class MIME::Type

The definition of one MIME content-type.

Usage

require "mime/types"

plaintext = MIME::Types["text/plain"] # => [ text/plain ]
text = plaintext.first
puts text.media_type            # => "text"
puts text.sub_type              # => "plain"

puts text.extensions.join(" ")  # => "txt asc c cc h hh cpp hpp dat hlp"
puts text.preferred_extension   # => "txt"
puts text.friendly              # => "Text Document"
puts text.i18n_key              # => "text.plain"

puts text.encoding              # => quoted-printable
puts text.default_encoding      # => quoted-printable
puts text.binary?               # => false
puts text.ascii?                # => true
puts text.obsolete?             # => false
puts text.registered?           # => true
puts text.provisional?          # => false
puts text.complete?             # => true

puts text                       # => "text/plain"

puts text == "text/plain"       # => true
puts "text/plain" == text       # => true
puts text == "text/x-plain"     # => false
puts "text/x-plain" == text     # => false

puts MIME::Type.simplified("x-appl/x-zip") # => "x-appl/x-zip"
puts MIME::Type.i18n_key("x-appl/x-zip") # => "x-appl.x-zip"

puts text.like?("text/x-plain") # => true
puts text.like?(MIME::Type.new("content-type" => "x-text/x-plain")) # => true

puts text.xrefs.inspect # => { "rfc" => [ "rfc2046", "rfc3676", "rfc5147" ] }
puts text.xref_urls # => [ "http://www.iana.org/go/rfc2046",
                    #      "http://www.iana.org/go/rfc3676",
                    #      "http://www.iana.org/go/rfc5147" ]

xtext = MIME::Type.new("x-text/x-plain")
puts xtext.media_type # => "text"
puts xtext.raw_media_type # => "x-text"
puts xtext.sub_type # => "plain"
puts xtext.raw_sub_type # => "x-plain"
puts xtext.complete? # => false

puts MIME::Types.any? { |type| type.content_type == "text/plain" } # => true
puts MIME::Types.all?(&:registered?) # => false

# Various string representations of MIME types
qcelp = MIME::Types["audio/QCELP"].first # => audio/QCELP
puts qcelp.content_type         # => "audio/QCELP"
puts qcelp.simplified           # => "audio/qcelp"

xwingz = MIME::Types["application/x-Wingz"].first # => application/x-Wingz
puts xwingz.content_type        # => "application/x-Wingz"
puts xwingz.simplified          # => "application/x-wingz"

Constants

VERSION

The released version of the mime-types library.

Attributes

content_type[R]

Returns the whole MIME content-type string.

The content type is a presentation value from the MIME type registry and should not be used for comparison. The case of the content type is preserved, and extension markers (x-) are kept.

text/plain        => text/plain
x-chemical/x-pdb  => x-chemical/x-pdb
audio/QCELP       => audio/QCELP
docs[RW]

The documentation for this MIME::Type.

encoding[RW]

The encoding (7bit, 8bit, quoted-printable, or base64) required to transport the data of this content type safely across a network, which roughly corresponds to Content-Transfer-Encoding. A value of nil or :default will reset the encoding to the default_encoding for the MIME::Type. Raises ArgumentError if the encoding provided is invalid.

If the encoding is not provided on construction, this will be either “quoted-printable” (for text/* media types) and “base64” for eveything else.

i18n_key[R]

A key suitable for use as a lookup key for translations, such as with the I18n library.

call-seq:

text_plain.i18n_key # => "text.plain"
3gpp_xml.i18n_key   # => "application.vnd-3gpp-bsf-xml"
  # from application/vnd.3gpp.bsf+xml
x_msword.i18n_key   # => "application.word"
  # from application/x-msword
media_type[R]

Returns the media type of the simplified MIME::Type.

text/plain        => text
x-chemical/x-pdb  => x-chemical
audio/QCELP       => audio
obsolete[R]

Returns true if the media type is obsolete.

:attr_accessor: obsolete

obsolete?[R]

Returns true if the media type is obsolete.

