private void processReturn(HttpServletRequest req, HttpServletResponse resp)
      throws ServletException, IOException {
    Account principal = this.verifyResponse(req);

    // System.out.println(principal);

    String returnURL = req.getParameter("exist_return");

    if (principal == null) {
      // this.getServletContext().getRequestDispatcher("/openid/login.xql").forward(req, resp);
      resp.sendRedirect(returnURL);
    } else {
      HttpSession session = req.getSession(true);

      // ((XQueryURLRewrite.RequestWrapper)req).setUserPrincipal(principal);

      Subject subject = new Subject();

      // TODO: hardcoded to jetty - rewrite
      // *******************************************************
      DefaultIdentityService _identityService = new DefaultIdentityService();
      UserIdentity user = _identityService.newUserIdentity(subject, principal, new String[0]);

      Authentication cached = new HttpSessionAuthentication(session, user);
      session.setAttribute(HttpSessionAuthentication.__J_AUTHENTICATED, cached);
      // *******************************************************

      resp.sendRedirect(returnURL);
    }
  }
 @Override
 protected void doPost(HttpServletRequest req, HttpServletResponse resp)
     throws ServletException, IOException {
   if ("true".equals(req.getParameter("is_return"))) {
     processReturn(req, resp);
   } else {
     String identifier = req.getParameter("openid_identifier");
     if (identifier != null) {
       this.authRequest(identifier, req, resp);
     } else {
       // this.getServletContext().getRequestDispatcher("/openid/login.xql").forward(req, resp);
       resp.sendRedirect(OpenIDRealm.instance.getSecurityManager().getAuthenticationEntryPoint());
     }
   }
 }
  // authentication response
  public Account verifyResponse(HttpServletRequest httpReq) throws ServletException {

    try {
      // extract the parameters from the authentication response
      // (which comes in as a HTTP request from the OpenID provider)
      ParameterList response = new ParameterList(httpReq.getParameterMap());

      // retrieve the previously stored discovery information
      DiscoveryInformation discovered =
          (DiscoveryInformation) httpReq.getSession().getAttribute("openid-disc");

      // extract the receiving URL from the HTTP request
      StringBuffer receivingURL = httpReq.getRequestURL();
      String queryString = httpReq.getQueryString();
      if (queryString != null && queryString.length() > 0)
        receivingURL.append("?").append(httpReq.getQueryString());

      // verify the response; ConsumerManager needs to be the same
      // (static) instance used to place the authentication request
      VerificationResult verification =
          manager.verify(receivingURL.toString(), response, discovered);

      // examine the verification result and extract the verified
      // identifier
      Identifier verified = verification.getVerifiedId();
      if (verified != null) {
        // success

        String accountName = AccountImpl.escape(verified.getIdentifier());
        AbstractAccount account = (AbstractAccount) OpenIDRealm.instance.getAccount(accountName);
        if (account == null) {
          Database db = OpenIDRealm.instance.getDatabase();
          org.exist.security.Subject currentSubject = db.getSubject();
          try {
            db.setSubject(db.getSecurityManager().getSystemSubject());

            // XXX: set OpenID group by default
            account =
                (AbstractAccount)
                    OpenIDRealm.instance.addAccount(
                        new UserAider(OpenIDRealm.instance.getId(), accountName));
          } finally {
            db.setSubject(currentSubject);
          }
        }

        org.exist.security.Subject principal = new SubjectAccreditedImpl(account, verified);

