Class: Async::DNS::System::Hosts

Inherits:
Object
  • Object
show all
Defined in:
lib/async/dns/system.rb

Overview

An interface for querying the system’s hosts file.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Hosts

Create a new hosts file interface.



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# File 'lib/async/dns/system.rb', line 60

def initialize
  @addresses = {}
  @names = {}
end

Class Method Details

.local ⇒ Object

Hosts for the local system.



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# File 'lib/async/dns/system.rb', line 45

def self.local
  hosts = self.new
  
  path = System.hosts_path
  
  if path and File.exist?(path)
    File.open(path) do |file|
      hosts.parse_hosts(file)
    end
  end
  
  return hosts
end

Instance Method Details

#add(address, names) ⇒ Object

Add a new address with the given names.



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# File 'lib/async/dns/system.rb', line 81

def add(address, names)
  @addresses[address] ||= []
  @addresses[address] += names
  
  names.each do |name|
    name = Resolv::DNS::Name.create(name).with_origin(nil)
    
    @names[name] ||= []
    @names[name] << address
  end
end

#each(&block) ⇒ Object 



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# File 'lib/async/dns/system.rb', line 93

def each(&block)
  @names.each(&block)
end

#lookup(name, origin: nil) ⇒ Object Also known as: []

Lookup a name in the hosts file.



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# File 'lib/async/dns/system.rb', line 66

def lookup(name, origin: nil)
  name = Resolv::DNS::Name.create(name).with_origin(origin)
  
  addresses = @names[name]
  
  if addresses
    addresses.last
  else
    nil
  end
end

#parse_hosts(io) ⇒ Object

Parse a hosts file and add the entries.



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# File 'lib/async/dns/system.rb', line 98

def parse_hosts(io)
  io.each do |line|
    line.sub!(/#.*/, "")
    address, hostname, *aliases = line.split(/\s+/)
    
    if address =~ Resolv::IPv4::Regex
      address = Resolv::IPv4.create(address)
    elsif address =~ Resolv::IPv6::Regex
      address = Resolv::IPv6.create(address)
    else
      next
    end
    
    add(address, [hostname] + aliases)
  end
end