页面刷新时 SignalR

Question

I am using SignalR to share user's live location and I run into a big problem and I can't find a good idea to get rid of a problem. The problem is that every time a user starts sharing the location I add them into the database table in which I keep the people sharing their location, but if this user refreshes the page I don't know this and they remains as a user that shares the location in the database. If they just leaves the page or press a stop button they are erased from the database.

Any idea on how to solve this problem if it is possible?

Answer 1

but if this user refreshes the page I don't know this

You can use Hub.OnConnectedAsync Method to get the refreshed Connectionid, and according to the current user update the refreshed Connectionid to the database, code like below:

public override async Task OnConnectedAsync()
        {
            //get the connection id
            var connectionid = Context.ConnectionId;
            //get the username or userid
            var username = Context.User.Identity.Name;
            var userId = Guid.Parse(Context.User.FindFirstValue(ClaimTypes.NameIdentifier));

            //update the current user's connectionid to database
            var CId = _context.UserIdToCId.Find(userId);
            CId.ConnectionId = connectionid;
            _context.Update(CId);
            await _context.SaveChangesAsync();
            await base.OnConnectedAsync();
        }

Note Remember to go to the database to check the latest ConnectionId of this person before share user's live location.