Hi. I got a new Raspberry Pi 4 and installed Lazarus 2.0.2 on it. Took ssome time but I got all the packges installed and the IDE rebuild.

I compile the mqttclient app.

But as soon as I open it I get this error.

It seems it is coming from the LNet package.

Hi Bond
Followed your readme to compile but file passwordman.pas uses StreamUtils which is not in your lazarus repo. Where can I find this file or will you add it?

Petr

Hi.

I am confused. I installed a clean copy of Lazarus 1.8.
I tried to install your components but it is looking for iNet Visual.

Where do I get that? You state you are using LNet so I am a bit confused at this stage.

Regards.

Hi,
Tryed to compile mqttclient.pas but it throws an error about missing units Buffers.pas and Logging.pas
Where are they located?

best regards,
Stefan

There is a memory leak where QoS1 and QoS2 PUBLISH packets received by the client and server are not being freed. QoS0 packets are fine.

Documentation is being generated using Lazarus FPDocs. The source for the docs is in the docs directory. It needs to be fleshed out a little. A good way for someone to learn the code.

MQTTServer.pas needs to be updated

Should be modified so that an array of words isn't being stored in a TList object. Typecasting pointers to Words is not portable and could cause problems down the road. I was thinking it should be a list of pointers to words that are dynamically allocated as needed.

Apparently validation was done in ReadFromBuffer and WriteToBuffer

Provide for logging output to a file in the CLI server application

It would be better if client subscriptions could be stored in the lfm file rather than having to add them during the InitSession event handler.

The existing Client.Subscriptions property uses an object list and isn't really all that useful.

Change the TMQTTClient component to use a TCollectionItem for storing Subscriptions instead.

Remove the OnSubscriptionsChanged event handler, which was not really useful other than for debugging.

Replace it with a thread as I've done in TMQTTServer.

Apologies for my possible ignorance...

After having a quick look at the code... I see many threads being created, Lists and Queues but no CriticalSections/Locking.

Are there components Thread Safe?

Presently all it does is trigger an event

function TMQTTServer.ValidateClientID(AClientID: UTF8String): Boolean;
begin
  Result := True;
  if Assigned(FOnValidateClientID) then
    FOnValidateClientID(Self,AClientID,Result);
end;                            

The MQTT components should not depend on my utility and crypto packages. This will require removing the use of TPasswordManager by TMQTTServer. Future versions of this package should trigger an event to validate usernames and passwords.

Rewrite the code to use TMemoryStream rather than TBuffer. This will eliminate dependency on my bkUtils package.

Currently they persist indefinitely.

Retained messages currently stored in RAM and managed by TMQTTServer and are lost whenever the server process restarts. Ideally, retained messages should be stored in a file so that they can persist between server instantiations.

A similar mechanism exists in Mosquitto server.

It would be fantastic if this was made to work with Delphi since it is the only MQTT solution that seems to handle the full MQTT 3.1.1 spec as well as SSL/TLS.

Will a Delphi (10.2) version be available in a near future?

Hi,
I try to get client and serverapp running on a raspberry pi (3B+ with raspbian lite (no desktop)) with free pascal only, not lazarus.
Is there an example code to achieve it.
Thanks,
Rudi

The demo applications should support TLS/SSL.

On the subscriptions tab there should be a checkbox column titled "persistent" that updates the persistent property of a subscription. A subscription marked persistent should be saved to a server configuration file.

There is a mechanism to load/save persistent subscriptions to a stream but it is not being used. See TMQTTSubscriptionList.LoadFromStream/SaveToStream

It would probably be better to load/save this as an inifile or in some other text format.

The command line options and command line help needs to be updated with a way to specify a persistent subscriptions file.

The startup process needs to be modified to load a persistent subscriptions file at startup.