The Go Programming Language

8.3 Example: Concurrent Echo Server

The clock server used one goroutine per connection. In this section, we’ll build an echo server that uses multiple goroutines per connection. Most echo servers merely write whatever they read, which can be done with this trivial version of handleConn:

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func handleConn(c net.Conn) {
    io.Copy(c, c) // NOTE: ignoring errors
    c.Close()
}

A more interesting echo server might simulate the reverberations of a real echo, with the response loud at first ("HELLO!"), then moderate ("Hello!") after a delay, then quiet ("hello!") before fading to nothing, as in this version of handleConn:

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gopl.io/ch8/reverb1

func echo(c net.Conn, shout string, delay time.Duration) ...