An extension of DefaultCookieAuthenticator that handles details like clearing old cookies and providing a default user name in some contexts

CustomCookieAuthenticator.java

/**
 * Custom cookie authentication
 */
public class CustomCookieAuthenticator extends DefaultCookieAuthenticator {

    private static final String LOGIN_FORM_PATH = "/auth/loginForm";
    private static final String LOGIN_PATH = "login";
    private static final String LOGOUT_PATH = "logout";


    private final UserDirectory userDirectory;


    @Inject CustomCookieAuthenticator(UserDirectory userDirectory) {
        this(userDirectory, false);
    }


    CustomCookieAuthenticator(UserDirectory userDirectory, boolean optional) {
        super(null, optional, AuthUtil.getRealm(), AuthUtil.getEncryptSecretKey());
        this.userDirectory = userDirectory;
    }

    @Inject void initialize() {
        setEncryptAlgorithm(AuthUtil.getEncryptAlgorithm());
        setCookieName(AuthUtil.getCookieName());
        setLoginFormPath(LOGIN_FORM_PATH);
        setLoginPath(LOGIN_PATH);
        setLogoutPath(LOGOUT_PATH);

        setVerifier(new SecretVerifier() {
            @Override public String getIdentifier(Request request, Response response) {
                String identifier = super.getIdentifier(request, response);
                return userDirectory.normalize(identifier);
            }

            @Override public int verify(String identifier, char[] secret) {
                boolean valid = userDirectory.verifyUser(identifier, secret);
                return valid ? RESULT_VALID : RESULT_INVALID;
            }

            @Override protected User createUser(
                    String identifier, Request request, Response response) {
                User user = super.createUser(identifier, request, response);
                Iterables.addAll(
                    request.getClientInfo().getPrincipals(),
                    userDirectory.getPrincipals(identifier, request.getAttributes()));
                return user;
            }
        });

        setEnroler(new Enroler() {
            @Override public void enrole(ClientInfo clientInfo) {
                clientInfo.setRoles(
                    userDirectory.getRoles(
                        clientInfo.getUser().getIdentifier(),
                        clientInfo.getPrincipals()
                    )
                    .transform(AuthRole::role)
                    .toList()
                );
            }
        });
    }


    @Override protected void login(Request request, Response response) {
        // Clear the credentials cookie so later processing doesn't replace
        // the form values with the old credentials.
        request.getCookies().removeFirst(getCookieName());

        super.login(request, response);
    }


    @Override protected CookieSetting getCredentialsCookie(Request request, Response response) {
        CookieSetting credentialsCookie = super.getCredentialsCookie(request, response);
        String path = AuthUtil.getCookieScope();
        String domain = AuthUtil.getCookieDomain(request);
        if (domain == null) {
            credentialsCookie.setPath(path);
            return credentialsCookie;
        } else {
            CookieSetting newCookie = new CookieSetting(
                credentialsCookie.getVersion(),
                credentialsCookie.getName(),
                credentialsCookie.getValue(),
                path,
                domain
            );
            response.getCookieSettings().removeFirst(credentialsCookie.getName());
            response.getCookieSettings().add(newCookie);
            return newCookie;
        }
    }

    @Override public void challenge(Response response, boolean stale) {
        super.challenge(response, stale);

        Optional<String> user = userDirectory.defaultUserFromRef(
            response.getRequest().getResourceRef());
        if (user.isPresent()) {
            response.getLocationRef().addQueryParameter(
                LoginFormServerResource.INITIAL_USER_VALUE,
                user.get()
            );
        }
    }
}