private void handleOpenArticle(
     Request request, HttpServletResponse httpServletResponse, String target) throws Exception {
   try {
     int k1 = target.indexOf('/', 1);
     int k2 = target.indexOf('/', k1 + 1);
     String feedId = target.substring(k1 + 1, k2);
     String strSeq = target.substring(k2 + 1);
     int seq = Integer.parseInt(strSeq);
     Article article = articleDb.get(feedId, seq);
     LoginInfo loginInfo = userHelpers.getLoginInfo(request);
     // ttt2 using the link from a non-authenticated browser causes a NPE; maybe do something
     // better, e.g. sign up
     ReadArticlesColl readArticlesColl = readArticlesCollDb.get(loginInfo.userId, feedId);
     if (readArticlesColl == null) {
       readArticlesColl = new ReadArticlesColl(loginInfo.userId, feedId);
     }
     if (!readArticlesColl.isRead(seq)) {
       readArticlesColl.markRead(seq, Config.getConfig().maxSizeForReadArticles);
       readArticlesCollDb.add(readArticlesColl);
     }
     String s =
         URIUtil.encodePath(article.url)
             .replace("%3F", "?")
             .replace("%23", "#"); // ttt2 see how to do this right
     httpServletResponse.sendRedirect(s);
   } catch (Exception e) {
     WebUtils.showResult(
         String.format("Failed to get article for path %s. %s", target, e),
         "/",
         request,
         httpServletResponse);
   }
 }
 // !!! IDEA reports this as unused, but it is called from JSP
 public static String getStyle(LoginInfo loginInfo) {
   StringBuilder bld = new StringBuilder();
   bld.append("<style media=\"screen\" type=\"text/css\">\n\n");
   if (loginInfo == null) {
     bld.append(Config.getConfig().defaultStyle);
   } else {
     bld.append(loginInfo.style); // ttt3 detect broken styles and return default
   }
   bld.append("</style>\n");
   return bld.toString();
 }
  private void handleSignupPost(Request request, HttpServletResponse httpServletResponse)
      throws Exception {
    String userId = request.getParameter(PARAM_USER_ID);
    String userName = request.getParameter(PARAM_USER_NAME);
    String email = request.getParameter(PARAM_EMAIL);
    String stringPassword = request.getParameter(PARAM_PASSWORD);
    String stringPasswordConfirm = request.getParameter(PARAM_PASSWORD_CONFIRM);

    if (!stringPassword.equals(stringPasswordConfirm)) {
      WebUtils.redirectToError(
          "Mismatch between password and password confirmation", request, httpServletResponse);
      return;
    }

    SecureRandom secureRandom = new SecureRandom();
    String salt = "" + secureRandom.nextLong();
    byte[] password = User.computeHashedPassword(stringPassword, salt);
    User user = userDb.get(userId);
    if (user != null) {
      WebUtils.redirectToError(
          "There already exists a user with the ID " + userId, request, httpServletResponse);
      return;
    }

    user =
        new User(
            userId,
            userName,
            password,
            salt,
            email,
            new ArrayList<String>(),
            Config.getConfig().activateAccountsAtCreation,
            false);
    // ttt2 add confirmation by email, captcha, ...
    List<String> fieldErrors = user.checkFields();
    if (!fieldErrors.isEmpty()) {
      StringBuilder bld =
          new StringBuilder("Invalid values when trying to create user with ID ")
              .append(userId)
              .append("<br/>");
      for (String s : fieldErrors) {
        bld.append(s).append("<br/>");
      }
      WebUtils.redirectToError(bld.toString(), request, httpServletResponse);
      return;
    }

    // ttt2 2 clients can add the same userId simultaneously
    userDb.add(user);

    httpServletResponse.sendRedirect("/");
  }
  private void handleAddFeedPost(Request request, HttpServletResponse httpServletResponse)
      throws Exception {
    LOG.info("adding feed");
    User user = userHelpers.getUser(request);

    try {
      if (user == null) {
        LOG.error("User not found");
        return;
      }

      String url = request.getParameter(PARAM_NEW_FEED_URL);
      // ttt1 add some validation; probably best try to actually get data, set the title, ...
      if (url == null || url.equals("")) {
        LOG.error("New feed not specified");
        // ttt1 show some error
        return;
      }

      MessageDigest digest = MessageDigest.getInstance("MD5");
      String feedId = PrintUtils.byteArrayAsUrlString(digest.digest(url.getBytes("UTF-8")));
      feedId = feedId.substring(0, Config.getConfig().feedIdSize);

      Feed feed = feedDb.get(feedId);
      if (feed == null) {
        feed = new Feed(feedId, url);
        feedDb.add(feed);
      }

      if (user.feedIds.contains(feedId)) {
        LOG.error(String.format("Trying to add existing feed %s to user %s", feedId, user));
      } else {
        user.feedIds.add(feedId);
        userDb.updateFeeds(user);
      }
    } finally {
      httpServletResponse.sendRedirect(PATH_FEED_ADMIN);
    }
  }
  private void handleLoginPost(
      Request request, HttpServletResponse httpServletResponse, boolean secured) throws Exception {
    String userId = request.getParameter(PARAM_USER_ID);
    String password = request.getParameter(PARAM_PASSWORD);
    String rememberAccountStr = request.getParameter(PARAM_REMEMBER_ACCOUNT);
    boolean rememberAccount = Boolean.parseBoolean(rememberAccountStr);
    LoginInfo.SessionInfo sessionInfo = UserHelpers.getSessionInfo(request);

    logOut(sessionInfo.browserId);

    User user = userDb.get(userId);
    if (user == null) {
      WebUtils.redirectToError("User " + userId + " not found", request, httpServletResponse);
      return;
    }

    if (!user.checkPassword(password)) {
      WebUtils.redirectToError("Invalid password", request, httpServletResponse);
      return;
    }

    if (!user.active) {
      WebUtils.redirectToError(
          "Account for User " + userId + " needs to be activated", request, httpServletResponse);
      return;
    }

    LOG.info("Logged in user " + userId);

    sessionInfo.sessionId = null;
    if (sessionInfo.browserId == null) {
      sessionInfo.browserId = getRandomId();
    } else {
      for (LoginInfo loginInfo : loginInfoDb.getLoginsForBrowser(sessionInfo.browserId)) {
        if (userId.equals(loginInfo.userId)) {
          sessionInfo.sessionId = loginInfo.sessionId;
          break;
        }
      }
    }

    long expireOn = System.currentTimeMillis() + Config.getConfig().loginExpireInterval;
    if (sessionInfo.sessionId == null) {
      sessionInfo.sessionId = getRandomId();
      Config config = Config.getConfig();
      loginInfoDb.add(
          new LoginInfo(
              sessionInfo.browserId,
              sessionInfo.sessionId,
              userId,
              expireOn,
              rememberAccount,
              config.defaultStyle,
              config.defaultItemsPerPage,
              config.defaultFeedDateFormat));
      LOG.info(String.format("Logging in in a new session. User: %s", user));
    } else {
      loginInfoDb.updateExpireTime(sessionInfo.browserId, sessionInfo.sessionId, expireOn);
      LOG.info(String.format("Logging in in an existing session. User: %s", user));
    }

    WebUtils.saveCookies(
        httpServletResponse, secured, sessionInfo.browserId, sessionInfo.sessionId);

    httpServletResponse.sendRedirect("/");
  }