I'm studying Go for network programming. The problem is Go documentation is too simple. For example， I don't know when to use net.DialTCP, and when to use TCPListener object to AcceptTCP, what's the difference? How about client communicate with another client? Not client to server.
In Go, you use the Dial function from net to connect to a remote machine.
net.Dial("tcp","google.com:80")
net.Dial("udp","tracker.thepiratebay.org:6969")
net.Dial("ip","kremvax.su")
net.Dial("unix","/dev/log")
This gives you an abstract Conn object that represents the connection you just established. Conn implements the ReadWriteCloser interface from io and a couple of other functions. You can use this object to send and receive data.
To listen, i.e. open a port, you use the Listen function from net. Calling Listen gives you a Listener object. Use Accept to accept incoming connections. Accept returns another Conn object that can be used as above.
ls, err := net.Listen("tcp",":1337")
if err != nil {
// port probably blocked, insert error handling here
}
conn, err := ls.Accept()
if err != nil {
// error handling
}
conn.Write("Hello, world!")
These functions give you more control over TCP connections. I suggest you to only use them if they are definitly needed for your program as Dial and Listen are simpler, more generic and easily allow you to adapt your program to other types of network connections.
net.DialTCP is used on the client side to create a connection to remote server.
net.TCPListener.AcceptTCP is used on the server side to accept new connection (possibly initiated by net.DialTCP if client is written in Go). Note that listener may accept multiple connections, one by one, thus serving multiple clients at once (e.g. each in different goroutine).
Depending on whether you are writing client or server, you use net.DialTCP or net.TCPListener
Maybe you should learn about network programming in general first? Then these would make more sense I think.