Class: Async::DNS::Cache

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

Overview

Provides a local in-memory cache for DNS resources.

Defined Under Namespace

Classes: Entry

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Cache

Create a new cache.



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# File 'lib/async/dns/cache.rb', line 25

def initialize
  @store = {}
end

Instance Method Details

#fetch(name, resource_classes) ⇒ Object

Fetch a resource from the cache, or if it is not present, yield to the block to fetch it.



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# File 'lib/async/dns/cache.rb', line 34

def fetch(name, resource_classes)
  now = Async::Clock.now
  
  resource_classes.map do |resource_class|
    key = [name, resource_class]
    
    if entries = @store[key]
      entries.delete_if do |entry|
        !entry.fresh?(now)
      end
    else
      entries = (@store[key] = [])
    end
    
    if entries.empty?
      yield(name, resource_class)
    end
    
    entries
  end.flatten.map(&:resource)
end

#store(name, resource_class, resource) ⇒ Object

Store a resource in the cache.



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# File 'lib/async/dns/cache.rb', line 61

def store(name, resource_class, resource)
  key = [name, resource_class]
  entries = (@store[key] ||= [])
  
  entries << Entry.new(Async::Clock.now, name, resource_class, resource)
end