go-calc-remote-handler.go

func remoteHandler(client HTTPClient) http.HandlerFunc {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		url := r.URL.Query().Get("url")
		if url == "" {
			url = "http://example.com/"
		}

		req, err := http.NewRequest(http.MethodPost, url, r.Body)
		if err != nil {
			log.Println(err)
			response := NewErrorResponse(err)
			writeBody(w, r, response, http.StatusInternalServerError)
			return
		}

		res, err := client.Do(req)
		if err != nil {
			log.Println(err)
			response := NewErrorResponse(err)
			writeBody(w, r, response, http.StatusInternalServerError)
			return
		}
		defer res.Body.Close()

		body, err := ioutil.ReadAll(res.Body)
		if err != nil {
			log.Println(err)
			response := NewErrorResponse(err)
			writeBody(w, r, response, http.StatusInternalServerError)
			return
		}

		if res.StatusCode != http.StatusOK {
			err := fmt.Errorf("remote call failed, returned status code %d", res.StatusCode)
			log.Println(err)
			response := NewErrorResponse(err)
			writeBody(w, r, response, http.StatusInternalServerError)
			return
		}

		writeRawBody(w, req, body, http.StatusOK)
	})
}