UDPSocket

UDPSocket类

Parent:IPSocket

UDPSocket代表一个UDP / IP套接字。

公共类方法

new(address_family) → socket Show source

创建一个新的UDPSocket对象。

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
}

公共实例方法

bind(host, port) #→ 0 Show source

将udpsocket绑定到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
}

connect(host, port) → 0 Show source

Connects udpsocket to host:port.

这使得可以发送没有目的地地址。

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
}

recvfrom_nonblock(maxlen [, flags[, outbuf , options]]) → mesg, sender_inet_addr()

在为基础文件描述符设置O_NONBLOCK后，使用recvfrom（2）从udpsocket接收maxlen字节。标志是零个或多个MSG_选项。结果的第一个元素mesg是收到的数据。第二个元素sender_inet_addr是一个表示发件人地址的数组。

当recvfrom（2）返回0时，Socket＃recvfrom_nonblock返回一个空字符串作为数据。它意味着一个空包。

参数

maxlen - 从套接字接收的字节数

flags- 零个或多个MSG_选项

outbuf - 目标字符串缓冲区

options - 关键字散列，支持 exception: false

例

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

如果调用recvfrom_nonblock失败，可以引发异常，请参考Socket＃recvfrom 。

#recvfrom_nonblock可能引发对应于recvfrom（2）失败的错误，包括Errno :: EWOULDBLOCK。

如果该异常是Errno :: EWOULDBLOCK或Errno :: EAGAIN，则它由IO :: WaitReadable扩展。所以IO :: WaitReadable可以用来解救重试recvfrom_nonblock的异常。

通过指定关键字参数异常来false，你可以指出#recvfrom_nonblock应该不会引发IO :: WaitReadable异常，但返回的符号:wait_readable来代替。

参阅

Socket#recvfrom

# File ext/socket/lib/socket.rb, line 1254
def recvfrom_nonblock(len, flag = 0, outbuf = nil, exception: true)
  __recvfrom_nonblock(len, flag, outbuf, exception)
end

send(mesg, flags, host, port) → numbytes_sent Show source

send(mesg, flags, sockaddr_to) → numbytes_sent

send(mesg, flags) → numbytes_sent

通过udpsocket 发送mesg。

flags 应该是Socket :: MSG_ *常量的按位或。

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;
}