func (c Static) ServeDir(prefix, filepath string) revel.Result {
	prefix = c.Params.Fixed.Get("prefix")
	if prefix == "" {
		return c.NotFound("")
	}
	return serve(c, prefix, filepath, true)
}
This function serves out the directory as a browseable folder
package controllers
import (
	"os"
	fpath "path/filepath"
	"strings"
	"syscall"
	"fmt"
	"github.com/revel/modules/static/app/model"
	"github.com/revel/revel"
	"io/ioutil"
	"net/http"
)
type Static struct {
	*revel.Controller
}
const (
	B int64 = 1 << (10 * iota)  
	KB
	MB
	GB
	TB
	PB
	EB
)
var byteSizeList = [][]interface{}{
	{"B", B},
	{"KB", KB},
	{"MB", MB},
	{"GB", GB},
	{"TB", TB},
	{"EB", EB},
}
func (c Static) Serve(prefix, filepath string) revel.Result {
	prefix = c.Params.Fixed.Get("prefix")
	if prefix == "" {
		return c.NotFound("")
	}
	return serve(c, prefix, filepath, false)
}