examples: add TCP echo server using os.notify (#10481)

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Miccah 2021-06-16 11:15:56 -05:00 committed by GitHub
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import os
import os.notify
import net
import time
// This example demonstrates a single threaded TCP server using os.notify to be
// notified of events on file descriptors. You can connect to the server using
// netcat in separate shells, for example: `nc localhost 9001`
fn main() {
$if !linux {
eprintln('This example only works on Linux')
exit(1)
}
// create TCP listener
mut listener := net.listen_tcp(.ip, 'localhost:9001') ?
defer {
listener.close() or {}
}
addr := listener.addr() ?
eprintln('Listening on $addr')
eprintln('Type `stop` to stop the server')
// create file descriptor notifier
mut notifier := notify.new() ?
defer {
notifier.close() or {}
}
notifier.add(os.stdin().fd, .read) ?
notifier.add(listener.sock.handle, .read) ?
for {
for event in notifier.wait(time.infinite) {
match event.fd {
listener.sock.handle {
// someone is trying to connect
eprint('trying to connect.. ')
if conn := listener.accept() {
if _ := notifier.add(conn.sock.handle, .read | .peer_hangup) {
eprintln('connected')
} else {
eprintln('error adding to notifier: $err')
}
} else {
eprintln('unable to accept: $err')
}
}
0 {
// stdin
s, _ := os.fd_read(event.fd, 10)
if s == 'stop\n' {
eprintln('stopping')
return
}
}
else {
// remote connection
if event.kind.has(.peer_hangup) {
if _ := notifier.remove(event.fd) {
eprintln('remote disconnected')
} else {
eprintln('error removing from notifier: $err')
}
} else {
s, _ := os.fd_read(event.fd, 10)
os.fd_write(event.fd, s)
}
}
}
}
}
}