:attr_accessor: obsolete

preferred_extension[RW]

The preferred extension for this MIME type. If one is not set and there are exceptions defined, the first extension will be used.

When setting preferred_extensions, if extensions does not contain this extension, this will be added to extensions.

provisional[R]

Indicates whether the MIME type's registration with IANA is provisional.

:attr_accessor: provisional

raw_media_type[R]

Returns the media type of the unmodified MIME::Type.

text/plain        => text
x-chemical/x-pdb  => x-chemical
audio/QCELP       => audio
raw_sub_type[R]

Returns the media type of the unmodified MIME::Type.

text/plain        => plain
x-chemical/x-pdb  => x-pdb
audio/QCELP       => qcelp
registered[R]

Indicates whether the MIME type has been registered with IANA.

:attr_accessor: registered

registered?[R]

Indicates whether the MIME type has been registered with IANA.

:attr_accessor: registered

signature[RW]

Indicateswhether the MIME type is declared as a signature type.

signature?[RW]

Indicateswhether the MIME type is declared as a signature type.

simplified[R]

A simplified form of the MIME content-type string, suitable for case-insensitive comparison, with the content_type converted to lowercase.

text/plain        => text/plain
x-chemical/x-pdb  => x-chemical/x-pdb
audio/QCELP       => audio/qcelp
sub_type[R]

Returns the sub-type of the simplified MIME::Type.

text/plain        => plain
x-chemical/x-pdb  => pdb
audio/QCELP       => QCELP
use_instead[RW]

Returns the media type or types that should be used instead of this media type, if it is obsolete. If there is no replacement media type, or it is not obsolete, nil will be returned.

xrefs[RW]

The cross-references list for this MIME::Type.

Public Class Methods

i18n_key(content_type) click to toggle source

Converts a provided content_type into a translation key suitable for use with the I18n library.

# File lib/mime/type.rb, line 629
def i18n_key(content_type)
  simplify_matchdata(match(content_type), joiner: ".") { |e|
    e.gsub!(I18N_RE, "-")
  }
end
match(content_type) click to toggle source

Return a MatchData object of the content_type against pattern of media types.

# File lib/mime/type.rb, line 637
def match(content_type)
  case content_type
  when MatchData
    content_type
  else
    MEDIA_TYPE_RE.match(content_type)
  end
end
new(content_type) { |self| ... } click to toggle source

Builds a MIME::Type object from the content_type, a MIME Content Type value (e.g., “text/plain” or “application/x-eruby”). The constructed object is yielded to an optional block for additional configuration, such as associating extensions and encoding information.

There are two deprecated initialization forms:

  • When provided an Array, the MIME::Type will be constructed using the first element as the content type and the remaining flattened elements as extensions.

  • Otherwise, the content_type will be used as a string.

Yields the newly constructed self object.

# File lib/mime/type.rb, line 133
def initialize(content_type) # :yields: self
  @friendly = {}
  @obsolete = @registered = @provisional = false
  @preferred_extension = @docs = @use_instead = @__sort_priority = nil

  self.extensions = []

  case content_type
  when Hash
    init_with(content_type)
  when Array
    MIME::Types.deprecated(
      class: MIME::Type,
      method: :new,
      pre: "when called with an Array",
      once: true
    )
    self.content_type = content_type.shift
    self.extensions = content_type.flatten
  when MIME::Type
    init_with(content_type.to_h)
  else
    MIME::Types.deprecated(
      class: MIME::Type,
      method: :new,
      pre: "when called with a String",
      once: true
    )
    self.content_type = content_type
  end

  self.encoding ||= :default
  self.xrefs ||= {}

  yield self if block_given?

  update_sort_priority
end
simplified(content_type, remove_x_prefix: false) click to toggle source

MIME media types are case-insensitive, but are typically presented in a case-preserving format in the type registry. This method converts content_type to lowercase.

In previous versions of mime-types, this would also remove any extension prefix (x-). This is no longer default behaviour, but may be provided by providing a truth value to remove_x_prefix.

