module Sprockets::Caching

`Caching` is an internal mixin whose public methods are exposed on the `Environment` and `Index` classes.

Protected Instance Methods

cache_asset(path) { || ... } click to toggle source

Cache helper method. Takes a `path` argument which maybe a logical path or fully expanded path. The `&block` is passed for finding and building the asset if its not in cache.

# File lib/sprockets/caching.rb, line 9
def cache_asset(path)
  # If `cache` is not set, return fast
  if cache.nil?
    yield

  # Check cache for `path`
  elsif (asset = Asset.from_hash(self, cache_get_hash(path.to_s))) && asset.fresh?(self)
    asset

   # Otherwise yield block that slowly finds and builds the asset
  elsif asset = yield
    hash = {}
    asset.encode_with(hash)

    # Save the asset to its path
    cache_set_hash(path.to_s, hash)

    # Since path maybe a logical or full pathname, save the
    # asset its its full path too
    if path.to_s != asset.pathname.to_s
      cache_set_hash(asset.pathname.to_s, hash)
    end

    asset
  end
end

Private Instance Methods

cache_get(key) click to toggle source

Low level cache getter for `key`. Checks a number of supported cache interfaces.

# File lib/sprockets/caching.rb, line 59
def cache_get(key)
  # `Cache#get(key)` for Memcache
  if cache.respond_to?(:get)
    cache.get(key)

  # `Cache#[key]` so `Hash` can be used
  elsif cache.respond_to?(:[])
    cache[key]

  # `Cache#read(key)` for `ActiveSupport::Cache` support
  elsif cache.respond_to?(:read)
    cache.read(key)

  else
    nil
  end
end
cache_get_hash(key) click to toggle source
# File lib/sprockets/caching.rb, line 44
def cache_get_hash(key)
  hash = cache_get(expand_cache_key(key))
  if hash.is_a?(Hash) && digest.hexdigest == hash['_version']
    hash
  end
end
cache_set(key, value) click to toggle source

Low level cache setter for `key`. Checks a number of supported cache interfaces.

# File lib/sprockets/caching.rb, line 79
def cache_set(key, value)
  # `Cache#set(key, value)` for Memcache
  if cache.respond_to?(:set)
    cache.set(key, value)

  # `Cache#[key]=value` so `Hash` can be used
  elsif cache.respond_to?(:[]=)
    cache[key] = value

  # `Cache#write(key, value)` for `ActiveSupport::Cache` support
  elsif cache.respond_to?(:write)
    cache.write(key, value)
  end

  value
end
cache_set_hash(key, hash) click to toggle source
# File lib/sprockets/caching.rb, line 51
def cache_set_hash(key, hash)
  hash['_version'] = digest.hexdigest
  cache_set(expand_cache_key(key), hash)
  hash
end
expand_cache_key(key) click to toggle source

Strips `Environment#root` from key to make the key work consisently across different servers. The key is also hashed so it does not exceed 250 characters.

# File lib/sprockets/caching.rb, line 40
def expand_cache_key(key)
  File.join('sprockets', digest_class.hexdigest(key.sub(root, '')))
end