Getting snapshot from motion with nginx openresty content_by_lua

motion.snapshots.nginxconf

  location /snapshot {
     content_by_lua '
         local host = "127.0.0.1"
         local port = 8001
         local sock = ngx.socket.tcp()
         local ok, err = sock:connect(host, port)
         bytes, err  = sock:send("GET /\\r\\nHost: "..host..":"..port.."\\r\\n\\r\\n")
         if not ok then
             ngx.say("Request error ", err)
             return
         end
         ngx.header.content_type = "text/html"
         if not ok then
             ngx.say("Connection error ", err)
             return
         end
         local data = ""
         while true do
           local chunk, err = sock:receive(256)
           if err then
             ngx.say("Reading error ", string.len(data))
             return
           end
           data = data .. chunk
           local match = string.match(data, "\\r\\n[-][-]BoundaryString\\r\\n.-\\r\\n\\r\\n(.-)\\r\\n[-][-]BoundaryString\\r\\n")
           if match then
             ngx.header.content_type = "image/jpeg"
             ngx.say(match)
             return
           end
         end
     ';
  }

Hi @imbalind, sorry for delay, I've completely missed your message.
string.len(data) == 0 means that script haven't received any data. Looks like it is problem with your Motion.