fp MQTT with user/password support ?

[PaulRowntree]

Hi!I have been looking for a Laz/fp MQTT package that will connect to an external MQTT broker; this requires that the package support username and password fields.  The codes that I have seen most often (Delphi ported code by Jamie Ingilby, modified by ZiCog, then modified by heX) [ https://github.com/heX16/mqtt-free-pascal/blob/master/TMQTTClient/MQTT.pas ] does not support these fields, although it looks like some initial code was started in this direction (VariableHeaderConnect ) but not completed and not actually used in the main code.
Does anyone know of a functioning fp MQTT package with this capability? 
Thanks!

[DonAlfredo]

Have a look at the MQTT connect specs:
https://www.hivemq.com/blog/mqtt-security-fundamentals-authentication-username-password

You see that you can add a username and password into this connection request.

Example:

Code: Pascal  [Select][+][-]

1. FH := FixedHeader(MQTT.CONNECT, 0, 0, 0);
2. VH := VariableHeaderConnect(40);
3. SetLength(Payload, 0);
4. AppendArray(Payload, StrToBytes(FClientID, true));
5. AppendArray(Payload, StrToBytes('username', true));
6. AppendArray(Payload, StrToBytes('password', true));
7. RL := RemainingLength(Length(VH) + Length(Payload));
8. Data := BuildCommand(FH, RL, VH, Payload);
9.  

[PaulRowntree]

Hi DonAlfredo, and thank you!  Yes, that is the general way to do it. There are also 2 bits that need to be set in the FixedHeader, and I will try this tonight.  Oddly, all versions of the Delphi-forked MQTT code have this in the ReadThread connect code,

 //  Build CONNECT message
          FH := FixedHeader(MQTT.CONNECT, 0, 0, 0);
          VH := VariableHeaderConnect(40);
          SetLength(Payload, 0);
          AppendArray(Payload, StrToBytes(FClientID, True));
          AppendArray(Payload, StrToBytes('lwt', True));           
          AppendArray(Payload, StrToBytes(FClientID + ' died', True));

          RL := RemainingLength(Length(VH) + Length(Payload));
          Data := BuildCommand(FH, RL, VH, Payload);
(BOLD sections highlighted by me) It looks like 'lwt' and FClientID+' died' are hard-coded Will topic/message information to be sent if the connection dies.  Does everyone use this same topic/message, or is this a vestigial bit of code?

[PaulRowntree]

Setting the special bits, and appending fields as DonAlfredo suggested, works like a charm. 

Will share code if anyone is interested.Thanks!

[Anders Gustav]

...

Will share code if anyone is interested.Thanks!

Indeed I am!