return a json object from config show

[Stebalien]

This doesn't change there CLI output, it just means that the server responds with a JSON output by default.

Fixes #5335.

[Stebalien]

@diasdavid is this likely to break something?

[Stebalien]

So, this does cause a bit of an issue: Users using old clients against newer servers won't see nicely formatted json, they'll see dense json. However, I'm not too concerned about that. Clients with this patch applied still work correctly against older servers.

[whyrusleeping]

This seems fine to me, but I would double check with the javascripters before merging.

[Stebalien]

@hacdias or @alanshaw, thoughts?

[hacdias]

If the Content-Type header is now application/json instead of plain/text, the js-ipfs-api will still work as expected.

[Stebalien]

It is. These are the old headers:

< HTTP/1.1 200 OK
< Access-Control-Allow-Headers: X-Stream-Output, X-Chunked-Output, X-Content-Length
< Access-Control-Expose-Headers: X-Stream-Output, X-Chunked-Output, X-Content-Length
< Content-Type: text/plain
< Server: go-ipfs/0.4.18-dev
< Trailer: X-Stream-Error
< Vary: Origin
< X-Stream-Output: 1
< Date: Sat, 11 Aug 2018 16:44:20 GMT
< Transfer-Encoding: chunked

These are the new headers:

< HTTP/1.1 200 OK
< Access-Control-Allow-Headers: X-Stream-Output, X-Chunked-Output, X-Content-Length
< Access-Control-Expose-Headers: X-Stream-Output, X-Chunked-Output, X-Content-Length
< Content-Type: application/json
< Server: go-ipfs/0.4.18-dev
< Trailer: X-Stream-Error
< Vary: Origin
< Date: Sat, 11 Aug 2018 16:46:12 GMT
< Transfer-Encoding: chunked

Note that the X-Stream-Output header is also gone.

[hacdias]

Great @Stebalien ! 😄

[Kubuxu]

We should test it out against js-ipfs-api to be 100% sure. We should probably also test out go-ipfs-api and java-ipfs-api. This is touchy change as it changes a default behaviour.

[Stebalien]

@Kubuxu looks like this'll work just fine with js-ipfs-api as js-ipfs already behaves this way.

[Stebalien]

I'll take the comments from @hacdias and @whyrusleeping as "two signoffs".