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Custom login module

Hello to all,

I'm trying to develop a custom login modul. Now I did as described at

But authentication always fails.

How can I read the provided user? Is it "user_name" or "j_user" as in the http-post?

Is it possible to debug the module? It is deployed as library and I don't know how to debug it.

Please advice

Regards Christian

Next my code:

package de.xy.ume;import java.util.Map;import;import;import;import;import;import;import;import;import;import;import;public class FilterUsername extends AbstractLoginModule {    // Define the variables that will be used later on:    private CallbackHandler callbackHandler = null;    private Subject subject = null;    private Map sharedState = null;    private Map options = null;    // This is the name of the user you have created on     // the J2EE Engine so you can test the login module    private String userName = null;    private boolean successful;    private boolean nameSet;    /**     * The method initializes the login module with the      * relevant authentication and state information.     */    public void initialize(        Subject subject,        CallbackHandler callbackHandler,        Map sharedState,        Map options) {        // This is the only required step for the method        super.initialize(subject, callbackHandler, sharedState, options);        // Initializing the values of the variables        this.callbackHandler = callbackHandler;        this.subject = subject;        this.sharedState = sharedState;        this.options = options;        this.successful = false;        this.nameSet = false;    }    /**     * Retrieves the user credentials and checks them. This is      * the first part of the authentication process.     */    public boolean login() throws LoginException {        // Retrieve the user credentials via the callback        // handler.        // In this case we get the user name from the HTTP         // request parameters.        Callback[] callbacks = new Callback[1];        callbacks[0] = new HttpGetterCallback();        /* The type and the name specify which part of the HTTP request             * should be retrieved. For Web container authentication, the             * supported types are defined in the interface            *            * For programmatical authentication with custom callback             * handler the supported types depend on the used callback handler.            */        ((HttpGetterCallback) callbacks[0]).setType(            HttpCallback.REQUEST_PARAMETER);        //((HttpGetterCallback) callbacks[0]).setName("user_name");             ((HttpGetterCallback) callbacks[0]).setName("j_user");        try {            callbackHandler.handle(callbacks);        } catch (UnsupportedCallbackException e) {            return false;        } catch (IOException e) {            throwUserLoginException(e, LoginExceptionDetails.IO_EXCEPTION);        }        //Returns an array of all request parameters with name "user_name".        String[] requestParameters =            (String[]) ((HttpGetterCallback) callbacks[0]).getValue();        if ((requestParameters != null) && requestParameters.length > 0) {            userName = requestParameters[0];        }        if (userName == null) {            throwNewLoginException("No user name provided.");        }                                /* When you know the user name, update the user information                 * using data from the persistence. The operation must                 * be done before the user credentials checks. This method also                 * checks the user name so that if a user with that name does not                 * exist in the active user store, a                 * java.lang.SecurityException is thrown.                */            try {                refreshUserInfo(userName);            } catch (SecurityException e) {                throwUserLoginException(e);            }            /* Checks if the given user name starts with the specified                 * prefix in the login module options. If no prefix is specified,                 * then all users are trusted.                */            /*                            String prefix = (String) options.get("user_name_prefix");            if ((prefix != null) && !userName.startsWith(prefix)) {                throwNewLoginException("The user is not trusted.");            }            */            /* This is done if the authentication of the login module is                     * successful.                * Only one and exactly one login module from the stack must put                 * the user name in the shared state. This user name represents                 * the authenticated user.                 * For example if the login attempt is successful, method                 * getRemoteUser() of                 * the HTTP request will retrieve exactly this name.                 */            if (sharedState.get(AbstractLoginModule.NAME) == null) {                sharedState.put(AbstractLoginModule.NAME, userName);                nameSet = true;            }                                successful = true;            return true;            }    /**        * Commit the login. This is the second part of the authentication         * process.        * If a user name has been stored by the login() method,         * the user name is added to the subject as a new principal.        */    public boolean commit() throws LoginException {        if (successful) {            /* The principals that are added to the subject should              * implement can use the class              * for this purpose.              */            Principal principal = new Principal(userName);            subject.getPrincipals().add(principal);            /* If the login is successful, then the principal corresponding              * to the <userName> (the same user name that has been added              * to shared state) must be added in the shared state too.              * This principal is considered to be the main principal              * representing the user.             * For example, this principal will be retrieved from method              * getUserPrincipal() of the HTTP request.              */            if (nameSet) {                sharedState.put(AbstractLoginModule.PRINCIPAL, principal);            }        } else {            userName = null;        }        return true;    }    /**     * Abort the authentication process.     */    public boolean abort() throws LoginException {        if (successful) {            userName = null;            successful = false;        }        return true;    }    /**     * Log out the user. Also removes the principals and      * destroys or removes the credentials that were associated       * with the user during the commit phase.     */    public boolean logout() throws LoginException {        // Remove principals and credentials from subject         if (successful) {            subject.getPrincipals(Principal.class).clear();            successful = false;        }        return true;    }}
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3 Answers

  • Best Answer
    Posted on Mar 27, 2012 at 12:01 PM


    I solved the problem.

    First you have to read the username with parameter "j_user".

    After redeploying the library you have to remove the module once from the login modules stack.

    After removing you can add it again. So the new (last deployed) code will be used.

    Regards Christian

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  • Posted on Mar 26, 2012 at 04:03 PM

    Hello Christian,

    You have to use NameCallback to read user name and PasswordCallback to read password in custom login module.

    Attached is the BasicPasswordLoginModule code of NW 7.3 version. I used same code that is provided in standard and could able to read user name and password in my custom login module.

    For NW 7.0 version you need to decompile the code.



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  • author's profile photo Former Member
    Former Member
    Posted on Dec 08, 2014 at 08:38 AM


    I am facing the similar problem in Custom Login Module. I am trying to achieve Single Sign On for our Application. I am using NWDS 7.0.

    The statement,

    String[] requestParameters = (String[]) ((HttpGetterCallback) callbacks[0]).getValue();

    is returning null. Used debuggers to get the value of requestParameters.

    The callback is happening correctly. But not getting the value against name 'user_name' which I am trying to fetch from the url of our Application.

    As suggested by Christian, I removed the Login module from Login Module Stack and added it again.

    But It didn't work.

    Kindly suggest a solution to resolve the issue.

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