CORS about fasthttprouter HOT 6 CLOSED

package main

import (
    "path"
    "strings"

    "github.com/buaazp/fasthttprouter"
    "github.com/valyala/fasthttp"
)

type CORS struct {
    origins map[string]bool
}

func (c *CORS) handler(h fasthttp.RequestHandler) fasthttp.RequestHandler {
    return func(ctx *fasthttp.RequestCtx) {
        if host := string(ctx.Host()); c.origins[host] {
            ctx.Response.Header.Set("Access-Control-Allow-Origin", host)
        }

        h(ctx)
    }
}

var (
    cors = &CORS{
        origins: map[string]bool{
            "127.0.0.1:8080": true,
        },
    }
)

func main() {
    routerPath := "/js/*filepath"        // router's path.
    filepath := path.Join("/path/to/js") // file's path

    // Create a file handler.
    fileHandler := fasthttp.FSHandler(filepath, strings.Count(routerPath[:len(routerPath)-10], "/"))

    router := fasthttprouter.New()
    // Wrapped by CORS handler.
    router.GET(routerPath, cors.handler(fileHandler))

    fasthttp.ListenAndServe(":8080", router.Handler)
}