file_upload.go

func (s *Server) uploadFileHandler(w http.ResponseWriter, r *http.Request) {

	// Get the file from the request
	err := r.ParseMultipartForm(10 << 20)

	if err != nil {
		log.Println(err)
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	file, header, err := r.FormFile("file")
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	//set api key and secret api key in header

	buffer := &bytes.Buffer{}
	writer := multipart.NewWriter(buffer)
	log.Println(header.Filename)
	fw, err := writer.CreateFormFile("file", header.Filename)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// Copy the file data to the writer,
	// which will close the writer (deferred)
	n, err := io.Copy(fw, file)
	log.Println("size ", n)
	writer.Close()

	m := &sync.Mutex{}

	go func(writer *multipart.Writer, body *bytes.Buffer, m *sync.Mutex) {
		b, err := s.makePostRequestToPinata(writer, body)

		if err != nil {
			log.Println(err)
		}
		m.Lock()
		log.Println(string(b))
		// pinataResp <- b
		m.Unlock()

	}(writer, buffer, m)

	//make post request to pinata
	//write response body to response
	w.Header().Set("Content-Type", "application/json")
	w.Write([]byte(`{"message": "success, file is being uploaded"}`))

}

func (s *Server) makePostRequestToPinata(writer *multipart.Writer, body *bytes.Buffer) ([]byte, error) {
	//create request

	client := &http.Client{
		// Timeout: 30 * time.Second,
	}

	req, err := http.NewRequest("POST", s.Config.PinataBaseURL+s.Config.PinataUploadEndPoint, bytes.NewReader(body.Bytes()))
	if err != nil {
		return nil, err
	}
	// req.Header.Set("Content-Type", header.Header.Get("Content-Type"))
	req.Header.Set("pinata_api_key", s.Config.PinataAPIKey)
	req.Header.Set("pinata_secret_api_key", s.Config.PinataSecretAPIKey)
	req.Header.Set("Content-Type", writer.FormDataContentType())

	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	//read response body
	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	return b, nil
}