Infinite redirect with Prefix in StaticOptions

[mattdavis90]

It looks as though #199 introduced a bug causing an infinite redirect when using StaticOptions.Prefix. This issue is around path.Clean and passing in ctx.req.URL.Path. I think this should be checked against opt.Prefix rather than "/" but this requires a special case when opt.Prefix == "" which is the fault.

Minimal example:

package main

import (
        "gopkg.in/macaron.v1"
        "net/http"
)

func main() {
        m := macaron.New()
        m.Use(macaron.Static("public", macaron.StaticOptions{
                Prefix: "/public",
        }))
        srv := &http.Server{
                Addr:    "0.0.0.0:8000",
                Handler: m,
        }
        srv.ListenAndServe()
}

Put an index.html in the public directory and navigate to http://127.0.0.1:8000/public you should get served the index.html but instead will get an infinite redirect to /public/.

[mattdavis90]

I think changing line 153 in static.go to the following works.

if !strings.HasSuffix(redirPath, opt.Prefix) {

[humaidq]

I think changing line 153 in static.go to the following works.

if !strings.HasSuffix(redirPath, opt.Prefix) {

This breaks other tests, I have tried other variations with similar results.