Re: [hono-dev] Property bag at the end of topics for MQTT adapter?

["Pellmann Marc (INST/ECS4)" <Marc.Pellmann@xxxxxxxxxxxx>]

Hi

> > to be able to support setting of specific content types (and other properties
> > in the future) over the MQTT adapter I suggest to support properties in URL
> > format at the end of the topics. Microsoft uses the same on Azure - https://doc
> > s.microsoft.com/en-us/azure/iot-hub/iot-hub-mqtt-support.
> >
> > Topic would be something like
> >
> > telemetry/DEFAULT_TENANT/4711/?$content-
> > type=application%2Fjson%3B%20charset%3Dutf-8
> 
> Is it necessary to URL encode the properties? IMHO the topic name in MQTT is UTF-
> 8 encoded and should therefore not require encoding, or does it?

At least we need to encode the slash and also the question mark, so it will be much more easy to use URL encoding in general, I think.

Without encoding in the topic-structure would look like:

telemetry/DEFAULT_TENANT/4711/?$content-type=application/json; charset=utf-8

So you can not differentiate between a topic part and part from the value of the content-type. Also in other properties in the future there might be question marks etc.

Mit freundlichen Grüßen / Best regards
Marc Pellmann

Bosch Software Innovations GmbH
Core Products Development (INST/ECS4)
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