I am calling a void function using jquery ajax in mvc3. In that function when the Session is out then also it will come to success function of ajax. I need to know whether the Session is available or not before sending the request or inside the success function of ajax.
controller Action:
protected override void Save(Query query, string queryTitle)
{
}
Why not catch the expiry of the session on the server, return an HTTP 401 Unauthorized, then check for this response in jquery and pop up a "Your session has expired, please log in again" page?
The code you need on the initial server call is:
protected void Save(Query query, string queryTitle)
{
// would probably be better to refactor this bit out into its own method
string sCookieHeader = Request.Headers["Cookie"];
if (Context.Session != null
&& Context.Session.IsNewSession
&& sCookieHeader != null
&& sCookieHeader.IndexOf("ASP.NET_SessionId") >= 0)
{
// session has expired
if (Request.IsAuthenticated)
{
FormsAuthentication.SignOut();
}
Response.StatusCode = 401
}
else
{
// we're authenticated, so do the save
}
}
and on the client:
$.ajax(serverUrl, {
data: dataToSave,
statusCode: {
200: function(response) {
// all good, continue
401: function (response) {
// session expired!
// show login box
// make ajax call to reauthenticate
// call save method again
},
});
Your reauthentication call would look something like this:
public ActionResult Reauthenticate(username, password)
{
if (IsValidUser(username, password))
{
// sometimes used to persist user roles
string userData = string.Join("|",GetCustomUserRoles());
FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(
1, // ticket version
username, // authenticated username
DateTime.Now, // issueDate
DateTime.Now.AddMinutes(30), // expiryDate
isPersistent, // true to persist across browser sessions
userData, // can be used to store additional user data
FormsAuthentication.FormsCookiePath); // the path for the cookie
// Encrypt the ticket using the machine key
string encryptedTicket = FormsAuthentication.Encrypt(ticket);
// Add the cookie to the request to save it
HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket);
cookie.HttpOnly = true;
Response.Cookies.Add(cookie);
}
}
(Adapted from How to set HTTP status code from ASP.NET MVC 3?)
Why not try this ?
public void Save()
{
if (Session.IsNewSession)
{
throw new Exception("This session was just created.");
}
//Go on with save matter...
}
This should return a status 500 on your AJAX function and should cause the response to fall in the fail method you defined.
Another way is to setInterval() on the client that continually sends a dummy request to the server to keep the session alive, at least when the user is editing. This might be the best way to prevent them user from losing work. You could also use this to detect loss connectivity.
When the page is loaded first time , pass the current SessionId to the client side and assign to the local javascript variable.Next have a method which will return the current SessionId before making the Save method call from the AJAX , compare the local variable against the Session Id you have received.
public string GetCurrentSessionId(){
return HttpContext.Current.Session.SessionId;
}
Javascript function
$.ajax({
Url : 'GetCurrentSessionId',
success : function(result){
if(result === "LOCALSESSIONID")
CALL THE SAVE METHOD
else
alert('Session is expired');
}
});
