1. Sockets, part 3 (nonblocking tcp using streams)
Eric Freudenthal

2. Calls for stream sockets
Socket(): to create
Bind(): to associate with a port, or port & addr
Listen(): set a socket in a mode where it can accept
Accept(): provides a socket connected to a client
Connect(): to connect to a server socket
Read, Write(): to send/obtain data
Readv, Writev
Close(): Disconnect socket
Shutdown(): done with transmit or receive
Set non-blocking (actually a bit messy)
Poll(): wait for condition

3. Simple request/response lifecycle
Server listener
Client stream
Set non-blocking
Set non-blocking
Connect
Listen
(POLLIN)
Accept sever socket
(POLLOUT)
Accepted (server) stream
Write (part of) request
Set non-blocking
(POLLIN) no
Done?
Read (part of) request
Shutdown(SHUT_WR) no
Zero length?
(POLLOUT)
Write (part of) response
(POLLIN) no
Read (part of) response
Done? no
Close
Zero length?
Close

4. Server listener createServer() serverAction() // on POLLIN
Socket(), Bind(), set non-blocking
Record: socket needs POLLIN
serverAction() // on POLLIN
Accept()
Create ServerHandler
Set non-blocking
Listen
(POLLIN)
Accept sever socket

5. Client createClient () clientAction()
Set non-blocking
Connect
createClient ()
Socket(), non-blocking, Connect()
Record: socket needs POLLOUT
clientAction()
If for POLLOUT
Write (part of) request
If done, sensitivity now POLLIN
If for POLLIN
Read (part of) response
If zero length
Unregister POLLIN
Close socket
Free memory
(POLLOUT)
Write (part of) request no
Done?
Shutdown(SHUT_WR)
(POLLIN)
Read (part of) response no
Zero length?
Close

6. Write (part of) response
Client
createSStream()
Set non-blocking
Record: socket needs POLLIN
sstreamAction()
If for POLLIN
Read (part of) request
If zero length, sensitivity now POLLOUT
If for POLLOUT
Write (part of) response
If done
Unregister POLLOUT
Close socket
Free memory
Set non-blocking
(POLLIN)
Read (part of) request
Zero length?
(POLLOUT)
Write (part of) response no
Done?
Close