mqtt_as over websockets

[Tico06]

Hi There,
I'd like to know if it's possible to use mqtt_as over websockets ? I yes, does a howto exists somewhere ?

If no, would it be possible to implement in mqtt_as ? I can give it a try.

Thanks and regards,

Eric.

[peterhinch]

The mqtt_as library assumes a WiFi connection and uses nonblocking sockets. There is a need for an asynchronous MQTT client designed for other connection types. I wrote this short doc outlining a future MQTT client which would be agnostic of physical connection.

I don't think hacking mqtt_as is the way forward. WiFi wrangling is too deeply baked into the design.

[Tico06]

thx Peter.

I am not sure I catch your point.

My idea was to, thanks to parameters, offer the users the possibility to use a aiohttp.ClientSession.ws_connect(self, url, ssl=None) in place of socket.socket.connect(). For me it's a rewrite of ‎MQTT_base._connect(self, clean), offering the two options.

I don't see here any point about blocking or nonblocking sockets. But maybe I see it simpler than it is...

[peterhinch]

The point about nonblocking sockets is that you need a means of enabling concurrency. The library runs a number of concurrent tasks, and the application is likely to run others. I'm not familiar with websockets - I don't know if they have a nonblocking mode - but any solution will need to support concurrency.

Support for other types of connection has been extensively discussed, but for various reasons has not been implemented. However feel free to experiment.

[Tico06]

Yes I will. I think it's an interesting option.

Reg

[jomasnash]

Hi There, I'd like to know if it's possible to use mqtt_as over websockets ? I yes, does a howto exists somewhere ?

If no, would it be possible to implement in mqtt_as ? I can give it a try.

Thanks and regards,

Eric.

Yes, this is possible. I have implemented a client that does this. But I only have implemented the things I needed so it is not a ready to use product.

Also concurrency is not a problem.

Websocket has the advantage that packets arrive complete** in a websocket data packet, so there is no need to get every single byte and then decide what to do. (**according to the MQTT spec's it is possible that packets are split but I doubt if this ever happens).

Also Websockets don't have the handshaking that normal http traffic has. Only in the beginning the handshaking is done, after that, you have a bidirectional link to work with.

If you start using websockets you can use aiohttp from micropython-lib/python-ecosys. Be sure to use the latest version because it had a bug that I also fixed, see this issue micropython/micropython-lib#941
In this issue there also is an example how to connect to a server over websockets.

Keep in mind that aiohttp also uses getaddrinfo that is blocking. I have also made a async version of getaddrinfo but it is written in python.

[Tico06]

Thx Jomas, I'll investigate in that direction. Le dim. 8 juin 2025, 20:50, jomasnash ***@***.***> a écrit :

…

Hi There, I'd like to know if it's possible to use mqtt_as over websockets ? I yes, does a howto exists somewhere ? If no, would it be possible to implement in mqtt_as ? I can give it a try. Thanks and regards, Eric. Yes, this is possible. I have implemented a client that does this. But I only have implemented the things I needed so it is not a ready to use product. Also concurrency is not a problem. Websocket has the advantage that packets arrive complete** in a websocket data packet, so there is no need to get every single byte and then decide what to do. (**according to the MQTT spec's it *is* possible that packages are split but I doubt if this ever happens). Also Websockets don't have the handshaking that normal http traffic has. Only in the beginning the handshaking is done, after that, you have a bidirectional link to work with. If you start using websockets you can use aiohttp from micropython-lib/python-ecosys. Be sure to use the latest version because it had a bug that I also fixed, see this issue micropython/micropython-lib#941 <micropython/micropython-lib#941> In this issue there also is an example how to connect to a server over websockets. Keep in mind that aiohttp also uses getaddrinfo that is blocking. I have also made a async version of getaddrinfo but it is written in python. — Reply to this email directly, view it on GitHub <#17431 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEHMCZ6AWXVNGDZ2DGWTJCL3CSAXFAVCNFSM6AAAAAB6STSBHSVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTGNBQGM3TIMQ> . You are receiving this because you authored the thread.Message ID: ***@***.*** com>