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Comment by pagnol | Hacker News Reader

I didn't know CBOR, but it looks similar to BSON and MessagePack, or is there a significant difference?

Roughly that it isn't shit.

I say that a bit tongue in cheek, but really: BSON has a monstrous amount of basic data types, some of which make very little sense and are very difficult to round-trip through other formats; and MessagePack had crippling basic sanity issues with what-are-bytes-vs-strings in its early history and that's something you simply can't recover from without declaring game over and making a new spec.

CBOR has neither of these issues. It's almost completely isomorphic to json, plus supports byte arrays. It's very nice.

In the feature category, I'd also mention direct support for unbounded collections. CBOR can be its own container format for streaming data.

Does CBOR support lazy/partial deserialization? It's not a make-or-break feature, but the ability to pluck out individual fields from large MessagePack documents without deserializing the whole thing has been a significant performance/memory savings for me many times.

I haven't played with flatbuffers, but it probably supports this as well, given its design. Are there other binary protocols that have first-class (i.e. present with a good API in the client libraries for all major languages) support for lazy/partial deserialization?

CBOR is very similar to MsgPack, so yes (if you design the schema well enough).

Is/Can CBOR be canonicalized (like ASN.1, for example) for the purpose of unambiguous generation and interpretation of hashes?

EDIT: I am happy to see that it handles date-time. Not really my favorite part of the non-spec of JSON on that front...

You might be interested in IPLD in particular: https://ipld.io/

They use CBOR as the underlying serialization, and have a deep interest in canonicalization and applications of hashing.

More cbor ranting... In Python you can replace json.loads/dumps with cbor.loads/dumps with no further changes. Going back again may prove to be an issue when you discover just how much it is that json can't do.

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