How to get my machine's IP address from Ruby w

问题:

I have searched everywhere but their solution requires some form of IP address. Here are the solutions i have found.

    require 'socket'
#METHOD 1
    ip = IPSocket.getaddress(Socket.gethostname)
    puts ip 

#METHOD 2
    host = Socket.gethostname
    puts host

#METHOD 3(uses Google's address)
    ip = UDPSocket.open {|s| s.connect("64.233.187.99", 1); s.addr.last}
    puts ip

#METHOD 4(uses gateway address)
    def local_ip
      orig, Socket.do_not_reverse_lookup = Socket.do_not_reverse_lookup, true  # turn off reverse DNS resolution temporarily

      UDPSocket.open do |s|
        s.connect '192.168.1.1', 1
        s.addr.last
      end
    ensure
      Socket.do_not_reverse_lookup = orig
    end

    ip=local_ip
    puts ip

All of them require IP address of someone. Is there a solution that does not use someone else's IP address? Preferably, platform independent.

回答1:

Isn't the solution you are looking for just:

require 'socket'

addr_infos = Socket.ip_address_list

Since a machine can have multiple interfaces and multiple IP Addresses, this method returns an array of Addrinfo.

You can fetch the exact IP addresses like this:

addr_infos.each do |addr_info|
  puts addr_info.ip_address
end

P.S. The question is a bit old, but shows up as the first item on Google and it doesn't contain the solution most people are looking for, so I decided to post it.

Hope it helps.

回答2:

require 'socket'
Socket::getaddrinfo(Socket.gethostname,"echo",Socket::AF_INET)[0][3]

quite like method 1, actually

回答3:

This is what I've been using in production for years:

require 'socket'
require 'resolv-replace'
ip = Socket.ip_address_list.detect{|intf| intf.ipv4_private?}
ip.ip_address

Works great; tested on aws and classical hosting

回答4:

As there is no such thing as a default ip-interface to a host (there does not need to be any ip-interface at all actually) all assumptions regarding nameing are vague, do not necessarily hold.

The value returned by gethostname() can be defined independently to any ip-setup, so it does not need to reflect a valid host in terms of a hostname which could be resolved to any ip-address.

From the POSIX system's API's view the only reliabe function to test for the availablily of (ip-)interfaces is the function getifaddrs(), which returns a list of all interfaces along with their parameters.

As it looks as if Ruby's current Socket lib does not provide an interface to it, this (http://rubygems.org/gems/system-getifaddrs) gem based approach does seem to be the only way to go.

回答5:

parse the output of the ip command?

from https://gist.github.com/henriquemenezes/a99f13da957515023e78aea30d6c0a48

gw = `ip route show`[/default.*/][/\d+\.\d+\.\d+\.\d+/]

or parse the output of the ipconfig command: https://stackoverflow.com/a/12632929/32453