
// 加入用户信息
user, ok := currentUser(r)

if ok {
data["username"] = user.Username
data["isSuperUser"] = user.IsSuperuser
data["email"] = user.Email
data["fansCount"] = len(user.Fans)
data["followCount"] = len(user.Follow)
}
}

data["utils"] = utils

data["analyticsCode"] = analyticsCode
data["shareCode"] = shareCode
data["staticFileVersion"] = Config.StaticFileVersion
flash, _ := store.Get(r, "flash")
data["flash"] = flash
data["goVersion"] = goVersion

_, ok := data["active"]
if !ok {
data["active"] = ""
}

page := parseTemplate(file, data)
w.Write(page)
}

把负责view的render做成一个函数统一起来。

把download的内容配置成一个config里面的download文件，可以更好的管理要被下载的文件。