问HTTP可下载文件服务

EN

 func SendFileToClient(w http.ResponseWriter,r *http.Request,file string){

    downloadBytes, err := ioutil.ReadFile(file)
    fmt.Println("file to be sent ",file)
    if err != nil {
        fmt.Printf("unable to download the file: %v", err)
    }

    mime := http.DetectContentType(downloadBytes)
    fileSize := len(string(downloadBytes))
   fmt.Println("mime is ",mime ," filesize ",fileSize)
    //Generate the server headers
    w.Header().Set("Content-Type", "octet-stream")
    w.Header().Set("Content-Disposition", "attachment; filename="+file+"")
    w.Header().Set("Expires", "0")
    w.Header().Set("Content-Transfer-Encoding", "binary")
    w.Header().Set("Content-Length", strconv.Itoa(fileSize))
    w.Header().Set("Content-Control", "private, no-transform, no-store, must-revalidate")


    
    //// force it down the client's.....
    http.ServeContent(w, r, file, time.Now(), bytes.NewReader(downloadBytes))



}