Class: DNSOMatic::IPLookup

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/dnsomatic/iplookup.rb

Overview

Any callers wishing to use IPStatus objects should request them via an instance of IPLookup. IPLookup is a singleton object that will cache IPStatus objects across sessions by persisting them to a YAML file.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ IPLookup

Because we’re a singleton, we don’t take any initialization arguments.



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# File 'lib/dnsomatic/iplookup.rb', line 96

def initialize
  fn = 'dnsomatic-' + Process.uid.to_s + '.cache'
  @cache_file = File.join(ENV['TEMP'] || '/tmp', fn)

  @cache = Hash.new
  @persist = true
end

Instance Attribute Details

#persist ⇒ Object

Allow a caller to toggle the cache on and off.



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# File 'lib/dnsomatic/iplookup.rb', line 93

def persist
  @persist
end

Instance Method Details

#ip_from_url(url) ⇒ Object

This is the method a caller would use to request and IPStatus object. The url is passed to new() when the object is created or returned from the cache.



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# File 'lib/dnsomatic/iplookup.rb', line 118

def ip_from_url(url)
  load()
  #implement a simple cache to prevent making multiple http requests
  #to the same remote agent (in the case where a user defines multiple
  #updater stanzas that use the same ip fetch url).
  #because an access for a key that doesn't exist returns and inserts
  #a new IPStatus object, we don't differntiate between seen and unseen
  #here.
  if @cache[url]
    @cache[url].update
  else
    @cache[url] = IPStatus.new(url)
  end

  save()  #ensure that we get spooled to disk.
  @cache[url]
end

#setcachefile(file) ⇒ Object

This allows callers to alter which file we will persist our cache of IPStatus objects to.



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# File 'lib/dnsomatic/iplookup.rb', line 106

def setcachefile(file)
  if !File.writable?(File.dirname(file))
    raise(DNSOMatic::Error, "Unwritable cache file directory.")
  elsif File.exists?(file) and !File.writable(file)
    raise(DNSOMatic::Error, "Unwritable cache file")
  end
  @cache_file = file
end