[[http-clients]]
=== HTTP/REST clients and security

The {es} {security-features} work with standard HTTP
https://en.wikipedia.org/wiki/Basic_access_authentication[basic authentication]
headers to authenticate users. Since Elasticsearch is stateless, this header must
be sent with every request:

[source,shell]
--------------------------------------------------
Authorization: Basic <TOKEN> <1>
--------------------------------------------------
<1> The `<TOKEN>` is computed as `base64(USERNAME:PASSWORD)`

Alternatively, you can use
<<token-authentication-services,token-based authentication services>>.

[discrete]
[[http-clients-examples]]
==== Client examples

This example uses `curl` without basic auth to create an index:

[source,shell]
-------------------------------------------------------------------------------
curl -XPUT 'localhost:9200/idx'
-------------------------------------------------------------------------------

[source,js]
-------------------------------------------------------------------------------
{
  "error":  "AuthenticationException[Missing authentication token]",
  "status": 401
}
-------------------------------------------------------------------------------

Since no user is associated with the request above, an authentication error is
returned. Now we'll use `curl` with basic auth to create an index as the
`rdeniro` user:

[source,shell]
---------------------------------------------------------
curl --user rdeniro:taxidriver -XPUT 'localhost:9200/idx'
---------------------------------------------------------

[source,js]
---------------------------------------------------------
{
  "acknowledged": true
}
---------------------------------------------------------

[discrete]
[[http-clients-secondary-authorization]]
==== Secondary authorization

Some APIs support secondary authorization headers for situations where you want
tasks to run with a different set of credentials. For example, you can send the
following header in addition to the basic authentication header:

[source,shell]
--------------------------------------------------
es-secondary-authorization: Basic <TOKEN> <1>
--------------------------------------------------
<1> The `<TOKEN>` is computed as `base64(USERNAME:PASSWORD)`

The `es-secondary-authorization` header has the same syntax as the
`Authorization` header. It therefore also supports the use of
<<token-authentication-services,token-based authentication services>>. For
example:

[source,shell]
--------------------------------------------------
es-secondary-authorization: ApiKey <TOKEN> <1>
--------------------------------------------------
<1> The `<TOKEN>` is computed as `base64(API key ID:API key)`


[discrete]
[[http-clients-libraries]]
==== Client libraries over HTTP

For more information about using {security-features} with the language
specific clients, refer to:

* {java-rest}/_basic_authentication.html[Java]
* {jsclient-current}/auth-reference.html[JavaScript]
* https://www.elastic.co/guide/en/elasticsearch/client/net-api/master/configuration-options.html[.NET]
* https://metacpan.org/pod/Search::Elasticsearch::Cxn::HTTPTiny#CONFIGURATION[Perl]
* https://www.elastic.co/guide/en/elasticsearch/client/php-api/master/security.html[PHP]
* https://elasticsearch-py.readthedocs.io/en/master/#ssl-and-authentication[Python]
* https://github.com/elasticsearch/elasticsearch-ruby/tree/master/elasticsearch-transport#authentication[Ruby]