Data serialization for embedded platforms: ASN.1, JSON, Protocol Buffers....

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It's a long time I work with embedded platforms, however I never used a  
well-defined and "standard" data serialization format. I often had the  
need to exchange data between platforms (Wifi, Ethernet, RS485...) and I  
always find a custom solution.

I perfectly understood the problem with this approach. Keeping the two  
(or more) side synchronized is very difficult and error-prone. When the  
sides are designed and maintaned by a single person/company, this  
approach could be sufficient. However I started to interface with other  
people, companies, very difficult techologies.

For example, I'm working on a IoT device that connects with AWS through  
MQTT protocol. I have to decide the data format of MQTT packets. They  
will be processed by AWS services, so JSON seems the perfect choice  
(maybe someone remember an old post where I was asking how to use a JSON  
in C for embedded platforms).
However JSON, considering it's a schema-less data format, is very  
complex to manage in C without using dynamic memory. So I'm thinking to  
use another data format, fithing with guys that will work with AWS,  
Javascript, Typescript, and so on (they doesn't understand why JSON  
isn't good on my side).

ASN.1 (mainly in uPER mode) and protobuf could be a good choice. However  
the backend/frontend guys don't know ASN.1, some has heard about protobuf.
I could insist to use ASN.1, however I'm not sure it is a good choice.  
And I don't know if they will be able to decode uPER messages in  
Typescript (for example). It seems they found something for BER, nothing  
for PER.

So this post just to discuss and share some experience on this topic.

Re: Data serialization for embedded platforms: ASN.1, JSON, Protocol Buffers....
pozz schreef:
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Or perhaps you're working with unreliable and/or incompetent people?  :P

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If you think it's "very complex" then perhaps you're taking a suboptimal  
approach.  Even in a schema-less data format you can agree on how to lay  
out the necessary information.  If you have an event-based JSON parser  
then it should be pretty easy (even with static allocation).

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