Accessing web page and browser information

Vaadin 7 includes a new Page class offering access to various client-side information and events concerning the web page and browser window in which the Vaadin UI resides. The Page instance corresponding to a given UI is accessed via the getPage() method of the UI or using a static method Page.getCurrent().

You can access the browser window size and add size change listeners:

Page page = someUI.getPage();
page.addBrowserWindowResizeListener(new BrowserWindowResizeListener() {
  public void browserWindowResized(BrowserWindowResizeEvent event) {
    Notification.show("Window width=" + event.getWidth() + ", height=" + event.getHeight());
  }
});

You can access the optional fragment part of the location URI and add fragment change listeners:

page.setUriFragment(page.getUriFragment() + "foo");
page.addUriFragmentChangedListener(new UriFragmentChangedListener() {
  public void uriFragmentChanged(UriFragmentChangedEvent event) {
    Notification.show("Fragment=" + event.getUriFragment());
  }
});

Note: HTML is disabled by default in Notifications, but can be enabled with setHtmlContentAllowed(true). When enabled, you can use any HTML markup in the caption and description of a notification. If it is in any way possible to get the notification content from user input, you should either disallow HTML or sanitize the content carefully, as noted in "Sanitizing User Input to Prevent Cross-Site Scripting".

You can access client browser details:

Notification.show("IP" + browser.getAddress() +
                "User-Agent:" + browser.getBrowserApplication() +
                "Linux: " + browser.isLinux());

Live Demo

Note: If you are using a reverse proxy, you must get the value X-Forwarded-For from request headers. You cannot get a browser name, but you can check which browser are using.