method

udp_server_sockets

Ruby latest stable (v2_5_5) - 0 notes - Class: Socket

udp_server_sockets(host=nil, port) public

Creates UDP/IP sockets for a UDP server.

If no block given, it returns an array of sockets.

If a block is given, the block is called with the sockets. The value of the block is returned. The sockets are closed when this method returns.

If port is zero, some port is chosen. But the chosen port is used for the all sockets.

# UDP/IP echo server
Socket.udp_server_sockets(0) {|sockets|
  p sockets.first.local_address.ip_port     #=> 32963
  Socket.udp_server_loop_on(sockets) {|msg, msg_src|
    msg_src.reply msg
  }
}

Show source

# File ext/socket/lib/socket.rb, line 883
  def self.udp_server_sockets(host=nil, port)
    last_error = nil
    sockets = []

    ipv6_recvpktinfo = nil
    if defined? Socket::AncillaryData
      if defined? Socket::IPV6_RECVPKTINFO # RFC 3542
        ipv6_recvpktinfo = Socket::IPV6_RECVPKTINFO
      elsif defined? Socket::IPV6_PKTINFO # RFC 2292
        ipv6_recvpktinfo = Socket::IPV6_PKTINFO
      end
    end

    local_addrs = Socket.ip_address_list

    ip_list = []
    Addrinfo.foreach(host, port, nil, :DGRAM, nil, Socket::AI_PASSIVE) {|ai|
      if ai.ipv4? && ai.ip_address == "0.0.0.0"
        local_addrs.each {|a|
          next unless a.ipv4?
          ip_list << Addrinfo.new(a.to_sockaddr, :INET, :DGRAM, 0);
        }
      elsif ai.ipv6? && ai.ip_address == "::" && !ipv6_recvpktinfo
        local_addrs.each {|a|
          next unless a.ipv6?
          ip_list << Addrinfo.new(a.to_sockaddr, :INET6, :DGRAM, 0);
        }
      else
        ip_list << ai
      end
    }
    ip_list.uniq!(&:to_sockaddr)

    if port == 0
      sockets = ip_sockets_port0(ip_list, false)
    else
      ip_list.each {|ip|
        ai = Addrinfo.udp(ip.ip_address, port)
        begin
          s = ai.bind
        rescue SystemCallError
          last_error = $!
          next
        end
        sockets << s
      }
      if sockets.empty?
        raise last_error
      end
    end

    sockets.each {|s|
      ai = s.local_address
      if ipv6_recvpktinfo && ai.ipv6? && ai.ip_address == "::"
        s.setsockopt(:IPV6, ipv6_recvpktinfo, 1)
      end
    }

    if block_given?
      begin
        yield sockets
      ensure
        sockets.each(&:close) if sockets
      end
    else
      sockets
    end
  end

udp_server_sockets

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