public LtiSession TryToExtractSessionFromRequest(HttpRequestBase request)
{
LtiSession res = new LtiSession();
if (request.Form["ltiSessionId"] != null && request.Form["ltiSessionId"].ToString() != "")
{
res = GetAndRefreshSession(Guid.Parse(request.Form["ltiSessionId"].ToString()), request.UserHostAddress);
}
return res;
}
public LtiSession GetAndRefreshSession(Guid ltiSessionId, string userHostAddress)
{
LtiSession res = new LtiSession();
try
{
LtiSession existingLtiSession = null;
existingLtiSession = (from s in _dbContext.LtiSessions
where s.Id == ltiSessionId
select s).SingleOrDefault();
if (existingLtiSession != null && existingLtiSession.UserHostAddress == userHostAddress)
{
if (existingLtiSession.Timestamp < DateTime.Now.AddDays(-1))
{
// Remove the session if it is older than a day.
_dbContext.LtiSessions.Remove(existingLtiSession);
_dbContext.SaveChanges();
}
else
{
RefreshSession(existingLtiSession);
res = existingLtiSession;
res.Valid = true;
res.DeserializeLtiRequest();
}
}
}
catch (Exception e)
{
_log.Error("Failed to get session: " + e.Message);
throw new Exception("Failed to get session.", e);
}
return res;
}
public LtiSession CreateValidSession(LtiSession session)
{
LtiSession res =
(from s in _dbContext.LtiSessions
where s.ConsumerKey == session.LtiRequest.ConsumerKey &&
s.ContextId == session.LtiRequest.ContextId &&
s.UserId == session.LtiRequest.UserId
select s).SingleOrDefault();
if (res != null)
{
_dbContext.LtiSessions.Remove(res);
_dbContext.SaveChanges();
}
res = new LtiSession()
{
ConsumerKey = session.LtiRequest.ConsumerKey,
ContextId = session.LtiRequest.ContextId,
UserId = session.LtiRequest.UserId,
Timestamp = DateTime.Now,
LtiRequest = session.LtiRequest,
UserHostAddress = session.UserHostAddress
};
res.SerializeLtiRequest();
res = _dbContext.LtiSessions.Add(res);
_dbContext.SaveChanges();
if (res == null)
{
throw new Exception("Failed to fetch newly created LTI session.");
}
return res;
}
public void UpdateLtiRequest(LtiSession session, LtiRequest ltiRequest)
{
session.LtiRequest = ltiRequest;
_dbContext.SaveChanges();
}
public void RefreshSession(LtiSession session)
{
session.Timestamp = DateTime.Now;
_dbContext.SaveChanges();
}
public ITool SetSession(LtiSession session)
{
_session = session;
return this; // For call chaining
}
