How to call custom Login Module from JSP

Question

Hi,
I am stuck with the following issue:
1) Exactly as presented in help.sap.com (http://help.sap.com/saphelp_nw04/helpdata/en/3f/1be040e136742ae10000000a155106/content.htm) I created custom login module and deployed it as a library on J2EE server. When I configured it to be used for my applications in the Security provider but I am getting "No user name provided" exception everytime when my applications use this custom login module.
2) I realized that I would need to call my custom module somewhere within my application (simple JSP) using LoginContext class and then use MyLoginContext.login() spec to initiate login process. But I am not able to pass CallbackHandler parameters from JSP application to my custom login module.
So I have the following questions:
1. Can I pass parameters using LoginContext and CallbackHandler from JSP to my custom login module (created as exact copy of HELP.SAP.COM example) or this module cannot be used this way.
2. How to pass CallbackHandler correctly to my custom login module from JSP. When I am trying to use CallbackHandler, I am getting "Abstract Class cannot be called" error.
I'd appreciate any little help on this matter.
Thanks and regards,
Mike

Answer 1

You have two alternatives to do this:
You can declare your JSP as a protected resource with the use of the deployment descriptors of the application (web.xml) and add the custom login module in the authentication stack of the application. This way, you will use container-based authentication, i.e. the Web Container will enforce the authentication and it will call the custom login module before it dispatches to the JSP. I recommend you this approach because it requires less coding and it makes the whole thing a matter of configuration. The configuration can be later on enhanced or changed runtime without the need to re-build and re-deploy the application. If you choose this approach you can go to the documentation of the server for help on how to modify the login module stack of the application.
You can also use programmatic authentication by using JAAS API. To do this you need to create a custom security policy configuration with login module stack containing the custom login module, and then use the standard JAAS mechanism - new LoginContext(<configuration>, <callback-handler>).login(). This approach requires that you write your own callback handler and handle any LoginException.
Let us know which approach you prefer and whether you have difficulties implementing it!