Golang Gorilla mux with http.FileServer returning 404

The problem I'm seeing is that I'm trying to use the http.FileServer with the Gorilla mux Router.Handle function.

This doesn't work (the image returns a 404)..

myRouter := mux.NewRouter()
myRouter.Handle("/images/", http.StripPrefix("/images/", http.FileServer(http.Dir(HomeFolder + "images/"))))

this works (the image is shown ok)..

http.Handle("/images/", http.StripPrefix("/images/", http.FileServer(http.Dir(HomeFolder + "images/"))))

Simple go web server program below, showing the problem...

package main

import (
    "fmt"
    "net/http"
    "io"
    "log"
    "github.com/gorilla/mux"
)

const (
    HomeFolder = "/root/test/"
)

func HomeHandler(w http.ResponseWriter, req *http.Request) {
    io.WriteString(w, htmlContents)
}

func main() {

    myRouter := mux.NewRouter()
    myRouter.HandleFunc("/", HomeHandler)
    //
    // The next line, the image route handler results in 
    // the test.png image returning a 404.
    // myRouter.Handle("/images/", http.StripPrefix("/images/", http.FileServer(http.Dir(HomeFolder + "images/"))))
    //
    myRouter.Host("mydomain.com")
    http.Handle("/", myRouter)

    // This method of setting the image route handler works fine.
    // test.png is shown ok.
    http.Handle("/images/", http.StripPrefix("/images/", http.FileServer(http.Dir(HomeFolder + "images/"))))

    // HTTP - port 80
    err := http.ListenAndServe(":80", nil)

    if err != nil {
        log.Fatal("ListenAndServe: ", err)
        fmt.Printf("ListenAndServe:%s\n", err.Error())
    }
}

const htmlContents = `<!DOCTYPE HTML>
<html lang="en">
  <head>
    <title>Test page</title>
    <meta charset = "UTF-8" />
  </head>
  <body>
    <p align="center">
        <img src="/images/test.png" height="640" width="480">
    </p>
  </body>
</html>
`

Solution

I posted this on golang-nuts discussion group and got this solution from Toni Cárdenas ...

The standard net/http ServeMux (which is the standard handler you are using when you use http.Handle) and the mux Router have different ways of matching an address.

See the differences between http://golang.org/pkg/net/http/#ServeMux and http://godoc.org/github.com/gorilla/mux.

So basically, http.Handle('/images/', ...) matches '/images/whatever', while myRouter.Handle('/images/', ...) only matches '/images/', and if you want to handle '/images/whatever', you have to ...

Option 1 - Use a regular expression match in your router

myRouter.Handle("/images/{rest}",
     http.StripPrefix("/images/", http.FileServer(http.Dir(HomeFolder + "images/"))))

Option 2 - Use the PathPrefix method on your router:

myRouter.PathPrefix("/images/").Handler(http.StripPrefix("/images/", 
     http.FileServer(http.Dir(HomeFolder + "images/"))))