# File lib/mime/type.rb, line 623
def simplified(content_type, remove_x_prefix: false)
  simplify_matchdata(match(content_type), remove_x_prefix)
end

Private Class Methods

simplify_matchdata(matchdata, remove_x = false, joiner: "/") { |e| ... } click to toggle source
# File lib/mime/type.rb, line 648
def simplify_matchdata(matchdata, remove_x = false, joiner: "/")
  return nil unless matchdata

  matchdata.captures.map { |e|
    e.downcase!
    e.sub!(/^x-/, "") if remove_x
    yield e if block_given?
    e
  }.join(joiner)
end

Public Instance Methods

<=>(other) click to toggle source

Compares the other MIME::Type against the exact content type or the simplified type (the simplified type will be used if comparing against something that can be treated as a String with to_s). In comparisons, this is done against the lowercase version of the MIME::Type.

Note that this implementation of #<=> is deprecated and will be changed in the next major version to be the same as priority_compare.

Note that MIME::Types no longer compare against nil.

# File lib/mime/type.rb, line 193
def <=>(other)
  return priority_compare(other) if other.is_a?(MIME::Type)
  simplified <=> other
end
add_extensions(*extensions) click to toggle source

Merge the extensions provided into this MIME::Type. The extensions added will be merged uniquely.

# File lib/mime/type.rb, line 338
def add_extensions(*extensions)
  self.extensions += extensions
end
ascii?() click to toggle source

MIME types can be specified to be sent across a network in particular formats. This method returns false when the MIME::Type encoding is set to base64.

# File lib/mime/type.rb, line 516
def ascii?
  ASCII_ENCODINGS.include?(encoding)
end
binary?() click to toggle source

MIME types can be specified to be sent across a network in particular formats. This method returns true when the MIME::Type encoding is set to base64.

# File lib/mime/type.rb, line 509
def binary?
  BINARY_ENCODINGS.include?(encoding)
end
complete?() click to toggle source

Returns true if the MIME::Type specifies an extension list, indicating that it is a complete MIME::Type.

# File lib/mime/type.rb, line 526
def complete?
  !@extensions.empty?
end
default_encoding() click to toggle source

Returns the default encoding for the MIME::Type based on the media type.

# File lib/mime/type.rb, line 391
def default_encoding
  (@media_type == "text") ? "quoted-printable" : "base64"
end
encode_with(coder) click to toggle source

Populates the coder with attributes about this record for serialization. The structure of coder should match the structure used with init_with.

This method should be considered a private implementation detail.

# File lib/mime/type.rb, line 560
def encode_with(coder)
  coder["content-type"] = @content_type
  coder["docs"] = @docs unless @docs.nil? || @docs.empty?
  coder["friendly"] = @friendly unless @friendly.nil? || @friendly.empty?
  coder["encoding"] = @encoding
  coder["extensions"] = @extensions.to_a unless @extensions.empty?
  coder["preferred-extension"] = @preferred_extension if @preferred_extension
  if obsolete?
    coder["obsolete"] = obsolete?
    coder["use-instead"] = use_instead if use_instead
  end
  unless xrefs.empty?
    {}.tap do |hash|
      xrefs.each do |k, v|
        hash[k] = v.to_a.sort
      end
      coder["xrefs"] = hash
    end
  end
  coder["registered"] = registered?
  coder["provisional"] = provisional? if provisional?
  coder["signature"] = signature? if signature?
  coder["sort-priority"] = __sort_priority || 0b11111111
  coder
end
eql?(other) click to toggle source

Returns true if the other object is a MIME::Type and the content types match.

# File lib/mime/type.rb, line 240
def eql?(other)
  other.is_a?(MIME::Type) && (self == other)
end
extensions() click to toggle source

The list of extensions which are known to be used for this MIME::Type. Non-array values will be coerced into an array with to_a. Array values will be flattened, nil values removed, and made unique.

:attr_accessor: extensions

# File lib/mime/type.rb, line 325
def extensions
  @extensions.to_a
end
friendly # → "Text File" click to toggle source
friendly("en") # → "Text File"

A friendly short description for this MIME::Type.

