examples: add net_udp_server_and_client.v

examples/net_udp_server_and_client.v

@@ -0,0 +1,44 @@
+import os
+import os.cmdline
+import net
+
+fn main() {
+	println('Usage: net_udp_server_and_client [-l] [-p 5000]')
+	println('     -l      - act as a server and listen')
+	println('     -p XXXX - custom port number')
+	println('------------------------------------------')
+	is_server := '-l' in os.args
+	port := cmdline.option(os.args, '-p', '40001').int()
+	mut buf := []byte{len: 100}
+	if is_server {
+		println('UDP echo server, listening for udp packets on port: $port')
+		mut c := net.listen_udp(port) ?
+		for {
+			read, addr := c.read(mut buf) or { continue }
+			println('received $read bytes from $addr')
+			c.write_to(addr, buf[..read]) or {
+				println('Server: connection dropped')
+				continue
+			}
+		}
+	} else {
+		println('UDP client, sending packets to port: ${port}.\nType `exit` to exit.')
+		mut c := net.dial_udp('localhost', 'localhost:$port') ?
+		for {
+			mut line := os.input('client > ')
+			match line {
+				'' {
+					line = '\n'
+				}
+				'exit' {
+					println('goodbye.')
+					exit(0)
+				}
+				else {}
+			}
+			c.write_str(line) ?
+			read, _ := c.read(mut buf) ?
+			println('server : ' + buf[0..read].bytestr())
+		}
+	}
+}

vlib/net/udp.v

@@ -3,10 +3,16 @@ module net
 import time
 
 const (
-	udp_default_read_timeout  = 30 * time.second
+	udp_default_read_timeout  = time.second / 10
-	udp_default_write_timeout = 30 * time.second
+	udp_default_write_timeout = time.second / 10
 )
 
+struct UdpSocket {
+	handle int
+	l      Addr
+	r      ?Addr
+}
+
 pub struct UdpConn {
 pub mut:
 	sock UdpSocket
@@ -168,12 +174,6 @@ pub fn listen_udp(port int) ?&UdpConn {
 	}
 }
 
-struct UdpSocket {
-	handle int
-	l      Addr
-	r      ?Addr
-}
-
 fn new_udp_socket(local_port int) ?&UdpSocket {
 	sockfd := socket_error(C.socket(SocketFamily.inet, SocketType.udp, 0)) ?
 	mut s := &UdpSocket{