Re: [mosquitto-dev] mosquitto_sub with binary payload

[Roger Light <roger@xxxxxxxxxx>]

Hi Steve,

This is now fixed in the `fixes` branch, which will become part of
2.0.12. Thanks for the report!

https://github.com/eclipse/mosquitto/commit/6028d0e33e0ca2a215caa556633e3418e45b094b

Regards,

Roger

On Wed, 9 Jun 2021 at 18:13, Steve Mullock <sjmeclipse@xxxxxxxxxx> wrote:
>
> Thanks for the replies
>
> Greg Troxel
> -----------
>
> You are clearly correct. After some more research it seems that on Windows stdout is always
> opened in text mode by the OS. fwrite() therefore prepends /r to /n
>
> It is possible to change it using a MS specific call _setmode(_fileno(stdout), O_BINARY) which
> would have to be inserted between some #ifdef WIN32 #endif lines
>
> Given the documentation, it would seem reasonable to expect this to be done when specifying
>
> -F %p
>
> which is supposed to give binary, control characters and all.
>
> I just don't have the confidence to have a bash at fixing it. I'd have to be certain I
> understood which bit goes where and compile from source on Windows.
>
> Kees Nuyt
> ---------
> Good point about ctrl Z. Actually, it does not seem to cause the pipe to stop, but it was
> definitely worth checking.
>
>
>
> There are certainly work-arounds. The easiest would be to write my own simple subscribing
> client. However, I am trying to convince collaborators to have a go at looking at my MQTT
> output and I am trying to keep it as simple as possible for them, because, frankly, they are a
> bit feeble. It would be nice to be able to say "Look just use this free utility and then
> examine the file". If they want to start with encryption and security, they can, without me
> immediately having to do a load more work. The decoupling of publisher and subscriber is one
> of the things I like about MQTT.
>
> I am actually mostly sending text, although sometimes in Chinese! The problem is that I need
> to send a multiline message. I am uncomfortable with the payload changing according to which
> subscribing client is used. I started out publishing /r /n, because I knew they are Windows
> based. When I tested with mosquitto_sub I ended up with every line /r /r /n.
>
> Anyway, I think you guys have answered my question, so thanks.
>
> --
> Steve Mullock
>
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