Closing a TCP/IP component connection the right way

[rlebeau]

I am always checking if the connection is on via the "Connected" method.

You should not be doing that. Just have your timer/thread read normally and let Indy raise an exception if the connection is closed.

My question is, is that enough to know that the connection has been lost, or do I need to read from the socket to raise the proper errors accordingly?

Since Indy uses blocking sockets, a socket read is necessary. But Indy will read from the socket for you when its InputBuffer doesn't have enough bytes to satisfy a read operation. You don't need to read from the socket yourself, such as with the Connected() method (which does a socket read internally).

Knowing that the client app should not raise exceptions in the user's face everything should be handled internally.

Simply wrap any read/write operation you perform in a try..except (Pascal) or try..catch (C++) block. Indy uses exceptions for all of its error reporting.