Using DWR from XUL applications



DWR is usable from XUL applications except that DWR can't find cookies in the standard way because document.cookie is not available to XUL applications.



You can allow use of DWR from XUL by making the following change to engine.js. It's not an official part of DWR because we don't regularly test with XUL applications.



The easy way to make this change is simply to load the following script after engine.js


/** @private What is our session id? */
dwr.engine._getJSessionId = function() {
  if (typeof document.cookie == 'undefined') { // not in a classic html so guessing xul
    netscape.security.PrivilegeManager.enablePrivilege('UniversalXPConnect');
    var cookieManager = Components.classes["@mozilla.org/cookiemanager;1"].getService(Components.interfaces.nsICookieManager2);
    var iter = cookieManager.enumerator;
    while (iter.hasMoreElements()) {
      var cookie = iter.getNext();
      if (cookie instanceof Components.interfaces.nsICookie) {
        if (cookie.name == dwr.engine._sessionCookieName)
          return cookie.value;
      }
    }
  }
  else {
    var cookies = document.cookie.split(';');
    for (var i = 0; i < cookies.length; i++) {
      var cookie = cookies[i];
      while (cookie.charAt(0) == ' ')
        cookie = cookie.substring(1, cookie.length);
      if (cookie.indexOf(dwr.engine._sessionCookieName + "=") == 0) {
        return cookie.substring(dwr.engine._sessionCookieName.length + 1, cookie.length);
        }
      }
  }
  return "";
}

We're grateful to S.P�r�s-Labourdette for this submission to the DWR mailing list.