module Sprockets::Caching - sprockets-2.11.3 Documentation

# module Sprockets::Caching

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

### Public 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 7
    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_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 27
    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

### 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 48
    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_hash(key) click to toggle source

    # File lib/sprockets/caching.rb, line 83
    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_hash(key, hash) click to toggle source

    # File lib/sprockets/caching.rb, line 90
    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 79
    def expand_cache_key(key)
      File.join('sprockets', digest_class.hexdigest(key.sub(root, '')))
    end