How to serve a file to a specific url path with the FileServer function in go/golang

Question

I need to serve an html file to localhost:8080/lvlione but the FileServer function in golang doesn't seem to work.

Here is main.go:

package main

import (
    "log"      //logging that the server is running and other stuff
    "net/http" //serving files and stuff
)

func main() {
    //servemux
    server := http.NewServeMux()

    //handlers that serve the home html file when called
    fs := http.FileServer(http.Dir("./home"))
    os := http.FileServer(http.Dir("./lvlone")) //!!this is what is broken!!

    //handles paths by serving correct files
    //there will be if statements down here that check if someone has won or not soon
    server.Handle("/", fs)
    server.Handle("/lvlione", os)

    //logs that server is Listening
    log.Println("Listening...")
    //starts server
    http.ListenAndServe(":8080", server)
}

There is a folder in this directory called lvlone with one file in it (index.html). When I point my browser to localhost:8080/lvlione it returns 404 , but when it is pointed to localhost:8080 it returns the correct file.

Answer 1

You need to call http.StripPrefix to remove the extra lvlone from the directory path.

      server.Handle("/lvlone/", http.StripPrefix("/lvlone/", os))

By default the http.FileServer assumes the path given to it is the root path, and appends the URL to it. If it is to serve a subdirectory of the virtual path, then that needs to be stripped from the path.

And note that you need to have the trailing slashes in both places.