function httpGet(url)
  http.request(url)

  while true do
    local event, url, hBody = os.pullEvent()
    if event == "http_success" then
      return hBody
    elseif event == "http_failure" then
      error("Failed to HTTP GET " .. url)
      return nil
    end
  end
end

function processHttpBody(hBody, saveTo)
  if hBody then
    local body = hBody.readAll()
    local out = io.open(saveTo, "w")
    out:write(body)
    out:close()
    hBody.close()
    return 0
  else
    hBody.close()
    return 1
  end
end

function download(url, file)
  get = httpGet(url)
  if get then
    return processHttpBody(get, file)
  else
    return -1
  end
end