        AuthSuccess authSuccess = (AuthSuccess) verification.getAuthResponse();
        authSuccess.getExtensions();

        if (authSuccess.hasExtension(SRegMessage.OPENID_NS_SREG)) {
          MessageExtension ext = authSuccess.getExtension(SRegMessage.OPENID_NS_SREG);
          if (ext instanceof SRegResponse) {
            SRegResponse sregResp = (SRegResponse) ext;
            for (Iterator iter = sregResp.getAttributeNames().iterator(); iter.hasNext(); ) {
              String name = (String) iter.next();
              if (LOG.isDebugEnabled()) LOG.debug(name + " : " + sregResp.getParameterValue(name));
              principal.setMetadataValue(
                  AXSchemaType.valueOfNamespace(name), sregResp.getParameterValue(name));
            }
          }
        }
        if (authSuccess.hasExtension(AxMessage.OPENID_NS_AX)) {
          FetchResponse fetchResp =
              (FetchResponse) authSuccess.getExtension(AxMessage.OPENID_NS_AX);

          List aliases = fetchResp.getAttributeAliases();
          for (Iterator iter = aliases.iterator(); iter.hasNext(); ) {
            String alias = (String) iter.next();
            List values = fetchResp.getAttributeValues(alias);
            if (values.size() > 0) {
              if (LOG.isDebugEnabled()) LOG.debug(alias + " : " + values.get(0));
              principal.setMetadataValue(AXSchemaType.valueOfAlias(alias), (String) values.get(0));
            }
          }
        }
        // update metadata
        Database db = OpenIDRealm.instance.getDatabase();
        org.exist.security.Subject currentSubject = db.getSubject();
        try {
          db.setSubject(db.getSecurityManager().getSystemSubject());

          OpenIDRealm.instance.updateAccount(principal);
        } finally {
          db.setSubject(currentSubject);
        }

        OpenIDUtility.registerUser(principal);
        return principal;
      }
    } catch (OpenIDException e) {
      LOG.error(e);
    } catch (ConfigurationException e) {
      LOG.error(e);
    } catch (PermissionDeniedException e) {
      LOG.error(e);
    } catch (EXistException e) {
      LOG.error(e);
    }

    return null;
  }
  // authentication request
  public String authRequest(
      String userSuppliedString, HttpServletRequest httpReq, HttpServletResponse httpResp)
      throws IOException, ServletException {

    if (OpenIDRealm.instance == null) {
      ServletOutputStream out = httpResp.getOutputStream();
      httpResp.setContentType("text/html; charset=\"UTF-8\"");
      httpResp.addHeader("pragma", "no-cache");
      httpResp.addHeader("Cache-Control", "no-cache");

      httpResp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);

      out.print("<html><head>");
      out.print("<title>OpenIDServlet Error</title>");
      out.print("<link rel=\"stylesheet\" type=\"text/css\" href=\"error.css\"></link></head>");
      out.print("<body><div id=\"container\"><h1>Error found</h1>");

      out.print("<h2>Message:");
      out.print("OpenID realm wasn't initialized.");
      out.print("</h2>");

      // out.print(HTTPUtils.printStackTraceHTML(t));

      out.print("</div></body></html>");
      return null;
    }
    try {
      String returnAfterAuthentication = httpReq.getParameter("return_to");

      // configure the return_to URL where your application will receive
      // the authentication responses from the OpenID provider
      String returnToUrl =
          httpReq.getRequestURL().toString()
              + "?is_return=true&exist_return="
              + returnAfterAuthentication;

      // perform discovery on the user-supplied identifier
      List<?> discoveries = manager.discover(userSuppliedString);

      // attempt to associate with the OpenID provider
      // and retrieve one service endpoint for authentication
      DiscoveryInformation discovered = manager.associate(discoveries);

      // store the discovery information in the user's session
      httpReq.getSession().setAttribute("openid-disc", discovered);

