class UDPSocket
Overview
A User Datagram Protocol (UDP) socket.
UDP runs on top of the Internet Protocol (IP) and was developed for applications that do not require reliability, acknowledgement, or flow control features at the transport layer. This simple protocol provides transport layer addressing in the form of UDP ports and an optional checksum capability.
UDP is a very simple protocol. Messages, so called datagrams, are sent to other hosts on an IP network without the need to set up special transmission channels or data paths beforehand. The UDP socket only needs to be opened for communication. It listens for incoming messages and sends outgoing messages on request.
This implementation supports both IPv4 and IPv6 addresses. For IPv4 addresses you must use
Socket::Family::INET
family (default) or Socket::Family::INET6
for IPv6 # addresses.
Usage example:
require "socket"
# Create server
server = UDPSocket.new
server.bind "localhost", 1234
# Create client and connect to server
client = UDPSocket.new
client.connect "localhost", 1234
# Send a text message to server
client.send "message"
# Receive text message from client
message, client_addr = server.receive
# Close client and server
client.close
server.close
The send
methods may sporadically fail with Errno::ECONNREFUSED
when sending datagrams
to a non-listening server.
Wrap with an exception handler to prevent raising. Example:
begin
client.send(message, @destination)
rescue ex : Errno
if ex.errno == Errno::ECONNREFUSED
p ex.inspect
end
end
Defined in:
socket/udp_socket.crConstructors
Instance Method Summary
-
#receive(message : Bytes) : Tuple(Int32, IPAddress)
Receives a binary message from the previously bound address.
-
#receive(max_message_size = 512) : Tuple(String, IPAddress)
Receives a text message from the previously bound address.
Instance methods inherited from class IPSocket
local_address
local_address,
remote_address
remote_address
Instance methods inherited from class Socket
accept
accept,
accept?
accept?,
bind(addr, &block)bind(host : String, port : Int)
bind(port : Int)
bind(addr) bind, blocking blocking, blocking=(value) blocking=, broadcast=(val : Bool) broadcast=, broadcast? broadcast?, close_on_exec=(arg : Bool) close_on_exec=, close_on_exec? close_on_exec?, close_read close_read, close_write close_write, closed? : Bool closed?, connect(addr, timeout = nil, &block)
connect(addr, timeout = nil) : Nil
connect(host : String, port : Int, connect_timeout = nil) connect, family : Family family, fcntl(cmd, arg = 0) fcntl, fd : Int32 fd, finalize finalize, getsockopt(optname, optval, level = LibC::SOL_SOCKET) getsockopt, inspect(io) inspect, keepalive=(val : Bool) keepalive=, keepalive? keepalive?, linger linger, linger=(val : Int?) linger=, listen(backlog = SOMAXCONN)
listen(backlog = SOMAXCONN, &block) listen, protocol : Protocol protocol, receive(max_message_size = 512) : Tuple(String, Address)
receive(message : Bytes) : Tuple(Int32, Address) receive, recv_buffer_size recv_buffer_size, recv_buffer_size=(val : Int32) recv_buffer_size=, reuse_address=(val : Bool) reuse_address=, reuse_address? reuse_address?, reuse_port=(val : Bool) reuse_port=, reuse_port? reuse_port?, send(message, to addr : Address)
send(message) send, send_buffer_size send_buffer_size, send_buffer_size=(val : Int32) send_buffer_size=, setsockopt(optname, optval, level = LibC::SOL_SOCKET) setsockopt, tty? tty?, type : Type type
Constructor methods inherited from class Socket
new(fd : Int32, family, type, protocol = Protocol::IP, blocking = false)new(family, type, protocol = Protocol::IP, blocking = false) new
Class methods inherited from class Socket
fcntl(fd, cmd, arg = 0)
fcntl,
ip?(string : String)
ip?,
tcp(family : Family, blocking = false)
tcp,
udp(family : Family, blocking = false)
udp,
unix(type : Type = Type::STREAM, blocking = false)
unix
Instance methods inherited from module IO::Syscall
read_syscall_helper(slice : Bytes, errno_msg : String, &block) : Int32
read_syscall_helper,
read_timeout : Time::Span?
