› Async::DNS › Source › Async › DNS › Cache

`class Cache`

Provides a local in-memory cache for DNS resources.

Definitions

`def initialize`

Create a new cache.

Implementation

def initialize
	@store = {}
end

`def fetch(name, resource_classes)`

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

Signature

parameter　name　String: The name of the resource.
parameter　resource_classes　Array(Class(Resolv::DNS::Resource)): The classes of the resources to fetch.
yields　{|name, resource_class| ...}: The block to fetch the resource, it should call #store to store the resource in the cache.

Implementation

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

`def store(name, resource_class, resource)`

Store a resource in the cache.

Signature

parameter　name　String: The name of the resource.
parameter　resource_class　Class(Resolv::DNS::Resource): The class of the resource.
parameter　resource　Resolv::DNS::Resource: The resource to store.

Implementation

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