Someone help to comment this RUBY code to understand, please require \'socket\'

Question

Someone help to comment this RUBY code to understand, please

require 'socket'

def open_port(host, port)

        sock = Socket.new(:INET, :STREAM)

          raw = Socket.pack_sockaddr_in port, host

          puts "#{port} open." if sock.connect(raw)

          rescue(Errno::ECONNREFUSED)

          rescue(Errno::ETIMEDOUT)

end

def main(host, start_port, end_port)

          until start_port==end_port do

            open_port(host, start_port)

            start_port +=1

          end

end

main ARGV[0], ARGV[1].to_i, ARGV[2].to_i

require 'rubygems'

require 'nokogiri'

require 'open-uri'

page=Nokogiri::HTML(open("https://en.wikipedia.org/wiki/Computer_security"))

parse = page.xpath("//text()").text

re = /(S+s+){0,4}[sS]ecurity(s+S+){0,4}/

# Either security or Security between 0-4 words separated with spaces

count =0;

parse.gsub(re) do |item|

          count +=1

          puts " Match #{count} #{item.to_s} "

end

# globally substitute re. For each item print current item

#.to_s converts to string

require 'json'

require 'pp'

require 'net/http'

url = 'http://api.apixu.com/v1/current.json?key=72758ce44d72440a818195031171902&q=Denver,CO'

uri = URI(url)

response = Net::HTTP.get(uri)

j=JSON.parse(response)

pp j

puts "The temperature in #{j['location']['name']} is #{j['current']['temp_f']} degrees."

Explanation / Answer

require 'socket' #This will include the sockets standard library file.
#sockets are endpoints communication channel, to communicate between same machine or different machine.

def open_port(host, port) #This is like a method/function with host and port argument. In ruby the method should be started with lowercase. Otherwise(Uppercase) it will consider as a constant.

        sock = Socket.new(:INET, :STREAM)   #create new sock object -- (:INET, :STREAM) -- TCP socket. INET - comminucation domain, STREAM - socket type

          raw = Socket.pack_sockaddr_in(port, host) #Packs port and host as an AF_INET/AF_INET6 sockaddr string and store the result to 'raw' variable.

          puts "#{port} open." if sock.connect(raw)   #it print the command with result of socket connection. sock.connect - connect socket.

          rescue(Errno::ECONNREFUSED)   #if any failure occure during socket connection, then it will throw the exception with this message. The target 'raw' was not listening for connections refused the connection request

          rescue(Errno::ETIMEDOUT)       # Throw timeout error

end   #enf function/method of open_port

def main(host, start_port, end_port)   #main function/method with 3 argument of host, start_port and end_port.

          until start_port==end_port do #it's one type of looping method in ruby. This will continue to process untill start_port is equal to end_port.

            open_port(host, start_port)       #call open_port method/function to connect socket, and try to connect socket with several port info.

            start_port +=1               #increase start_port value with one for each and every looping.

          end                           #end until loop

end                                       #end main function/method

main ARGV[0], ARGV[1].to_i, ARGV[2].to_i #fucntion call. call main fucntion with 3 arguments. ARGV[0] - host, ARGV[1].to_i - start_port, ARGV[2].to_i - end_port.

#to_i - it will consider only integer.

require 'rubygems'

require 'nokogiri'

require 'open-uri'

page=Nokogiri::HTML(open("https://en.wikipedia.org/wiki/Computer_security")) #open or load html page

parse = page.xpath("//text()").text #It will parse the text of the xpath element.

re = /(S+s+){0,4}[sS]ecurity(s+S+){0,4}/ # Either security or Security between 0-4 words separated with spaces

count =0; #initialize count value with 0

parse.gsub(re) do |item|   #gsub is one type of regular expression in ruby. It will sreach match and return the pattern based on 're' expression.

          count +=1      #increment the count

          puts " Match #{count} #{item.to_s} "       # print the match count value.

end       #end do loop

# globally substitute re. For each item print current item

#.to_s converts to string

require 'json'

require 'pp'

require 'net/http'    #ruby standard library

url = 'http://api.apixu.com/v1/current.json?key=72758ce44d72440a818195031171902&q=Denver,CO' # assign to url

uri = URI(url)   #load url, URI module providing classes to handle the Uniform Resource Identifiers

response = Net::HTTP.get(uri)   #get HTTP header request and store response

j=JSON.parse(response)   #parse respose with json object

pp j   #Pretty-printer for Ruby objects

puts "The temperature in #{j['location']['name']} is #{j['current']['temp_f']} degrees."   #display the result with parsed JSON objects

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