class MIME::Types

MIME::Types is a registry of MIME types. It is both a class (created with MIME::Types.new) and a default registry (loaded automatically or through interactions with MIME::Types.[] and MIME::Types.type_for).

The Default mime-types Registry¶ ↑

The default mime-types registry is loaded automatically when the library is required (require 'mime/types'), but it may be lazily loaded (loaded on first use) with the use of the environment variable RUBY_MIME_TYPES_LAZY_LOAD having any value other than false. The initial startup is about 14× faster (~10 ms vs ~140 ms), but the registry will be loaded at some point in the future.

The default mime-types registry can also be loaded from a Marshal cache file specific to the version of MIME::Types being loaded. This will be handled automatically with the use of a file referred to in the environment variable RUBY_MIME_TYPES_CACHE. MIME::Types will attempt to load the registry from this cache file (MIME::Type::Cache.load); if it cannot be loaded (because the file does not exist, there is an error, or the data is for a different version of mime-types), the default registry will be loaded from the normal JSON version and then the cache file will be written to the location indicated by RUBY_MIME_TYPES_CACHE. Cache file loads just over 4½× faster (~30 ms vs ~140 ms). loads.

Notes:

• The loading of the default registry is not atomic; when using a multi-threaded environment, it is recommended that lazy loading is not used and mime-types is loaded as early as possible.

• Cache files should be specified per application in a multiprocess environment and should be initialized during deployment or before forking to minimize the chance that the multiple processes will be trying to write to the same cache file at the same time, or that two applications that are on different versions of mime-types would be thrashing the cache.

• Unless cache files are preinitialized, the application using the mime-types cache file must have read/write permission to the cache file.

Usage¶ ↑

require 'mime/types'

plaintext = MIME::Types['text/plain']
print plaintext.media_type           # => 'text'
print plaintext.sub_type             # => 'plain'

puts plaintext.extensions.join(" ")  # => 'asc txt c cc h hh cpp'

puts plaintext.encoding              # => 8bit
puts plaintext.binary?               # => false
puts plaintext.ascii?                # => true
puts plaintext.obsolete?             # => false
puts plaintext.registered?           # => true
puts plaintext.provisional?          # => false
puts plaintext == 'text/plain'       # => true
puts MIME::Type.simplified('x-appl/x-zip') # => 'appl/zip'

# File lib/mime/types/registry.rb, line 16
def [](type_id, complete: false, registered: false)
  __types__[type_id, complete: complete, registered: registered]
end

# File lib/mime/types/registry.rb, line 41
def add(*types)
  __types__.add(*types)
end

# File lib/mime/types/registry.rb, line 21
def count
  __types__.count
end

# File lib/mime/types/registry.rb, line 26
def each
  if block_given?
    __types__.each { |t| yield t }
  else
    enum_for(:each)
  end
end

# File lib/mime/types/logger.rb, line 16
def logger=(logger) # :nodoc
  @logger =
    if logger.nil?
      NullLogger.new
    else
      logger
    end
end

# File lib/mime/types.rb, line 72
def initialize
  @type_variants = Container.new
  @extension_index = Container.new
end

# File lib/mime/types/registry.rb, line 35
def type_for(filename)
  __types__.type_for(filename)
end

puts "\nMIME::Types['text/plain']"
MIME::Types['text/plain'].each { |t| puts t.to_a.join(", ") }

puts "\nMIME::Types[/^image/, complete: true]"
MIME::Types[/^image/, :complete => true].each do |t|
  puts t.to_a.join(", ")
end

1. Complete definitions sort before incomplete ones;
2. IANA-registered definitions sort before LTSW-recorded
   definitions.
3. Current definitions sort before obsolete ones;
4. Obsolete definitions with use-instead clauses sort before those
   without;
5. Obsolete definitions use-instead clauses are compared.
6. Sort on name.

# File lib/mime/types.rb, line 122
def [](type_id, complete: false, registered: false)
  matches =
    case type_id
    when MIME::Type
      @type_variants[type_id.simplified]
    when Regexp
      match(type_id)
    else
      @type_variants[MIME::Type.simplified(type_id)]
    end

  prune_matches(matches, complete, registered).sort
end

# File lib/mime/types.rb, line 166
def add(*types)
  quiet = (types.last == :silent) || (types.last == true)

  types.each do |mime_type|
    case mime_type
    when true, false, nil, Symbol
      nil
    when MIME::Types
      variants = mime_type.instance_variable_get(:@type_variants)
      add(*variants.values.inject(Set.new, :+).to_a, quiet)
    when Array
      add(*mime_type, quiet)
    else
      add_type(mime_type, quiet)
    end
  end
end

# File lib/mime/types.rb, line 187
  def add_type(type, quiet = false)
    if !quiet && @type_variants[type.simplified].include?(type)
      MIME::Types.logger.debug <<-WARNING.chomp.strip
        Type #{type} is already registered as a variant of #{type.simplified}.
      WARNING
    end

    add_type_variant!(type)
    index_extensions!(type)
  end

# File lib/mime/types.rb, line 78
def count
  @type_variants.values.inject(0) { |a, e| a + e.size }
end

# File lib/mime/types.rb, line 87
def each
  if block_given?
    @type_variants.each_value { |tv| tv.each { |t| yield t } }
  else
    enum_for(:each)
  end
end

puts MIME::Types.type_for('citydesk.xml')
  => [application/xml, text/xml]
puts MIME::Types.type_for('citydesk.gif')
  => [image/gif]
puts MIME::Types.type_for(%w(citydesk.xml citydesk.gif))
  => [application/xml, image/gif, text/xml]

# File lib/mime/types.rb, line 148
def type_for(filename)
  wanted = Array(filename).map { |fn| fn.chomp.downcase[/\.?([^.]*?)\z/m, 1] }

  wanted
    .flat_map { |ext| @extension_index[ext] }
    .compact
    .reduce(Set.new, :+)
    .sort { |a, b|
    a.__extension_priority_compare(b, wanted)
  }
end