public override async Task OnConnected()
{
var name = Context.User.Identity.Name;
using (var db = new UserContext())
{
var user = db.Users
.Include(u => u.Connections)
.SingleOrDefault(u => u.UserName == name);
if (user == null)
{
user = new User
{
UserName = name,
Connections = new List<Connection>()
};
db.Users.Add(user);
}
user.Connections.Add(new Connection
{
ConnectionId = Context.ConnectionId,
UserAgent = Context.Request.Headers["User-Agent"],
LastActivity = DateTimeOffset.UtcNow
});
await db.SaveChangesAsync();
}
}
public override async Task OnReconnected()
{
using (var db = new UserContext())
{
var connection = await db.Connections.FindAsync(Context.ConnectionId);
// Ensure the connection exists
if (connection == null)
{
db.Connections.Add(new Connection
{
ConnectionId = Context.ConnectionId,
UserAgent = Context.Request.Headers["User-Agent"],
LastActivity = DateTimeOffset.UtcNow,
UserName = Context.User.Identity.Name
});
}
else
{
connection.LastActivity = DateTimeOffset.UtcNow;
}
await db.SaveChangesAsync();
}
}
public override async Task OnDisconnected()
{
using (var db = new UserContext())
{
var connection = await db.Connections.FindAsync(Context.ConnectionId);
db.Connections.Remove(connection);
await db.SaveChangesAsync();
}
}
private void Check()
{
using (var db = new UserContext())
{
// Get all connections on this node and update the activity
foreach (var trackedConnection in _heartbeat.GetConnections())
{
if (!trackedConnection.IsAlive)
{
continue;
}
Connection connection = db.Connections.Find(trackedConnection.ConnectionId);
// Update the client's last activity
if (connection != null)
{
connection.LastActivity = DateTimeOffset.UtcNow;
}
else
{
// We have a connection that isn't tracked in our DB!
// This should *NEVER* happen
// Debugger.Launch();
}
}
// Now check all db connections to see if there's any zombies
// Remove all connections that haven't been updated based on our threshold
var zombies = db.Connections.Where(c =>
SqlFunctions.DateDiff("ss", c.LastActivity, DateTimeOffset.UtcNow) >= _zombieThreshold);
// We're doing ToList() since there's no MARS support on azure
foreach (var connection in zombies.ToList())
{
db.Connections.Remove(connection);
}
db.SaveChanges();
}
}