# File lib/mime/type.rb, line 430
def friendly(lang = "en")
  @friendly ||= {}

  case lang
  when String, Symbol
    @friendly[lang.to_s]
  when Array
    @friendly.update(Hash[*lang])
  when Hash
    @friendly.update(lang)
  else
    fail ArgumentError,
      "Expected a language or translation set, not #{lang.inspect}"
  end
end
hash() click to toggle source

Returns a hash based on the simplified value.

This maintains the invariant that two eql? instances must have the same hash (although having the same hash does not imply that the objects are eql?).

To see why, suppose a MIME::Type instance a is compared to another object b, and that a.eql?(b) is true. By the definition of eql?, we know the following:

  1. b is a MIME::Type instance itself.

  2. a == b is true.

Due to the first point, we know that b should respond to the simplified method. Thus, per the definition of #<=>, we know that a.simplified must be equal to b.simplified, as compared by the <=> method corresponding to a.simplified.

Presumably, if a.simplified <=> b.simplified is 0, then a.simplified has the same hash as b.simplified. So we assume it is suitable for hash to delegate to simplified in service of the eql? invariant.

# File lib/mime/type.rb, line 266
def hash
  simplified.hash
end
init_with(coder) click to toggle source

Initialize an empty object from coder, which must contain the attributes necessary for initializing an empty object.

This method should be considered a private implementation detail.

# File lib/mime/type.rb, line 590
def init_with(coder)
  @__sort_priority = 0
  self.content_type = coder["content-type"]
  self.docs = coder["docs"] || ""
  self.encoding = coder["encoding"]
  self.extensions = coder["extensions"] || []
  self.preferred_extension = coder["preferred-extension"]
  self.obsolete = coder["obsolete"] || false
  self.registered = coder["registered"] || false
  self.provisional = coder["provisional"] || false
  self.signature = coder["signature"]
  self.xrefs = coder["xrefs"] || {}
  self.use_instead = coder["use-instead"]

  friendly(coder["friendly"] || {})

  update_sort_priority
end
like?(other) click to toggle source

Indicates that a MIME type is like another type. This differs from == because x- prefixes are removed for this comparison.

# File lib/mime/type.rb, line 174
def like?(other)
  other =
    if other.respond_to?(:simplified)
      MIME::Type.simplified(other.simplified, remove_x_prefix: true)
    else
      MIME::Type.simplified(other.to_s, remove_x_prefix: true)
    end
  MIME::Type.simplified(simplified, remove_x_prefix: true) == other
end
obsolete=(value) click to toggle source
# File lib/mime/type.rb, line 417
def obsolete=(value)
  clear_sort_priority
  @obsolete = !!value
end
priority_compare(other) click to toggle source

Compares the other MIME::Type using a pre-computed sort priority value, then the simplified representation for an alphabetical sort.

For the next major version of MIME::Types, this method will become #<=> and priority_compare will be removed.

# File lib/mime/type.rb, line 203
def priority_compare(other)
  if (cmp = __sort_priority <=> other.__sort_priority) == 0
    simplified <=> other.simplified
  else
    cmp
  end
end
provisional=(value) click to toggle source
# File lib/mime/type.rb, line 496
def provisional=(value)
  clear_sort_priority
  @provisional = !!value
end
provisional?() click to toggle source

Indicates whether the MIME type's registration with IANA is provisional.

# File lib/mime/type.rb, line 502
def provisional?
  registered? && @provisional
end
registered=(value) click to toggle source
# File lib/mime/type.rb, line 485
def registered=(value)
  clear_sort_priority
  @registered = !!value
end
to_h() click to toggle source

Converts the MIME::Type to a hash. The output of this method can also be used to initialize a MIME::Type.

# File lib/mime/type.rb, line 551
def to_h
  encode_with({})
end
to_json(*args) click to toggle source

Converts the MIME::Type to a JSON string.

# File lib/mime/type.rb, line 544
def to_json(*args)
  require "json"
  to_h.to_json(*args)
end
to_s() click to toggle source

Returns the MIME::Type as a string.

