Authentication

This section describes the framework provided by Sling to authenticate HTTP requests.

Let's look at generic request processing of Sling: Sling is linked into the outside world by registering the Sling Main Servlet – implemented by the SlingMainServlet class in the Sling Engine bundle – with an OSGi HttpService. This registration is accompanyied with an implementation instance of the OSGi HttpContext interface, which defines a method to authenticate requests: handleSecurity.

This method is called by the OSGi HTTP Service implementation after the servlet has been selected to handle the request but before actually calling the servlet's service method.

The important thing to note here is, that at the time the handleSecurity method is called, the SlingMainServlet is not yet in control of the request. So any functionality added by the SlingMainServlet, notably the SlingHttpServletRequest and SlingHttpServletResponse objects are not available to the implementation of the handleSecurity method.

The following pages describe the full details of request authentication in Sling in full detail:

• Tasks: Authentication of HTTP Requests is generally a two-step process: First the credentials must be extracted from the request and second the credentials must be validated. In the case of Sling this means acquiring a JCR Session.
• Actors: The authentication process involves a number of actors contributing to the concepts, the API and the particular implementations.
• Framework: The core piece of functionality with respect to authentication in Sling is contained in the Sling Commons Auth bundle. This bundle provides the API for Sling and Sling applications to make use of authentication.
• AuthenticationHandler: The AuthenticationHandler interface defines the service API which may be implemented by authentication handlers registered as OSGi services.