ElasticSearch Access-Control-Allow-Headers header is not present

Question

I am making a POST request from a local https server to an ElasticSearch endpoint which has been configured as follows

http.cors.enabled: true
http.cors.allow-credentials: true
http.cors.allow-origin: "*"
http.cors.allow-methods: OPTIONS, HEAD, GET, POST, PUT, DELETE
http.cors.allow-headers: X-Requested-With, X-Auth-Token, Content-Type, Content-Length, Authorization, Access-Control-Allow-Headers, Accept

The request has headers:

Access-Control-Allow-Headers: Accept, Access-Control-Allow-Headers, Authorization, Content-Type
Content-Type: application/json; charset=utf-8
Accept: application/json; charset=utf-8
Access-Control-Allow-Credentials: true
Authorization: (basic authentication token)

On a POST request, the following error appears: Request header field Access-Control-Allow-Headers is not allowed by Access-Control-Allow-Headers in preflight response.

The network debugger indeed shows that the Access-Control-Allow-Headers header is not present in the response header. The response header:

HTTP/1.1 200 OK
Access-Control-Allow-Origin: https://dl.dropboxusercontent.com
Vary: Origin
Access-Control-Allow-Methods: 
Access-Control-Allow-Credentials: true
Access-Control-Max-Age: 1728000
content-length: 0
date: Fri, 29 Apr 2016 14:08:14 GMT

Note that Access-Control-Allow-Headers is not present and Access-Control-Allow-Methods is blank. All possible string formats have been tested, and these headers do not appear.

Answer 1

You should add following signs to your elasticsearch.yml:

http.cors.allow-methods : OPTIONS, HEAD, GET, POST, PUT, DELETE
http.cors.allow-headers : Authorization, X-Requested-With,X-Auth-Token,Content-Type, Content-Length

and then restart the es, enjoy!

Answer 2

I finally solved the problem with these config lines in elasticsearch.yml:

http.cors.enabled: true
http.cors.allow-origin: /https?:\/\/(localhost)?(127.0.0.1)?(:[0-9]+)?/
http.cors.allow-methods: OPTIONS, HEAD, GET, POST, PUT, DELETE
http.cors.allow-headers: Authorization, X-Requested-With,X-Auth-Token,Content-Type, Content-Length