# File lib/mime/type.rb, line 531
def to_s
  content_type
end
to_str() click to toggle source

Returns the MIME::Type as a string for implicit conversions. This allows MIME::Type objects to appear on either side of a comparison.

"text/plain" == MIME::Type.new("content-type" => "text/plain")
# File lib/mime/type.rb, line 539
def to_str
  content_type
end
xref_urls() click to toggle source

The decoded cross-reference URL list for this MIME::Type.

# File lib/mime/type.rb, line 471
def xref_urls
  xrefs.flat_map { |type, values|
    name = :"xref_url_for_#{type.tr("-", "_")}"
    respond_to?(name, true) && xref_map(values, name) || values.to_a
  }
end

Private Instance Methods

clear_sort_priority() click to toggle source
# File lib/mime/type.rb, line 662
def clear_sort_priority
  @__sort_priority = nil
end
content_type=(type_string) click to toggle source
# File lib/mime/type.rb, line 693
def content_type=(type_string)
  match = MEDIA_TYPE_RE.match(type_string)
  fail InvalidContentType, type_string if match.nil?

  @content_type = intern_string(type_string)
  @raw_media_type, @raw_sub_type = match.captures
  @simplified = intern_string(MIME::Type.simplified(match))
  @i18n_key = intern_string(MIME::Type.i18n_key(match))
  @media_type, @sub_type = MEDIA_TYPE_RE.match(@simplified).captures

  @raw_media_type = intern_string(@raw_media_type)
  @raw_sub_type = intern_string(@raw_sub_type)
  @media_type = intern_string(@media_type)
  @sub_type = intern_string(@sub_type)
end
intern_string(string) click to toggle source
# File lib/mime/type.rb, line 710
def intern_string(string)
  -string
end
update_sort_priority() click to toggle source

Update the __sort_priority value. Lower numbers sort better, so the bitmapping may seem a little odd. The best sort priority is 0.

| bit | meaning | details | | — | ————— | ——— | | 7 | obsolete | 1 if true | | 6 | provisional | 1 if true | | 5 | registered | 0 if true | | 4 | complete | 0 if true | | 3 | # of extensions | see below | | 2 | # of extensions | see below | | 1 | # of extensions | see below | | 0 | # of extensions | see below |

The # of extensions is marked as the number of extensions subtracted from 16, to a minimum of 0.

# File lib/mime/type.rb, line 682
def update_sort_priority
  extension_count = @extensions.length
  obsolete = (instance_variable_defined?(:@obsolete) && @obsolete) ? 1 << 7 : 0
  provisional = (instance_variable_defined?(:@provisional) && @provisional) ? 1 << 6 : 0
  registered = (instance_variable_defined?(:@registered) && @registered) ? 0 : 1 << 5
  complete = extension_count.nonzero? ? 0 : 1 << 4
  extension_count = [0, 16 - extension_count].max

  @__sort_priority = obsolete | registered | provisional | complete | extension_count
end
xref_map(values, helper) click to toggle source
# File lib/mime/type.rb, line 721
def xref_map(values, helper)
  values.map { |value| send(helper, value) }
end
xref_url_for_draft(value) click to toggle source
# File lib/mime/type.rb, line 729
def xref_url_for_draft(value)
  "http://www.iana.org/go/%s" % value.sub(/\ARFC/, "draft")
end
xref_url_for_person(value) click to toggle source
# File lib/mime/type.rb, line 737
def xref_url_for_person(value)
  "http://www.iana.org/assignments/media-types/media-types.xhtml#%s" % value
end
xref_url_for_rfc(value) click to toggle source
# File lib/mime/type.rb, line 725
def xref_url_for_rfc(value)
  "http://www.iana.org/go/%s" % value
end
xref_url_for_rfc_errata(value) click to toggle source
# File lib/mime/type.rb, line 733
def xref_url_for_rfc_errata(value)
  "http://www.rfc-editor.org/errata_search.php?eid=%s" % value
end
xref_url_for_template(value) click to toggle source
# File lib/mime/type.rb, line 741
def xref_url_for_template(value)
  "http://www.iana.org/assignments/media-types/%s" % value
end