private void DeleteAllExpiredSessionsAndMessages()
{
CryptoChatEntities context = new CryptoChatEntities();
DateTime minAllowedLastActivityTime =
DateTime.Now.AddSeconds(-Settings.Default.HttpSessionTimeoutSeconds);
// Delete any expired chat sessions in the DB
string deleteChatSessionsSQL =
"DELETE FROM ChatSessions " +
"FROM Users u JOIN ChatSessions s " +
" ON (u.UserId = s.FromUserId or u.UserId = s.ToUserId) " +
"WHERE LastActivity < {0}";
context.ExecuteStoreCommand(deleteChatSessionsSQL,
new object[] { minAllowedLastActivityTime });
// Delete any expired messages in the DB
string deleteMessagesSQL =
"DELETE FROM Messages " +
"FROM Users u JOIN Messages m ON (u.UserId = m.ToUserId) " +
"WHERE LastActivity < {0}";
context.ExecuteStoreCommand(deleteMessagesSQL,
new object[] { minAllowedLastActivityTime });
// Send notifications about all users whose sessions were expired
var usersWithExpiredSession =
from u in context.Users
where u.LastActivity < minAllowedLastActivityTime &&
u.SessionKey != null
select u;
foreach (var user in usersWithExpiredSession)
{
user.SessionKey = null;
MobileCryptoChatService.SendMessageToAllOnlineUsers(user,
MessageType.MSG_USER_OFFLINE, "User lost connection with the server.");
}
context.SaveChanges();
}
private void DeleteChatSession(User senderUser, User recipientUser)
{
CryptoChatEntities context = new CryptoChatEntities();
// Delete any existing chat sessions between the users
string deleteChatSessionsSQL = "DELETE FROM ChatSessions WHERE " +
"(FromUserId={0} and ToUserId={1}) or (FromUserId={1} and ToUserId={0})";
context.ExecuteStoreCommand(deleteChatSessionsSQL,
new object[] { senderUser.UserId, recipientUser.UserId });
// Delete any waiting chat messages between the users
string msgTypesToDelete =
"'" + MessageType.MSG_CHALLENGE.ToString() + "'," +
"'" + MessageType.MSG_RESPONSE.ToString() + "'," +
"'" + MessageType.MSG_START_CHAT.ToString() + "'," +
"'" + MessageType.MSG_CANCEL_CHAT.ToString() + "'," +
"'" + MessageType.MSG_CHAT_MESSAGE.ToString() + "'";
string deleteMessagesSQL = "DELETE FROM Messages WHERE " +
"((FromUserId={0} and ToUserId={1}) or (FromUserId={1} and ToUserId={0})) AND " +
"(MsgType in (" + msgTypesToDelete + "))";
context.ExecuteStoreCommand(deleteMessagesSQL,
new object[] { senderUser.UserId, recipientUser.UserId });
}
private void DeleteWaitingMessagesAndSessions(User recipientUser)
{
CryptoChatEntities context = new CryptoChatEntities();
// Delete any waiting messages for the user
string deleteMessagesSQL = "DELETE FROM Messages WHERE ToUserId={0}";
context.ExecuteStoreCommand(deleteMessagesSQL,
new object[] { recipientUser.UserId });
// Delete any existing chat sessions associated with the user
string deleteChatSessionsSQL = "DELETE FROM ChatSessions WHERE " +
"FromUserId={0} or ToUserId={0}";
context.ExecuteStoreCommand(deleteChatSessionsSQL,
new object[] { recipientUser.UserId });
}
public StatusResponse LogoutUser(string sessionID)
{
ExecuteAndHandleExceptions(() =>
{
User user = CheckUserSession(sessionID);
CryptoChatEntities context = new CryptoChatEntities();
int updatedSessionsCount = context.ExecuteStoreCommand(
"UPDATE Users SET SessionKey=null WHERE SessionKey={0}",
new object[] { sessionID });
if (updatedSessionsCount != 1)
{
throw new ErrorResponseException(HttpStatusCode.InternalServerError,
"ERR_LOGOUT_FAIL", "Logout failed unexpectedly.");
}
// Session sucessfully removed from DB (logout was successfull)
DeleteWaitingMessagesAndSessions(user);
// Send the "user online" notification to all online users
SendMessageToAllOnlineUsers(user,
MessageType.MSG_USER_OFFLINE, "User left the system.");
});
return new StatusResponse();
}