Package com.google.gwt.user.server.rpc

Class XsrfTokenServiceServlet

  • All Implemented Interfaces:
    RemoteService, XsrfTokenService, SerializationPolicyProvider, java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig
    public class XsrfTokenServiceServlet
extends RemoteServiceServlet
implements XsrfTokenService
    EXPERIMENTAL and subject to change. Do not use this in production code.

    RPC service to generate XSRF tokens.

    Sample use of XsrfTokenService:

    1. Add XsrfTokenServiceServlet to web.xml: 
       <servlet>
   <servlet-name>xsrf</servlet-name>
   <servlet-class>
     com.google.gwt.user.server.rpc.XsrfTokenServiceServlet
   </servlet-class>
 </servlet>
 <servlet-mapping>
   <servlet-name>xsrf</servlet-name>
   <url-pattern>/gwt/xsrf</url-pattern>
 </servlet-mapping>
    2. Specify session cookie name that is used for authentication. MD5 hash of the session cookie's value will be used as an XSRF token: 
       <context-param>
   <param-name>gwt.xsrf.session_cookie_name</param-name>
   <param-value>JSESSIONID</param-value>
 </context-param>
    3. To enforce XSRF token validation on each method call either mark RPC interface as XSRF protected using XsrfProtect annotation or extend XsrfProtectedService instead of RemoteService. Use NoXsrfProtect to mark methods as not requiring XSRF protection: 
       public interface MyRpcService extends XsrfProtectedService {
   public void doStuff();
 }
    4. Ensure that RPC's servlet implementation extends XsrfProtectedServiceServlet instead of RemoteServiceServlet: 
       public class MyRpcServiceServlet extends XsrfProtectedServiceServlet
     implements MyRpcService {

   public void doStuff() {
     // ...
   }
 }
    5. Obtain XsrfToken and set it on the RPC end point: 
       XsrfTokenServiceAsync xsrf = (XsrfTokenServiceAsync)GWT.create(XsrfTokenService.class);

 ((ServiceDefTarget)xsrf).setServiceEntryPoint(GWT.getModuleBaseURL() + "xsrf");

 xsrf.getNewXsrfToken(new AsyncCallback<XsrfToken>() {
   public void onSuccess(XsrfToken result) {
     MyRpcServiceAsync rpc = (MyRpcServiceAsync)GWT.create(MyRpcService.class);
     ((HasRpcToken) rpc).setRpcToken(result);
     // make XSRF protected RPC call
     rpc.doStuff(new AsyncCallback<Void>() {
       // ...
     });

   }

   public void onFailure(Throwable caught) {
     try {
       throw caught;
     } catch (RpcTokenException e) {
       // Can be thrown for several reasons:
       //   - duplicate session cookie, which may be a sign of a cookie
       //     overwrite attack
       //   - XSRF token cannot be generated because session cookie isn't
       //     present
     } catch (Throwable e) {
       // unexpected
     }
 });

    See Also:
    XsrfProtectedServiceServlet, XsrfProtect, NoXsrfProtect, Serialized Form

    • Field Detail

      • COOKIE_NAME_PARAM

        public static final java.lang.String COOKIE_NAME_PARAM
        Session cookie name initialization parameter.
        See Also:
        Constant Field Values

      • COOKIE_NAME_NOT_SET_ERROR_MSG

        static final java.lang.String COOKIE_NAME_NOT_SET_ERROR_MSG
        See Also:
        Constant Field Values

    • Constructor Detail

      • XsrfTokenServiceServlet

        public XsrfTokenServiceServlet()
        Default constructor.

      • XsrfTokenServiceServlet

        public XsrfTokenServiceServlet​(java.lang.String sessionCookieName)
        Alternative constructor that accepts session cookie name instead of getting it from ServletConfig or ServletContext.

    • Method Detail

      • init

        public void init()
        Servlet initialization.
        Overrides:
        init in class javax.servlet.GenericServlet