This adds HTTP pipelining support to netty. Previously pipelining was not
supported due to the asynchronous nature of elasticsearch. The first request
that was returned by Elasticsearch, was returned as first response,
regardless of the correct order.
The solution to this problem is to add a handler to the netty pipeline
that maintains an ordered list and thus orders the responses before
returning them to the client. This means, we will always have some state
on the server side and also requires some memory in order to keep the
responses there.
Pipelining is enabled by default, but can be configured by setting the
http.pipelining property to true|false. In addition the maximum size of
the event queue can be configured.
The initial netty handler is copied from this repo
https://github.com/typesafehub/netty-http-pipeliningCloses#2665
This adds support to return the "Access-Control-Allow-Credentials" header
if needed, so CORS will work flawlessly with authenticated applications.
Closes#6380
This commit adds regular expression support for the allow-origin
header depending on the value of the request `Origin` header.
The existing HttpRequestBuilder is also extended to support the
OPTIONS HTTP method.
Relates #5601Closes#6891