Basic authentication setup for Elasticsearch Java REST 5 client

To use basic authentication in the REST 5 client, set a default authorization header:

var creds = Base64.getEncoder()
    .encodeToString("user:test-user-password".getBytes());

Rest5ClientBuilder restClient = Rest5Client
    .builder(new HttpHost("https", "localhost", 9200))
    .setDefaultHeaders(new Header[]{
        new BasicHeader("Authorization", "Basic " + creds)
    });
		

To configure authentication behavior, pass an HttpClientConfigCallback when building the Rest5Client. The callback's single method takes an instance of org.apache.hc.client5.http.impl.async.HttpAsyncClientBuilder as an argument and returns the same type, so you can modify the provided builder and return it for the client to use.

By default, the HTTP client uses preemptive authentication: it includes credentials in the initial request. You might want to use non-preemptive authentication, which sends a request without credentials and retries with the header after a 401 Unauthorized challenge. To do this, set an HttpClientConfigCallback with auth caching disabled:

HttpHost host = new HttpHost("http", "localhost", 9200);

var creds = Base64.getEncoder().encodeToString("user:test-user-password".getBytes());

Rest5ClientBuilder restClient = Rest5Client
    .builder(new HttpHost("https", "localhost", 9200))
    .setHttpClientConfigCallback(HttpAsyncClientBuilder::disableAuthCaching)
    .setDefaultHeaders(new Header[]{
        new BasicHeader("Authorization", "Basic " + creds)
    });
		

1. Disables preemptive authentication

For more options, refer to Other authentication methods in the Elasticsearch Java REST 5 client.