Class: Dnsruby::Cache

Inherits:
Object
  • Object
show all
Defined in:
lib/dnsruby/cache.rb

Overview

:nodoc: all

Defined Under Namespace

Classes: CacheData, CacheKey

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Cache

Returns a new instance of Cache.



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# File 'lib/dnsruby/cache.rb', line 32

def initialize()
@cache = Hash.new
@@max_size = 16*1024 # Get this right...
@mutex = Mutex.new
end

Class Method Details

.delete(qname, qtype, qclass = Classes.IN) ⇒ Object 



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# File 'lib/dnsruby/cache.rb', line 91

def Cache.delete(qname, qtype, qclass = Classes.IN)
  key = CacheKey.new(qname, qtype, qclass)
  @mutex.synchronize {
    @cache.delete(key)
  }
end

.max_size=(length) ⇒ Object 



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# File 'lib/dnsruby/cache.rb', line 48

def Cache.max_size=(length)
   @@max_size = length
end

Instance Method Details

#add(message) ⇒ Object 



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# File 'lib/dnsruby/cache.rb', line 51

def add(message)
  q = message.question[0]
  key = CacheKey.new(q.qname, q.qtype, q.qclass).to_s
  data = CacheData.new(message)
  @mutex.synchronize {
    if (@cache[key])
      TheLog.debug("CACHE REPLACE : #{q.qname}, #{q.qtype}\n")
    else
      TheLog.debug("CACHE ADD : #{q.qname}, #{q.qtype}\n")
    end
    @cache[key] = data

    while @cache.size > @@max_size # keep the cache size reasonable
      @cache.shift
    end
  }
end

#cache ⇒ Object 



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# File 'lib/dnsruby/cache.rb', line 37

def cache
  @cache
end

#clear ⇒ Object 



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# File 'lib/dnsruby/cache.rb', line 40

def clear()
  @mutex.synchronize {
    @cache = Hash.new
  }
end

#find(qname, qtype, qclass = Classes.IN) ⇒ Object

This method “fixes up” the response, so that the header and ttls are OK

The resolver will still need to copy the flags and ID across from the query



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# File 'lib/dnsruby/cache.rb', line 70

def find(qname, qtype, qclass = Classes.IN)
#      print "CACHE find : #{qname}, #{qtype}\n"
  qn = Name.create(qname)
  qn.absolute = true
  key = CacheKey.new(qn, qtype, qclass).to_s
  @mutex.synchronize {
    data = @cache[key]
    if (!data)
#          print "CACHE lookup failed\n"
      return nil
    end
    if (data.expiration <= Time.now.to_i)
      @cache.delete(key)
      TheLog.debug("CACHE lookup stale\n")
      return nil
    end
    m = data.message
    TheLog.debug("CACHE found\n")
    return m
  }
end

#length ⇒ Object 



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# File 'lib/dnsruby/cache.rb', line 45

def length
  return @cache.length
end