Implemented from sgcWebSockets 4.1.4

Supported by:

  TsgcWebSocketServer

  TsgcWebSocketHTTPServer

  TsgcWebSocketClient

 

WebSocket provides a simple subprotocol negotiation, basically adds a header with protocols name supported by request, this protocols are received and if receiver supports one of them, sends a response with subprotocol supported.

sgcWebSockets supports several SubProtocols: MQTT, WAMP... and more. You can implement your own subprotocols using a very easy method, just call RegisterProtocol and send SubProtocol Name as argument.

Example: you need to connect to a server which implements subprotocol "Test 1.0"

Client.Host := server host;

Client.Port := server.port;

Client.RegisterProtocol('Test 1.0');

Client.Active := True;

 

 

When a client sends a binary message to server, sometimes is useful set an ID to identify binary message when is received. There are 2 functions in sgcWebSocket_Helpers which can be used to set a short description of binary packet, basically adds a header to stream which is used to identify binary packet.

 

Before send a binary message, call sgcWSStreamWrite method to encode stream.

   vID := '00001';

   sgcWSStreamWrite(vID, oStream);

   Client.WriteData(oStream);

 

When binary message is received, call sgcWSStreamRead method to decode stream.

   sgcWSStreamRead(oStream, vID);

 

The only limitation is that text used to identify binary message, has a maximum length of 10 characters (this can be modified if you have access to source code).