【golang】HTTP服务器的request互相传递数据

context:上下文，不仅可以设置超时控制Goroutine，还可在上下文中进行传值

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/", mid(home))

    mux.HandleFunc("/login", login)

    log.Fatal(mux.ListenAndServe(":8099", mux))

}

func home(w http.ResponseWriter, r *http.Request) {
    name := r.Context().Value("name")
    fmt.Fprintf(w, "%s\n", name)
}

func login(w http.ResponseWriter, r *http.Request) {
    if r.URL.Query().Get("user") != "root" {
        http.Error(w, http.StatusText(401), 401)
        return
    }
    cookie := &http.Cookie{Name: "Test"}
    http.SetCookie(w, cookie)
    http.Redirect(w, r, "/", 302)
}

func mid(next http.HandlerFunc) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        cookie, err := r.Cookie("Name")

        if err != nil || cookie == nil {
            http.Error(w, http.StatusText(401), 401)
            return
        }
        next(w, r.WithContext(context.WithValue(r.Context(), "Name", cookie)))
    }

}