module MIME::Types::Cache

Caching of MIME::Types registries is advisable if you will be loading the default registry relatively frequently. With the class methods on MIME::Types::Cache, any MIME::Types registry can be marshaled quickly and easily.

The cache is invalidated on a per-data-version basis; a cache file for version 3.2015.1118 will not be reused with version 3.2015.1201.

Public Class Methods

load (cache_file = nil)

Attempts to load the cache from the file provided as a parameter or in the environment variable RUBY_MIME_TYPES_CACHE. Returns nil if the file does not exist, if the file cannot be loaded, or if the data in the cache version is different than this version.

# File lib/mime/types/cache.rb, line 17
  def load(cache_file = nil)
    cache_file ||= ENV["RUBY_MIME_TYPES_CACHE"]
    return nil unless cache_file && File.exist?(cache_file)

    cache = Marshal.load(File.binread(cache_file))
    if cache.version == MIME::Types::Data::VERSION
      Marshal.load(cache.data)
    else
      MIME::Types.logger.error <<-WARNING.chomp.strip
        Could not load MIME::Types cache: invalid version
      WARNING
      nil
    end
  rescue => e
    MIME::Types.logger.error <<-WARNING.chomp.strip
      Could not load MIME::Types cache: #{e}
    WARNING
    nil
  end

save (types = nil, cache_file = nil)

Attempts to save the types provided to the cache file provided.

If types is not provided or is nil, the cache will contain the current MIME::Types default registry.

If cache_file is not provided or is nil, the cache will be written to the file specified in the environment variable RUBY_MIME_TYPES_CACHE. If there is no cache file specified either directly or through the environment, this method will return nil

# File lib/mime/types/cache.rb, line 46
def save(types = nil, cache_file = nil)
  cache_file ||= ENV["RUBY_MIME_TYPES_CACHE"]
  return nil unless cache_file

  types ||= MIME::Types.send(:__types__)

  File.binwrite(cache_file, Marshal.dump(new(MIME::Types::Data::VERSION, Marshal.dump(types))))
end