How to use X509 certificate with the Nest Elastic

I am currently upgrading from Elastic Search 1.7 to 5.2. I know there is no upgrade path, which is fine. One problem we had originally is with Nest and ElastiSearch.Net there was no way to attach an X509 certificate as it only had the ability to use Basic Authentication. To get around that we made copies of the existing github repos and modified the code directly to allow it. This ultimately is what kept us from upgrading for so long since we couldn't just use the nuget packages, because we now had custom code.

Now that we are upgrading I'm trying to find out if this was ever remedied. Or, at the very least are there any hooks that we can use to get the ElasticClient(in Nest) or the ElasticLowLevelClient (in ElasticSearch.Net) to take in a certificate and pass it on when making the call.

Another option, is to use a PUT request to create the Index on initial creation, which is where we are needing the certificate. The issue we have there is we require the use of the AutoMap method since we have some custom attributes added on our models, and need those to go in on Index creation. I'm not sure if there is a way to generate that result of AutoMap for a given model to JSON, and just use a webclient to attach the certificate.

Let me know if you need anymore details.

It's possible to customise the connections that both NEST and Elasticsearch.Net use all the way back to 1.x. This is done by providing your own implementation of IConnection to the ConnectionSettings instance that is passed to the ElasticClient constructor.

First create your custom IConnection; it's easiest to derive from HttpConnection

public class HttpConnectionWithClientCertificate : HttpConnection
{
    protected override HttpWebRequest CreateHttpWebRequest(RequestData requestData)
    {
        var request = base.CreateHttpWebRequest(requestData);
        // add the certificate to the request
        request.ClientCertificates.Add(new X509Certificate("path_to_cert"));
        return request;
    }
}

then pass this to ConnectionSettings

var node = new Uri("http://localhost:9200");
var connectionPool = new SingleNodeConnectionPool(node);
var connection = new HttpConnectionWithClientCertificate();
var settings = new ConnectionSettings(connectionPool, connection);
var client = new ElasticClient(config);