CODEWITHSUNDEEP
ruby-on-railsrubyruby-on-rails-4
DRD
DRD

Reputation: 131

How to parse string for IP address

I have a database table that contains MAC addresses. Currently I am doing this:

 <% @devices.each do |device| %>
      <tr>
        <td><%= device.mac_address %></td>
      </tr>
  <% end %>

And I have two variables called data that contains a string:

Host is up (0.00s latency). MAC Address: 00:95:7F:A9:A3:81 (Unknown) Nmap scan report for 192.168.1.3 Host is up (0.0020s latency). MAC Address: 00:66:19:38:2E:7E (Unknown) Nmap scan report for 192.168.1.4 
Host is up (0.0030s latency). MAC Address: 00:66:19:38:2F:00 (Unknown) 
Nmap scan report for 192.168.1.5

As I am looping over the MAC addresses, how can I parse data to find the IP following the Mac address? If the current MAC address in the loop is 00:95:7F:A9:A3:81 I need to output 192.168.1.3 as the IP.

Upvotes: 0

Views: 487

Answers (2)

the Tin Man
the Tin Man

Reputation: 160631

Meditate on this:

MAC_ADDRESSES = %w[
  00:95:7F:A9:A3:81
  00:66:19:38:2E:7E
  00:66:19:38:2F:00
]

IP_REGEX = /(?:\d{1,3}\.){3}\d{1,3}/

RESULT = 'Host is up (0.00s latency). MAC Address: 00:95:7F:A9:A3:81 (Unknown) Nmap scan report for 192.168.1.3 Host is up (0.0020s latency). MAC Address: 00:66:19:38:2E:7E (Unknown) Nmap scan report for 192.168.1.4 Host is up (0.0030s latency). MAC Address: 00:66:19:38:2F:00 (Unknown) Nmap scan report for 192.168.1.5'

pairs = MAC_ADDRESSES.map { |mac|
  [mac, RESULT[/#{mac}.+?(#{IP_REGEX})/, 1]]
}.to_h

pairs 
# => {"00:95:7F:A9:A3:81"=>"192.168.1.3",
#     "00:66:19:38:2E:7E"=>"192.168.1.4",
#     "00:66:19:38:2F:00"=>"192.168.1.5"}

pairs['00:66:19:38:2E:7E'] # => "192.168.1.4"

Upvotes: 1

Aleksey Gureiev
Aleksey Gureiev

Reputation: 1759

I'd use Regex here:

macs.each do |mac|
  if @result =~ /#{mac.mac_address}.*?for (\d+\.\d+\.\d+\.\d+)/
    ip = $1
    puts "#{mac} - #{ip}"
  end
end

Upvotes: 0

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