大猩猩/多路复用器：图像不显示

Question

I am new in Golang. I need display an image. I tried using Gorilla/mux. But I am still getting Error:404. I thing may be the place where I used mux code is not correct.

Main func

    package main
    import (
        "net/http"
        "mytestsite/handlers"
         "log"
         "github.com/gorilla/mux"
     )


    func main() {

    r := mux.NewRouter()
    r.HandleFunc("/register", handlers.RegisterHandler)
    r.HandleFunc("/sucess", handlers.Sucess)
    r.HandleFunc("/login", handlers.Login)
    r.HandleFunc("/list", handlers.ViewList)
    r.HandleFunc("/logout", handlers.Logout)
    r.HandleFunc("/edit", handlers.Edit)
    r.HandleFunc("/EditnList", handlers.EditnList)
    r.HandleFunc("/notvalid", handlers.NotValid)
    r.HandleFunc("/delete", handlers.Delete)
    r.HandleFunc("/listchoose", handlers.ListChoose)
    r.HandleFunc("/email", handlers.SendEmail)
    images := http.StripPrefix("/images/", http.FileServer(http.Dir("./frontend/images/")))
    r.PathPrefix("/images/").Handler(images)

    if err := http.ListenAndServe(":8181", r); err != nil {
        log.Fatal("http.ListenAndServe: ", err)
    }        
}

Func which pass data to html

func ViewList(w http.ResponseWriter, r *http.Request) {
    viewModel:=viewmodels.RegisterViewModel{}
    user:=models.User{}
    dbResults := user.ViewDB() 

    //Cookies below
    cookieCheck := getCookie(r)

    if (cookieCheck != ""){
        err:=GetTemplate("list").Execute(w,dbResults)
        if err!=nil{
            panic(err)
        }
    } else { 
        viewModel.ErrorMessage="Please Enter Email Id and Password.."
        err:=GetTemplate("login").Execute(w,viewModel)
        if err!=nil{
            panic(err)
        }
    }
}

Usage in html file

<td><img src="{{.Photo}}" alt="{{.Photo}}" style="width:50px;height:50px;"/></td>

Value of {{.Photo}} is stored to Db by following code:

ctime := time.Now()
uploadedfile := "frontend/images"+ctime.Format("20060102150405")+".jpg"
out, err := os.Create(uploadedfile)

SO value of {{.Photo}} will be like as follows

frontend/images/20160202171411.jpg

Answer 1

You are mixing two routers here.

First off, the http package has a package global default handler called: DefaultServeMux. This is an instance of http.ServeMux

When you call http.HandleFunc, DefaultServeMux is where that handler gets registered (source)

When you call http.ListenAndServe, the second parameter is what handler to use for HTTP requests that come in on your specified port.

If you pass nil as the handler (like you do in your code), you are telling the http server to use http.DefaultServeMux

Gorilla mux is an alternative to http.ServeMux. In general, you use one or the other.

In your case, you are registering your file server with a gorilla mux, but then telling http.ListenAndServe to use http.DefaultServeMux (by omitting the handler).

You can either register your file serve with the standard http library's default mux (via: http.Handle) or change your function mappings to register with your Gorilla mux (via: r.HandlerFunc).

If you choose to use Gorilla (more flexible solution, but is not really necessary given your example code), then pass that instead of nil to ListenAndServe.