Simple go script to handle downloading files

downloader.go

package main

import (
  "net/http"
  "log"
  "os"
  "io"
  "strconv"
)

func main() {
  http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
    Filename := request.URL.Query().Get("file")
    OpenFile, err := os.Open(FileName)
    if err != nil {
      http.Error(w, "no file", 404)
    }

    FileHeader := make([]byte, 1024)
    OpenFile.Read(FileHeader)
    FileContentType := http.DetectContentType(FileHeader)

    FileStat, _ := OpenFile.Stat()
    FileSize := strconv.FormatInt(FileStat.Size(), 10)

    w.Header().Set("Content-Disposition", "attachment; filename=" + FileName)
    w.Header().Set("Content-Type", FileContentType)
    w.Header().Set("Content-Length", FileSize)

    OpenFile.Seek(0, 0)
    io.Copy(w, OpenFile)
    return
  });

  err := http.ListenAndServe(":8080", nil)
  if err != nil {
    log.Fatal("ListenAndServe: ", err)
  }
}