      // obtain a AuthRequest message to be sent to the OpenID provider
      AuthRequest authReq = manager.authenticate(discovered, returnToUrl);

      if (authReq.getOPEndpoint().indexOf("myopenid.com") > 0) {
        SRegRequest sregReq = SRegRequest.createFetchRequest();

        sregReq.addAttribute(AXSchemaType.FULLNAME.name().toLowerCase(), true);
        sregReq.addAttribute(AXSchemaType.EMAIL.name().toLowerCase(), true);
        sregReq.addAttribute(AXSchemaType.COUNTRY.name().toLowerCase(), true);
        sregReq.addAttribute(AXSchemaType.LANGUAGE.name().toLowerCase(), true);

        authReq.addExtension(sregReq);
      } else {

        FetchRequest fetch = FetchRequest.createFetchRequest();

        fetch.addAttribute(
            AXSchemaType.FIRSTNAME.getAlias(), AXSchemaType.FIRSTNAME.getNamespace(), true);
        fetch.addAttribute(
            AXSchemaType.LASTNAME.getAlias(), AXSchemaType.LASTNAME.getNamespace(), true);
        fetch.addAttribute(AXSchemaType.EMAIL.getAlias(), AXSchemaType.EMAIL.getNamespace(), true);
        fetch.addAttribute(
            AXSchemaType.COUNTRY.getAlias(), AXSchemaType.COUNTRY.getNamespace(), true);
        fetch.addAttribute(
            AXSchemaType.LANGUAGE.getAlias(), AXSchemaType.LANGUAGE.getNamespace(), true);

        // wants up to three email addresses
        fetch.setCount(AXSchemaType.EMAIL.getAlias(), 3);

        authReq.addExtension(fetch);
      }

      if (!discovered.isVersion2()) {
        // Option 1: GET HTTP-redirect to the OpenID Provider endpoint
        // The only method supported in OpenID 1.x
        // redirect-URL usually limited ~2048 bytes
        httpResp.sendRedirect(authReq.getDestinationUrl(true));
        return null;

      } else {
        // Option 2: HTML FORM Redirection (Allows payloads >2048 bytes)

        Object OPEndpoint = authReq.getDestinationUrl(false);

        ServletOutputStream out = httpResp.getOutputStream();

        httpResp.setContentType("text/html; charset=UTF-8");
        httpResp.addHeader("pragma", "no-cache");
        httpResp.addHeader("Cache-Control", "no-cache");

        out.println("<html xmlns=\"http://www.w3.org/1999/xhtml\">");
        out.println("<head>");
        out.println("    <title>OpenID HTML FORM Redirection</title>");
        out.println("</head>");
        out.println("<body onload=\"document.forms['openid-form-redirection'].submit();\">");
        out.println(
            "    <form name=\"openid-form-redirection\" action=\""
                + OPEndpoint
                + "\" method=\"post\" accept-charset=\"utf-8\">");

        Map<String, String> parameterMap = authReq.getParameterMap();
        for (Entry<String, String> entry : parameterMap.entrySet()) {
          out.println(
              "	<input type=\"hidden\" name=\""
                  + entry.getKey()
                  + "\" value=\""
                  + entry.getValue()
                  + "\"/>");
        }

        out.println("        <button type=\"submit\">Continue...</button>");
        out.println("    </form>");
        out.println("</body>");
        out.println("</html>");

        out.flush();
      }
    } catch (OpenIDException e) {
      // present error to the user
      LOG.debug("OpenIDException", e);

      ServletOutputStream out = httpResp.getOutputStream();
      httpResp.setContentType("text/html; charset=\"UTF-8\"");
      httpResp.addHeader("pragma", "no-cache");
      httpResp.addHeader("Cache-Control", "no-cache");

      httpResp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);

      out.print("<html><head>");
      out.print("<title>OpenIDServlet Error</title>");
      out.print("<link rel=\"stylesheet\" type=\"text/css\" href=\"error.css\"></link></head>");
      out.print("<body><div id=\"container\"><h1>Error found</h1>");

      out.print("<h2>Message:");
      out.print(e.getMessage());
      out.print("</h2>");

      Throwable t = e.getCause();
      if (t != null) {
        // t can be null
        out.print(HTTPUtils.printStackTraceHTML(t));
      }

      out.print("</div></body></html>");
    }

    return null;
  }