RPC4Minetest

function rpc.call(url, method, ...)
  local JSONRequestArray = {
    id=tostring(math.random()),
    ["method"]=method,
    params = ...
  }
  local jsonRequest = minetest.write_json(JSONRequestArray)
  local httpResponse = http.fetch_async_get(
    http.fetch_async(
        { ['url'] = url,
          method = 'POST',
          extra_headers = { ['content-type']='text/plain', ['content-length']=string.len(jsonRequest) },
          post_data = jsonRequest
       }
    )
  )
  -- Check the http response code
  if (httpResponse.code~=200) then
     return nil, "HTTP ERROR: " .. httpResponse.code
  end

  return minetest.parse_json(httpResponse.data).result, nil
end