private async Task messageFrom(WebSocketConnection wsc, string msg)
{
ManagedConnection mc = null;
lock (conns)
{
mc = conns.Find(x => x.WSC.Id == wsc.Id);
}
if (mc == null)
{
await wsc.CloseIfNotClosedAsync("Where did this websocket connection come from?");
return;
}
mc.LastActiveUtc = DateTime.UtcNow;
// Diagnostic: see what happens when message handling code throws
if (msg == "BOO")
{
throw new Exception("up");
}
// Client announcing their session key as the first message
if (msg.StartsWith("SESSIONKEY "))
{
if (mc.SessionKey != null)
{
await wsc.CloseIfNotClosedAsync("Client already sent their session key");
return;
}
var sessionKey = msg.Substring(11);
var startStr = docJuggler.StartSession(sessionKey);
if (startStr == null)
{
await wsc.CloseIfNotClosedAsync("We're not expecting a session with this key");
return;
}
mc.SessionKey = sessionKey;
await wsc.SendAsync("HELLO " + startStr, CancellationToken.None);
return;
}
// Anything else: client must be past sessionkey check
if (mc.SessionKey == null)
{
await wsc.CloseIfNotClosedAsync("Don't talk until you've announced your session key");
return;
}
// Just a keepalive ping: see if session is still open?
if (msg == "PING")
{
if (!docJuggler.IsSessionOpen(mc.SessionKey))
{
await wsc.CloseIfNotClosedAsync("This is not an open session");
}
return;
}
// Client announced a change
if (msg.StartsWith("CHANGE "))
{
int ix1 = msg.IndexOf(' ', 7);
int ix2 = msg.IndexOf(' ', ix1 + 1);
if (ix2 == -1)
{
ix2 = msg.Length;
}
int revId = int.Parse(msg.Substring(7, ix1 - 7));
string selStr = msg.Substring(ix1 + 1, ix2 - ix1 - 1);
string changeStr = null;
if (ix2 != msg.Length)
{
changeStr = msg.Substring(ix2 + 1);
}
if (!docJuggler.ChangeReceived(mc.SessionKey, revId, selStr, changeStr))
{
await wsc.CloseIfNotClosedAsync("We don't like this change; your session might have expired, the doc may be gone, or the change may be invalid.");
}
return;
}
// Anything else: No.
await wsc.CloseIfNotClosedAsync("You shouldn't have said that");
}