Servlet authentication filters

A machine readable storage medium having instructions stored thereon that when executed by a processor cause a system to:

• receive at a servlet the request to access the resource;
• modify at least one of the request, a state of the request and information accompanying the request by invoking one or more authentication filters to the request to form a modified request, wherein at least one authentication filter of the one or more authentication filters contacts an authentication provider, wherein the invocation of the one or more authentication filters causes an authentication state of a source of the request to be modified such that said source is changed from an unauthenticated status to an authenticated status as a result of the invocation of the one or more authentication filters;
• determine whether the modified request still requires additional authentication;
• permit the modified request to be processed if the modified request does not require additional authentication;
• apply at least one authentication process to the modified request if the modified request still requires additional authentication;
• and
• provide access to a protected resource in response to receiving authentication information.

A method for authenticating requests to access resources in an application server environment, said method comprising:

• extending a default authentication process of a servlet container by providing a set of external authentication filters to the default authentication process, wherein said external authentication filters are supplemental to the default authentication process of the servlet container;
• receiving a request to access a resource;
• invoking the default authentication process of the servlet container;
• determining whether the request has been authenticated;
• if the request has not been authenticated, invoking a chain of said external authentication filters, wherein each of said external authentication filters uses the chain in order to access a next external authentication filter in the set, and wherein execution of the chain of said external authentication filters causes a state of the request to be modified, such that as a result of the state being modified, the request can be authenticated by the servlet container;
• and
• providing access to the resource by the servlet container if the request has been authenticated.