Class Socket provides access to the underlying operating system socket implementations. It can be used to provide more operating system specific functionality than the protocol-specific socket classes but at the expense of greater complexity. In particular, the class handles addresses using +struct sockaddr+ structures packed into Ruby strings, which can be a joy to manipulate.

Exception Handling

Ruby’s implementation of Socket causes an exception to be raised based on the error generated by the system dependent implementation. This is why the methods are documented in a way that isolate Unix-based system exceptions from Windows based exceptions. If more information on particular exception is needed please refer to the Unix manual pages or the Windows WinSock reference.

Documentation by

  • Zach Dennis
  • Sam Roberts
  • Programming Ruby from The Pragmatic Bookshelf.

Much material in this documentation is taken with permission from Programming Ruby from The Pragmatic Bookshelf.

Methods
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Instance Public methods
bind(host, port)
This method is also aliased as original_resolv_bind

Source: show 

    # File lib/resolv-replace.rb, line 25
25:   def bind(host, port)
26:     host = IPSocket.getaddress(host) if host != ""
27:     original_resolv_bind(host, port)
28:   end
connect(host, port)
This method is also aliased as original_resolv_connect

Source: show 

    # File lib/resolv-replace.rb, line 31
31:   def connect(host, port)
32:     original_resolv_connect(IPSocket.getaddress(host), port)
33:   end
original_resolv_bind(host, port)

Alias for bind

original_resolv_connect(host, port)

Alias for connect

original_resolv_send(mesg, flags, *rest)

Alias for send

udpsocket.recvfrom_nonblock(maxlen) => [mesg, sender_inet_addr] udpsocket.recvfrom_nonblock(maxlen, flags) => [mesg, sender_inet_addr]

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#recvfrom_nonblock returns an empty string as data. It means an empty packet.

Parameters

  • maxlen - the number of bytes to receive from the socket
  • flags - zero or more of the MSG_ options

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
     IO.select([s2])
     p s2.recvfrom_nonblock(10)  #=> ["aaa", ["AF_INET", 33302, "localhost.localdomain", "127.0.0.1"]]

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::EAGAIN.

See

Source: show 

static VALUE
udp_recvfrom_nonblock(int argc, VALUE *argv, VALUE sock)
{
    return s_recvfrom_nonblock(sock, argc, argv, RECV_IP);
}
send(mesg, flags, *rest)
This method is also aliased as original_resolv_send

Source: show 

    # File lib/resolv-replace.rb, line 36
36:   def send(mesg, flags, *rest)
37:     if rest.length == 2
38:       host, port = rest
39:       begin
40:         addrs = Resolv.getaddresses(host)
41:       rescue Resolv::ResolvError
42:         raise SocketError, "Hostname not known: #{host}"
43:       end
44:       err = nil
45:       addrs[0...-1].each {|addr|
46:         begin
47:           return original_resolv_send(mesg, flags, addr, port)
48:         rescue SystemCallError
49:         end
50:       }
51:       original_resolv_send(mesg, flags, addrs[-1], port)
52:     else
53:       original_resolv_send(mesg, flags, *rest)
54:     end
55:   end