class UDPSocket
UDPSocket
represents a UDP/IP socket.
Public Class Methods
Creates a new UDPSocket
object.
address_family should be an integer, a string or a symbol: Socket::AF_INET, “AF_INET”, :INET, etc.
require 'socket' UDPSocket.new #=> #<UDPSocket:fd 3> UDPSocket.new(Socket::AF_INET6) #=> #<UDPSocket:fd 4>
static VALUE udp_init(int argc, VALUE *argv, VALUE sock) { VALUE arg; int family = AF_INET; int fd; if (rb_scan_args(argc, argv, "01", &arg) == 1) { family = rsock_family_arg(arg); } fd = rsock_socket(family, SOCK_DGRAM, 0); if (fd < 0) { rb_sys_fail("socket(2) - udp"); } return rsock_init_sock(sock, fd); }
Public Instance Methods
Binds udpsocket to host:port.
u1 = UDPSocket.new u1.bind("127.0.0.1", 4913) u1.send "message-to-self", 0, "127.0.0.1", 4913 p u1.recvfrom(10) #=> ["message-to", ["AF_INET", 4913, "localhost", "127.0.0.1"]]
static VALUE udp_bind(VALUE sock, VALUE host, VALUE port) { struct udp_arg arg; VALUE ret; GetOpenFile(sock, arg.fptr); arg.res = rsock_addrinfo(host, port, rsock_fd_family(arg.fptr->fd), SOCK_DGRAM, 0); ret = rb_ensure(udp_bind_internal, (VALUE)&arg, rsock_freeaddrinfo, (VALUE)arg.res); if (!ret) rsock_sys_fail_host_port("bind(2)", host, port); return INT2FIX(0); }
Connects udpsocket to host:port.
This makes possible to send without destination address.
u1 = UDPSocket.new u1.bind("127.0.0.1", 4913) u2 = UDPSocket.new u2.connect("127.0.0.1", 4913) u2.send "uuuu", 0 p u1.recvfrom(10) #=> ["uuuu", ["AF_INET", 33230, "localhost", "127.0.0.1"]]
static VALUE udp_connect(VALUE sock, VALUE host, VALUE port) { struct udp_arg arg; VALUE ret; GetOpenFile(sock, arg.fptr); arg.res = rsock_addrinfo(host, port, rsock_fd_family(arg.fptr->fd), SOCK_DGRAM, 0); ret = rb_ensure(udp_connect_internal, (VALUE)&arg, rsock_freeaddrinfo, (VALUE)arg.res); if (!ret) rsock_sys_fail_host_port("connect(2)", host, port); return INT2FIX(0); }
Receives up to maxlen bytes from udpsocket
using recvfrom(2) after O_NONBLOCK is set for the underlying file descriptor. flags is zero or more of the MSG_
options. The first element of the results, mesg, is the data received. The second element, sender_inet_addr, is an array to represent the sender address.
When recvfrom(2) returns 0, Socket#recv_nonblock
returns nil. In most cases it means the connection was closed, but it may also mean an empty packet was received, as the underlying API makes it impossible to distinguish these two cases.
Parameters¶ ↑
-
maxlen
- the number of bytes to receive from the socket -
flags
- zero or more of theMSG_
options -
outbuf
- destination String buffer -
options
- keyword hash, supporting ‘exception: false`
Example¶ ↑
require 'socket' s1 = UDPSocket.new s1.bind("127.0.0.1", 0) s2 = UDPSocket.new s2.bind("127.0.0.1", 0) s2.connect(*s1.addr.values_at(3,1)) s1.connect(*s2.addr.values_at(3,1)) s1.send "aaa", 0 begin # emulate blocking recvfrom p s2.recvfrom_nonblock(10) #=> ["aaa", ["AF_INET", 33302, "localhost.localdomain", "127.0.0.1"]] rescue IO::WaitReadable IO.select([s2]) retry end
Refer to Socket#recvfrom
for the exceptions that may be thrown if the call to recvfrom_nonblock fails.
UDPSocket#recvfrom_nonblock
may raise any error corresponding to recvfrom(2) failure, including Errno::EWOULDBLOCK.
If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying recvfrom_nonblock.
By specifying a keyword argument exception to false
, you can indicate that recvfrom_nonblock
should not raise an IO::WaitReadable exception, but return the symbol :wait_readable
instead.
See¶ ↑
# File socket/lib/socket.rb, line 1277 def recvfrom_nonblock(len, flag = 0, outbuf = nil, exception: true) __recvfrom_nonblock(len, flag, outbuf, exception) end
Sends mesg via udpsocket.
flags should be a bitwise OR of Socket::MSG_* constants.
u1 = UDPSocket.new u1.bind("127.0.0.1", 4913) u2 = UDPSocket.new u2.send "hi", 0, "127.0.0.1", 4913 mesg, addr = u1.recvfrom(10) u1.send mesg, 0, addr[3], addr[1] p u2.recv(100) #=> "hi"
static VALUE udp_send(int argc, VALUE *argv, VALUE sock) { VALUE flags, host, port; struct udp_send_arg arg; VALUE ret; if (argc == 2 || argc == 3) { return rsock_bsock_send(argc, argv, sock); } rb_scan_args(argc, argv, "4", &arg.sarg.mesg, &flags, &host, &port); StringValue(arg.sarg.mesg); GetOpenFile(sock, arg.fptr); arg.sarg.fd = arg.fptr->fd; arg.sarg.flags = NUM2INT(flags); arg.res = rsock_addrinfo(host, port, rsock_fd_family(arg.fptr->fd), SOCK_DGRAM, 0); ret = rb_ensure(udp_send_internal, (VALUE)&arg, rsock_freeaddrinfo, (VALUE)arg.res); if (!ret) rsock_sys_fail_host_port("sendto(2)", host, port); return ret; }