read_timeout,
read_timeout=(read_timeout : Number) : Numberread_timeout=(timeout : Time::Span?) : Time::Span? read_timeout=, write_syscall_helper(slice : Bytes, errno_msg : String, &block) : Nil write_syscall_helper, write_timeout : Time::Span? write_timeout, write_timeout=(write_timeout : Number) : Number
write_timeout=(timeout : Time::Span?) : Time::Span? write_timeout=
Instance methods inherited from module IO::Buffered
close : Nil
close,
flush
flush,
flush_on_newline=(flush_on_newline)
flush_on_newline=,
flush_on_newline?
flush_on_newline?,
peek : Bytes?
peek,
read(slice : Bytes)
read,
rewind
rewind,
sync=(sync)
sync=,
sync?
sync?,
unbuffered_close
unbuffered_close,
unbuffered_flush
unbuffered_flush,
unbuffered_read(slice : Bytes)
unbuffered_read,
unbuffered_rewind
unbuffered_rewind,
unbuffered_write(slice : Bytes)
unbuffered_write,
write(slice : Bytes)
write
Instance methods inherited from class IO
<<(obj) : self
<<,
close
close,
closed?
closed?,
each_byte(&block) : Nileach_byte each_byte, each_char(&block) : Nil
each_char each_char, each_line(*args, **options, &block) : Nil
each_line(*args, **options) each_line, encoding : String encoding, flush flush, gets(delimiter : Char, limit : Int, chomp = false) : String?
gets(delimiter : Char, chomp = false) : String?
gets(chomp = true) : String?
gets(limit : Int, chomp = false) : String?
gets(delimiter : String, chomp = false) : String? gets, gets_to_end : String gets_to_end, peek : Bytes? peek, pos pos, pos=(value) pos=, print(*objects : _) : Nil
print(obj) : Nil print, printf(format_string, *args) : Nil
printf(format_string, args : Array | Tuple) : Nil printf, puts(*objects : _) : Nil
puts : Nil
puts(obj) : Nil
puts(string : String) : Nil puts, read(slice : Bytes) read, read_at(offset, bytesize, &block) read_at, read_byte : UInt8? read_byte, read_bytes(type, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) read_bytes, read_char : Char? read_char, read_fully(slice : Bytes) read_fully, read_fully?(slice : Bytes) read_fully?, read_line(*args, **options) : String read_line, read_string(bytesize : Int) : String read_string, read_utf8(slice : Bytes) read_utf8, read_utf8_byte read_utf8_byte, rewind rewind, seek(offset, whence : Seek = Seek::Set) seek, set_encoding(encoding : String, invalid : Symbol? = nil) set_encoding, skip(bytes_count : Int) : Nil skip, skip_to_end : Nil skip_to_end, tell tell, tty? : Bool tty?, write(slice : Bytes) : Nil write, write_byte(byte : UInt8) write_byte, write_bytes(object, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) write_bytes, write_utf8(slice : Bytes) write_utf8
Class methods inherited from class IO
copy(src, dst, limit : Int)copy(src, dst) copy, pipe(read_blocking = false, write_blocking = false) : Tuple(IO::FileDescriptor, IO::FileDescriptor)
pipe(read_blocking = false, write_blocking = false, &block) pipe
Instance methods inherited from class Reference
==(other : self)==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup, hash(hasher) hash, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference)
same?(other : Nil) same?, to_s(io : IO) : Nil to_s
Constructor methods inherited from class Reference
new
new
Instance methods inherited from class Object
!=(other)
!=,
!~(other)
!~,
==(other)
==,
===(other : JSON::Any)===(other : YAML::Any)
===(other) ===, =~(other) =~, class class, dup dup, hash(hasher)
hash hash, inspect(io : IO)
inspect inspect, itself itself, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, tap(&block) tap, to_json(io : IO)
to_json to_json, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ") to_pretty_json, to_s
to_s(io : IO) to_s, to_yaml(io : IO)
to_yaml to_yaml, try(&block) try, unsafe_as(type : T.class) forall T unsafe_as
Constructor methods inherited from class Object
from_json(string_or_io, root : String) : selffrom_json(string_or_io) : self from_json, from_yaml(string_or_io : String | IO) : self from_yaml
Constructor Detail
Instance Method Detail
Receives a binary message from the previously bound address.
server = UDPSocket.new
server.bind "localhost", 1234
message = Bytes.new(32)
bytes_read, client_addr = server.receive(message)
Receives a text message from the previously bound address.
server = UDPSocket.new
server.bind("localhost", 1234)
message, client_addr = server.receive