Warning: 299 Elasticsearch-5.6.3-1a2f265 "Content type detection for rest requests is deprecated. Specify the content type using the [Content-Type] header."

[jsiembida]

Please use the following questions as a guideline to help me answer
your issue/question without further inquiry. Thank you.

Which version of Elastic are you using?

[ ] elastic.v2 (for Elasticsearch 1.x)
[ ] elastic.v3 (for Elasticsearch 2.x)
[x] elastic.v5 (for Elasticsearch 5.x)
[ ] elastic.v6 (for Elasticsearch 6.x)

Please describe the expected behavior

HTTP reply without the titular warning (seems similar to #511)

Please describe the actual behavior

HTTP reply with the warning

Any steps to reproduce the behavior?

Send /_bulk index with Content-Type: application/x-ndjson; charset=UTF-8 instead of Content-Type: application/x-ndjson (seems the charset=UTF-8 triggers the warning).

Example call:

POST /_bulk HTTP/1.1
Host: metrics
Accept-Encoding: identity
Content-Length: 2213
Content-Type: application/x-ndjson; charset=UTF-8

Reply:

HTTP/1.1 200 OK
Warning: 299 Elasticsearch-5.6.3-1a2f265 "Content type detection for rest requests is deprecated. Specify the content type using the [Content-Type] header." "Thu, 09 Nov 2017 12:27:08 GMT"
content-type: application/json; charset=UTF-8
content-length: 1492

Again, removing the charset=UTF-8 makes the warning go:

POST /_bulk HTTP/1.1
Host: metrics
Accept-Encoding: identity
Content-Length: 2213
Content-Type: application/x-ndjson

And the clean reply now:

HTTP/1.1 200 OK
content-type: application/json; charset=UTF-8
content-length: 1492

Not sure that is expected, especially that ES itself uses charset=UTF-8 in replies.

[olivere]

Oh, okay. I'll have a look into this for the next release.

[olivere]

@jsiembida I don't see how/where Elastic will send Content-Type: application/x-ndjson; charset=UTF-8 anywhere? It will only send Content-Type: application/x-ndjson.

Can you explain how you triggered this?

[olivere]

That's also what ES specifies here.

[olivere]

@jsiembida Friendly ping.

[jsiembida]

Hi, thanks for feedback. I think you are absolutely right, this seems more like an ES issue.