Module: Async::DNS::System

Defined in:
lib/async/dns/system.rb

Overview

This module encapsulates system dependent name lookup functionality.

Defined Under Namespace

Classes: Hosts

Constant Summary collapse

RESOLV_CONF = 
"/etc/resolv.conf"
HOSTS = 
"/etc/hosts"

Class Method Summary collapse

Class Method Details

.hosts_path ⇒ Object 



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# File 'lib/async/dns/system.rb', line 33

def self.hosts_path
	if RUBY_PLATFORM =~ /mswin32|mingw|bccwin/
		Win32::Resolv.get_hosts_path
	else
		HOSTS
	end
end

.nameservers ⇒ Object

Get a list of standard nameserver connections which can be used for querying any standard servers that the system has been configured with. There is no equivalent facility to use the ‘hosts` file at present.



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# File 'lib/async/dns/system.rb', line 134

def self.nameservers
	nameservers = []

	if File.exist? RESOLV_CONF
		nameservers = parse_resolv_configuration(RESOLV_CONF)
	elsif defined?(Win32::Resolv) and RUBY_PLATFORM =~ /mswin32|cygwin|mingw|bccwin/
		search, nameservers = Win32::Resolv.get_resolv_info
	end

	return standard_connections(nameservers)
end

.parse_resolv_configuration(path) ⇒ Object 



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# File 'lib/async/dns/system.rb', line 102

def self.parse_resolv_configuration(path)
	nameservers = []
	File.open(path) do |file|
		file.each do |line|
			# Remove any comments:
			line.sub!(/[#;].*/, '')

			# Extract resolv.conf command:
			keyword, *args = line.split(/\s+/)

			case keyword
			when 'nameserver'
				nameservers += args
			end
		end
	end

	return nameservers
end

.standard_connections(nameservers) ⇒ Object 



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# File 'lib/async/dns/system.rb', line 122

def self.standard_connections(nameservers)
	connections = []

	nameservers.each do |host|
		connections << [:udp, host, 53]
		connections << [:tcp, host, 53]
	end

	return connections
end