class TCPSocket

TCPSocket represents a TCP/IP client socket.

A simple client may look like:

require 'socket'

s = TCPSocket.new 'localhost', 2000

while line = s.gets # Read lines from socket
  puts line         # and print them
end

s.close             # close socket when done

Public Class Methods

gethostbyname(hostname) → [official_hostname, alias_hostnames, address_family, *address_list]

Use Addrinfo.getaddrinfo instead. This method is deprecated for the following reasons:

  • The 3rd element of the result is the address family of the first address. The address families of the rest of the addresses are not returned.

  • gethostbyname() may take a long time and it may block other threads. (GVL cannot be released since gethostbyname() is not thread safe.)

  • This method uses gethostbyname() function already removed from POSIX.

This method lookups host information by hostname.

TCPSocket.gethostbyname("localhost")
#=> ["localhost", ["hal"], 2, "127.0.0.1"]

static VALUE
tcp_s_gethostbyname(VALUE obj, VALUE host)
{
    rb_warn("TCPSocket.gethostbyname is deprecated; use Addrinfo.getaddrinfo instead.");
    struct rb_addrinfo *res =
        rsock_addrinfo(host, Qnil, AF_UNSPEC, SOCK_STREAM, AI_CANONNAME);
    return rsock_make_hostent(host, res, tcp_sockaddr);
}
new(remote_host, remote_port, local_host=nil, local_port=nil, connect_timeout: nil)

Opens a TCP connection to remote_host on remote_port. If local_host and local_port are specified, then those parameters are used on the local end to establish the connection.

:connect_timeout

specify the timeout in seconds.

static VALUE
tcp_init(int argc, VALUE *argv, VALUE sock)
{
    VALUE remote_host, remote_serv;
    VALUE local_host, local_serv;
    VALUE opt;
    static ID keyword_ids[2];
    VALUE kwargs[2];
    VALUE resolv_timeout = Qnil;
    VALUE connect_timeout = Qnil;

    if (!keyword_ids[0]) {
        CONST_ID(keyword_ids[0], "resolv_timeout");
        CONST_ID(keyword_ids[1], "connect_timeout");
    }

    rb_scan_args(argc, argv, "22:", &remote_host, &remote_serv,
                        &local_host, &local_serv, &opt);

    if (!NIL_P(opt)) {
        rb_get_kwargs(opt, keyword_ids, 0, 2, kwargs);
        if (kwargs[0] != Qundef) { resolv_timeout = kwargs[0]; }
        if (kwargs[1] != Qundef) { connect_timeout = kwargs[1]; }
    }

    return rsock_init_inetsock(sock, remote_host, remote_serv,
                               local_host, local_serv, INET_CLIENT,
                               resolv_timeout, connect_timeout);
}