Multipart form uploads in Go

upload.go

package upload

func Upload(w http.ResponseWriter, req *http.Request) {
	defer req.Body.Close()
	// Write straight to disk
	err := req.ParseMultipartForm(0)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)

		return
	}

	// We always want to remove the multipart file as we're copying
	// the contents to another file anyway
	defer func() {
		if remErr := req.MultipartForm.RemoveAll(); remErr != nil {
			// Log error?
		}
	}()

	// Get any form metadata you may want
  	myVar := req.FormValue("my_variable")

  	// Start reading multi-part file under id "fileupload"
	f, fh, err := req.FormFile("fileupload")
	if err != nil {
		if err == http.ErrMissingFile {
			http.Error(w, "Request did not contain a file", http.StatusBadRequest)
		} else {
			http.Error(w, err.Error(), http.StatusBadRequest)
		}

		return
	}
	defer f.Close()

	destDir, err := ioutil.TempDir("", "")
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)

		return
	}

	// Remove destDir in case of error
	defer func() {
		if err != nil {
			if remErr := os.RemoveAll(destDir); remErr != nil {
				// Log some kind of warning probably?
			}
		}
	}()

	// Create a file in our temporary directory with the same name
	// as the uploaded file
	destFile, err := os.Create(path.Join(destDir, fh.Filename))
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)

		return
	}
	defer destFile.Close()

	// Write contents of uploaded file to destFile
	if _, err = io.Copy(destFile, f); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)

		return
	}
}