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Class: Resolv::Hosts

Relationships & Source Files
Inherits: Object
Defined in: lib/resolv.rb

Overview

Hosts is a hostname resolver that uses the system hosts file.

Class Method Summary

Instance Method Summary

Constructor Details

.new(filename = DefaultFileName) ⇒ Hosts

Creates a new Hosts, using filename for its data source.

[ GitHub ] 

  


# File 'lib/resolv.rb', line 183



def initialize(filename = DefaultFileName)
  @filename = filename
  @mutex = Thread::Mutex.new
  @initialized = nil
end


  







Instance Method Details



  

    #each_address(name, &proc)  
  



  

    

Iterates over all IP addresses for name retrieved from the hosts file.


  



  [ GitHub ]


  

  


# File 'lib/resolv.rb', line 230



def each_address(name, &proc)
  lazy_initialize
  @name2addr[name]&.each(&proc)
end


  








  

    #each_name(address, &proc)  
  



  

    

Iterates over all hostnames for address retrieved from the hosts file.


  



  [ GitHub ]


  

  


# File 'lib/resolv.rb', line 255



def each_name(address, &proc)
  lazy_initialize
  @addr2name[address]&.each(&proc)
end


  








  

    #getaddress(name)  
  



  

    

Gets the IP address of name from the hosts file.


  





  
Raises:





  [ GitHub ]


  

  


# File 'lib/resolv.rb', line 213



def getaddress(name)
  each_address(name) {|address| return address}
  raise ResolvError.new("#{@filename} has no name: #{name}")
end


  








  

    #getaddresses(name)  
  



  

    

Gets all IP addresses for name from the hosts file.


  



  [ GitHub ]


  

  


# File 'lib/resolv.rb', line 221



def getaddresses(name)
  ret = []
  each_address(name) {|address| ret << address}
  return ret
end


  








  

    #getname(address)  
  



  

    

Gets the hostname of address from the hosts file.


  





  
Raises:





  [ GitHub ]


  

  


# File 'lib/resolv.rb', line 238



def getname(address)
  each_name(address) {|name| return name}
  raise ResolvError.new("#{@filename} has no address: #{address}")
end


  








  

    #getnames(address)  
  



  

    

Gets all hostnames for address from the hosts file.


  



  [ GitHub ]


  

  


# File 'lib/resolv.rb', line 246



def getnames(address)
  ret = []
  each_name(address) {|name| ret << name}
  return ret
end


  








  

    #lazy_initialize  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/resolv.rb', line 189



def lazy_initialize # :nodoc:
  @mutex.synchronize {
    unless @initialized
      @name2addr = {}
      @addr2name = {}
      File.open(@filename, 'rb') {|f|
        f.each {|line|
          line.sub!(/#.*/, '')
          addr, *hostnames = line.split(/\s+/)
          next unless addr
          (@addr2name[addr] ||= []).concat(hostnames)
          hostnames.each {|hostname| (@name2addr[hostname] ||= []) << addr}
        }
      }
      @name2addr.each {|name, arr| arr.reverse!}
      @initialized = true
    end
  }
  self
end