"ipfs dag get" does not have CBOR output; hence data roundtrip is not guaranteed as JSON mangles data stored by application

[AndreaCensi]

Version information:

go-ipfs version: 0.4.17-
Repo version: 7
System version: amd64/darwin
Golang version: go1.10.3

Type:

enhancement / bug

Description:

It seems that at this time there is no way to retrieve a dag in CBOR format.

Source: https://gowalker.org/github.com/ipfs/go-ipfs/core/commands/dag

dag put allows the input to be CBOR

dag get does not have the option to have the output in CBOR.

This feature is important because, as previously concluded elsewhere (ipld/ipld#65), JSON is not a robust format for data transfer, so applications that want to preserve data integrity should use CBOR.

This counts as a bug if we want it to be true that "an application can put a CBOR file, get a hash, and retrieve exactly the same file with that hash".

[Stebalien]

Unfortunately, this is an annoying limitation of the dag API because it tries to convert formats. Personally, I recommend using the ipfs block API for this reason.

[Stebalien]

(closing as a duplicate of #4313)