Why does PacketPeerStream send extra data?

system · May 29, 2018, 6:35pm


	Attention	Topic was automatically imported from the old Question2Answer platform.
	Asked By	AngelOnFira

I’m working on a multiplayer game in which the clients will connect to a Python server. I’m after connecting to the server with

var connection = StreamPeerTCP.new()
var wrapped_client = PacketPeerStream.new()
connection.connect_to_host( ip, port )
wrapped_client.set_stream_peer(connection)

And then sending data with

wrapped_client.put_var("hi")

However, the python server receives

hi

As you can see, there is a prefix that seems to be null data. The hex representation of the data received on the server is as follows,

0c 20 20 20 04 20 20 20 02 20 20 20 68 69

This shows that there is a lot of excess data up until the last two bytes, which represent the characters “h” and “i”. What exactly is this data for? Is there any way to not send this excess information?

system · July 19, 2018, 4:53pm


	Reply From:	hungrymonkey

github.com

godotengine/godot/blob/e7cf2b2e77a097a026f883f003ad299b5d451885/core/io/packet_peer.cpp#L93


      
          
          	const uint8_t *buffer;
          	int buffer_size;
          	Error err = get_packet(&buffer, buffer_size);
          	if (err)
          		return err;
          
          	return decode_variant(r_variant, buffer, buffer_size, NULL, allow_object_decoding);
          }
          
          Error PacketPeer::put_var(const Variant &p_packet) {
          
          	int len;
          	Error err = encode_variant(p_packet, NULL, len, !allow_object_decoding); // compute len first
          	if (err)
          		return err;
          
          	if (len == 0)
          		return OK;
          
          	uint8_t *buf = (uint8_t *)alloca(len);

when you send a string down the network api, you are actually sending a variant.

according to the docs, the first 12 bytes are the header for the string.