Go port of https://github.com/moserrya/knod

gnod.go

package main

import (
	"flag"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"path"
)

var (
	dir      = flag.String("dir", "", "Root directory to serve")
	port     = flag.Int("port", 8080, "Port to serve on")
	readonly = flag.Bool("readonly", false, "If true, only read operations will be supported")
)

func main() {
	flag.Parse()

	if *readonly {
		http.Handle("/", http.FileServer(http.Dir(*dir)))
	} else {
		http.Handle("/", http.StripPrefix("/", http.HandlerFunc(handler)))
	}
	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", *port), nil))
}

func handler(w http.ResponseWriter, r *http.Request) {
	path := path.Join(*dir, r.URL.Path)
	switch r.Method {
	case "GET":
		log.Printf("serving %s", path)
		f, err := os.Open(path)
		if err != nil {
			handleError(w, err)
			return
		}
		defer f.Close()
		io.Copy(w, f)
	case "DELETE":
		log.Printf("deleting %s", path)
		if err := os.Remove(path); err != nil {
			handleError(w, err)
			return
		}
	case "PUT", "POST":
		log.Printf("updating %s", path)
		f, err := os.Create(path)
		if err != nil {
			handleError(w, err)
			return
		}
		defer f.Close()
		defer r.Body.Close()
		io.Copy(f, r.Body)
	case "HEAD":
		fi, err := os.Stat(path)
		if err != nil {
			handleError(w, err)
			return
		}
		w.Header().Set("Content-length", fmt.Sprintf("%d", fi.Size()))
	default:
		http.Error(w, r.Method+" not supported", http.StatusMethodNotAllowed)
	}
}

func handleError(w http.ResponseWriter, err error) {
	switch err {
	case os.ErrPermission:
		http.Error(w, err.Error(), http.StatusForbidden)
	case os.ErrNotExist:
		http.Error(w, err.Error(), http.StatusNotFound)
	default:
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}