udp

stable

UDP socket plugin for sending and receiving datagrams. Provides a UdpSocket class with full control over binding, timeouts, broadcast, TTL, and blocking mode.

use plugin udp::{UdpSocket, send_to, recv, …}

13 functions Networking

Runs with the native Zolo host

Plugin snippets can be edited in the Playground, but native capabilities are executed locally with the Zolo CLI.

/ filter jk navigate Esc clear

Functions (13)

UdpSocket Creates a UDP socket and binds it to the given address.
send_to Sends data as a string to the specified remote addr.
recv Blocks until a datagram arrives and returns a table with data (string) and addr (source address string).
local_addr Returns the local address the socket is bound to, e.g.
set_nonblocking Switches the socket between blocking (default) and non-blocking mode.
set_broadcast Enables or disables the SO_BROADCAST socket option, required before sending to broadcast addresses like 255.255.255.255.
set_read_timeout Sets a read timeout in milliseconds.
set_write_timeout Sets a write timeout in milliseconds.
connect Associates a default remote address with the socket.
send Sends data to the address previously set with connect.
peek Reads up to buf_size bytes without removing the datagram from the queue.
set_ttl Sets the IP Time-To-Live (hop count) for outgoing packets.
ttl Returns the current IP TTL value set on the socket.

From import to result

01Import only what you use
02Copy the smallest example
03Run it with the Zolo CLI

UdpSocket(bind_addr) → handle

Creates a UDP socket and binds it to the given address.

Creates a UDP socket and binds it to the given address. Use "0.0.0.0:0" to bind to any available port, or specify a port like "0.0.0.0:9000".

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:9000")
print("Listening on {sock.local_addr()}")

send_to(socket, data, addr) → int

Sends data as a string to the specified remote addr.

Sends data as a string to the specified remote addr. Returns the number of bytes sent.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
let sent = sock.send_to("hello", "127.0.0.1:9000")
print("Sent {sent} bytes")

recv(socket, buf_size) → table

Blocks until a datagram arrives and returns a table with data (string) and addr (source address string).

Blocks until a datagram arrives and returns a table with data (string) and addr (source address string). The buf_size argument sets the maximum number of bytes to read.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:9000")
let msg = sock.recv(1024)
print("From {msg["addr"]}: {msg["data"]}")

local_addr(socket) → string

Returns the local address the socket is bound to, e.g.

Returns the local address the socket is bound to, e.g. "0.0.0.0:9000".

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
print(sock.local_addr())

set_nonblocking(socket, nonblocking) → nil

Switches the socket between blocking (default) and non-blocking mode.

Switches the socket between blocking (default) and non-blocking mode. In non-blocking mode, recv returns immediately if no data is available.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:9000")
sock.set_nonblocking(true)

set_broadcast(socket, broadcast) → nil

Enables or disables the SO_BROADCAST socket option, required before sending to broadcast addresses like 255.255.255.255.

Enables or disables the SO_BROADCAST socket option, required before sending to broadcast addresses like 255.255.255.255.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
sock.set_broadcast(true)
sock.send_to("ping", "255.255.255.255:9001")

set_read_timeout(socket, timeout_ms) → nil

Sets a read timeout in milliseconds.

Sets a read timeout in milliseconds. Pass 0 or a negative value to remove the timeout (blocking forever). After the timeout elapses, recv will return an error.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:9000")
sock.set_read_timeout(5000)

set_write_timeout(socket, timeout_ms) → nil

Sets a write timeout in milliseconds.

Sets a write timeout in milliseconds. Pass 0 or a negative value to clear the timeout.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
sock.set_write_timeout(3000)

connect(socket, addr) → nil

Associates a default remote address with the socket.

Associates a default remote address with the socket. After calling this, you can use send and recv without specifying an address each time.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
sock.connect("127.0.0.1:9000")
sock.send("ping")

send(socket, data) → int

Sends data to the address previously set with connect.

Sends data to the address previously set with connect. Returns the number of bytes sent.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
sock.connect("127.0.0.1:9000")
let n = sock.send("hello world")
print("Sent {n} bytes")

peek(socket, buf_size) → table

Reads up to buf_size bytes without removing the datagram from the queue.

Reads up to buf_size bytes without removing the datagram from the queue. Returns the same #{"data": ..., "addr": ...} table as recv.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:9000")
let preview = sock.peek(64)
print("Peek from {preview["addr"]}: {preview["data"]}")

set_ttl(socket, ttl) → nil

Sets the IP Time-To-Live (hop count) for outgoing packets.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
sock.set_ttl(64)

ttl(socket) → int

Returns the current IP TTL value set on the socket.

use plugin udp::{UdpSocket}

let sock = UdpSocket("0.0.0.0:0")
print("TTL: {sock.ttl()}")

View source code

udp