A rudimentary file and directory server

serve.go

/*  See other alternatives as well:
    https://github.com/rif/spark
    https://github.com/mholt/caddy
    https://github.com/GokulSrinivas/go-http
*/

package main

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

func main() {
	portPtr := flag.Int("p", 9090, "port to serve on")
	hostPtr := flag.String("h", "localhost", "hostname to use")
	filePtr := flag.String("f", "", "a particular file to serve")
	logPtr := flag.Bool("l", false, "display server access logs")

	flag.Parse()

	addr := fmt.Sprintf("%s:%d", *hostPtr, *portPtr)

	if *filePtr != "" {
		base := filepath.Base(*filePtr)
		url_pattern := "/" + base
		http.HandleFunc(url_pattern, FileHandler(*filePtr))
		log.Println("Serving file ", *filePtr)
		log.Printf("Please visit 'http://%s/%s' \n", addr, base)
	} else {
		dir := GetServeDir()
		http.Handle("/", http.FileServer(http.Dir(dir)))
		log.Println("Serving directory ", dir)
		log.Printf("Please visit 'http://%s/' \n", addr)
	}

	if *logPtr {
		log.Fatal(http.ListenAndServe(addr, Log(http.DefaultServeMux)))
	} else {
		log.Fatal(http.ListenAndServe(addr, nil))
	}

}

func FileHandler(file string) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, file)
	}
}

func GetServeDir() (dir string) {
	if flag.NArg() < 1 {
		cwd, err := os.Getwd()
		if err != nil {
			msg := "Please provide a directory argument to serve!"
			log.Fatal(msg)
		}
		dir = cwd
	} else {
		dir = flag.Arg(0)
	}
	return dir
}

func Log(handler http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		log.Printf("%s %s %s", r.RemoteAddr, r.Method, r.URL)
		handler.ServeHTTP(w, r)
	})
}