Is it possible to implement an analogue of proxy_pass nginx in golang?

Question

go

Nginx is very cool at proxying requests and downloading files, but the problem is to authorize these requests and change urls dynamically.

But it’s enough to write

location /start {
            proxy_pass http://kinosotik.com/download/malenqkie-chudoviwa?original;
        }

And nginx will download a file from a remote site immediately after clicking on the link, it supports resume, etc.

Trying to write something similar in golang, but it gives a 404 error

func main() {
   http.HandleFunc("/", handlerProxy)
   if err := http.ListenAndServe(":4000", nil); err != nil {
       panic(err)
   }
}

func handlerProxy(w http.ResponseWriter, r *http.Request) {
   fmt.Println(r.URL.Host)

   url, _ := url.Parse(fmt.Sprintf("http://kinosotik.com/download/malenqkie-chudoviwa?original"))

    r.Host = url.Host
    r.URL.Scheme = "http"

   proxy := httputil.NewSingleHostReverseProxy(url)
   fmt.Println(r.URL.Host)

   proxy.ServeHTTP(w, r)
}

Answer 1

to have no buffer, you need this piece

body, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        http.Error(w, "error reading response body", http.StatusInternalServerError)
        return
    }

    // write status code and body from proxy request into the answer
    w.WriteHeader(resp.StatusCode)
    w.Write(body)

replace with this one:

w.WriteHeader(resp.StatusCode)
_, err := io.Copy(w, body)
if err != nil {
    http.Error(w, "error reading response body", http.StatusInternalServerError)
    return
}