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---
title: Setting And Reading Cookies
order: 16
layout: page
---
[[setting-and-reading-cookies]]
= Setting And Reading Cookies
You can easily read and write
http://en.wikipedia.org/wiki/HTTP_cookie[cookies] from both the server
and the client side in Vaadin, with one caveat: Cookies are not possible
if you enable Push using WebSocket (see tickets
http://dev.vaadin.com/ticket/11808[11808] and
http://dev.vaadin.com/ticket/12518[12518]). Beginning in Vaadin 7.6,
cookies can be used with the WEBSOCKET_XHR transport type.
The
https://vaadin.com/api/7.0.3/com/vaadin/server/VaadinRequest.html[VaadinRequest]
class gives easy access to the collection of cookies bundled with each
http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol[HTTP] request.
Each cookie is represented as instances of the
http://docs.oracle.com/javaee/6/api/javax/servlet/http/Cookie.html[javax.servlet.http.Cookie]
class defined by the Java
http://en.wikipedia.org/wiki/Java_Servlet[Servlet]http://www.jcp.org/en/jsr/detail?id=315[spec].
To read a cookie on the server side you can request the cookies from the
current request like so:
[source,java]
....
// Fetch all cookies
Cookie[] cookies = VaadinService.getCurrentRequest().getCookies();
....
_That will fetch all currently defined cookies. You can then iterate
over them to find the cookie you are looking for._
To add a new cookie or update an already defined cookie you can do the
following:
[source,java]
....
// Create a new cookie
Cookie myCookie = new Cookie("cookie-name", "cookie-value");
// Make cookie expire in 2 minutes
myCookie.setMaxAge(120);
// Set the cookie path.
myCookie.setPath(VaadinService.getCurrentRequest().getContextPath());
// Save cookie
VaadinService.getCurrentResponse().addCookie(myCookie);
....
Here is a full example of utilizing cookies on the server side by
storing a a value from a `TextField` in a cookie for later use.
[source,java]
....
public class CookieMonsterUI extends UI {
private static final String NAME_COOKIE = "name";
@Override
protected void init(VaadinRequest request) {
final VerticalLayout layout = new VerticalLayout(); layout.setMargin(true);
setContent(layout);
final TextField nameField = new TextField(); layout.addComponent(nameField);
// Read previously stored cookie value
Cookie nameCookie = getCookieByName(NAME_COOKIE);
if (getCookieByName(NAME_COOKIE) != null) {
nameField.setValue(nameCookie.getValue());
}
Button button = new Button("Store name in cookie"); button.addClickListener(new Button.ClickListener() {
@Override
public void buttonClick(ClickEvent event) {
String name = nameField.getValue();
// See if name cookie is already set
Cookie nameCookie = getCookieByName(NAME_COOKIE);
if (nameCookie != null) {
String oldName = nameCookie.getValue();
nameCookie.setValue(name);
Notification.show("Updated name in cookie from " + oldName + " to " + name);
} else {
// Create a new cookie
nameCookie = new Cookie(NAME_COOKIE, name);
nameCookie .setComment("Cookie for storing the name of the user");
Notification.show("Stored name " + name + " in cookie");
}
// Make cookie expire in 2 minutes
nameCookie.setMaxAge(120);
// Set the cookie path.
nameCookie.setPath(VaadinService.getCurrentRequest() .getContextPath());
// Save cookie
VaadinService.getCurrentResponse().addCookie(nameCookie);
}
});
layout.addComponent(button);
}
private Cookie getCookieByName(String name) {
// Fetch all cookies from the request
Cookie[] cookies = VaadinService.getCurrentRequest().getCookies();
// Iterate to find cookie by its name
for (Cookie cookie : cookies) {
if (name.equals(cookie.getName())) {
return cookie;
}
}
return null;
}
}
....
Finally if you need to read a cookie from client-side code, you can use
the `Cookies` class like so:
[source,java]
....
// Read name from cookie
String name = Cookies.getCookie("name");
// Write new value to cookie
Cookies.setCookie("name", "Some other value");
....
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