Class: MIME::Type

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
lib/mime/type.rb

Overview

The definition of one MIME content-type.

Usage

require 'mime/types'

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

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

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

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

Direct Known Subclasses

Columnar

Defined Under Namespace

Classes: Columnar, InvalidContentType, InvalidEncoding

Constant Summary collapse

VERSION =

The released version of the mime-types library.

'2.6.2'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(content_type) {|_self| ... } ⇒ Type

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

  • When provided a Hash or a MIME::Type, the MIME::Type will be constructed with #init_with.

  • When provided an Array, the MIME::Type will be constructed only using the first two elements of the array as the content type and extensions.

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

Yields the newly constructed self object.

Yields:

  • (_self)

Yield Parameters:

  • _self (MIME::Type)

    the object that the method was called on


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# File 'lib/mime/type.rb', line 97

def initialize(content_type) # :yields self:
  @friendly = {}
  self.system = nil
  self.obsolete = false
  self.registered = nil
  self.use_instead = nil
  self.signature = nil

  case content_type
  when Hash
    init_with(content_type)
  when Array
    self.content_type = content_type[0]
    self.extensions = content_type[1] || []
  when MIME::Type
    init_with(content_type.to_h)
  else
    self.content_type = content_type
  end

  self.extensions ||= []
  self.docs ||= []
  self.encoding ||= :default
  # This value will be deprecated in the future, as it will be an
  # alternative view on #xrefs. Silence an unnecessary warning for now by
  # assigning directly to the instance variable.
  @references ||= []
  self.xrefs ||= {}

  yield self if block_given?
end

Instance Attribute Details

#content_typeObject

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

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# File 'lib/mime/type.rb', line 209

def content_type
  @content_type
end

#docsObject

The documentation for this MIME::Type.


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# File 'lib/mime/type.rb', line 340

def docs
  @docs
end

#encodingObject

Returns the value of attribute encoding


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# File 'lib/mime/type.rb', line 280

def encoding
  @encoding
end

#extensionsObject

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.


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# File 'lib/mime/type.rb', line 242

def extensions
  @extensions
end

#i18n_keyObject (readonly)

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

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# File 'lib/mime/type.rb', line 371

def i18n_key
  @i18n_key
end

#media_typeObject (readonly)

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

text/plain        => text
x-chemical/x-pdb  => chemical

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# File 'lib/mime/type.rb', line 222

def media_type
  @media_type
end

#raw_media_typeObject (readonly)

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

text/plain        => text
x-chemical/x-pdb  => x-chemical

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# File 'lib/mime/type.rb', line 227

def raw_media_type
  @raw_media_type
end

#raw_sub_typeObject (readonly)

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

text/plain        => plain
x-chemical/x-pdb  => x-pdb

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# File 'lib/mime/type.rb', line 237

def raw_sub_type
  @raw_sub_type
end

#simplifiedObject (readonly)

A simplified form of the MIME content-type string, suitable for case-insensitive comparison, with any extension markers (<tt>x-</tt) removed and converted to lowercase.

text/plain        => text/plain
x-chemical/x-pdb  => chemical/pdb
audio/QCELP       => audio/qcelp

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# File 'lib/mime/type.rb', line 217

def simplified
  @simplified
end

#sub_typeObject (readonly)

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

text/plain        => plain
x-chemical/x-pdb  => pdb

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# File 'lib/mime/type.rb', line 232

def sub_type
  @sub_type
end

#use_insteadObject


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# File 'lib/mime/type.rb', line 322

def use_instead
  return nil unless obsolete?
  @use_instead
end

#xrefsObject

Returns the value of attribute xrefs


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# File 'lib/mime/type.rb', line 423

def xrefs
  @xrefs
end

Class Method Details

.from_array(*args) ⇒ Object

Creates a MIME::Type from an args array in the form of:

[ type-name, [ extensions ], encoding, system ]

extensions, encoding, and system are optional.

MIME::Type.from_array('application/x-ruby', %w(rb), '8bit')
MIME::Type.from_array([ 'application/x-ruby', [ 'rb' ], '8bit' ])

These are equivalent to:

MIME::Type.new('application/x-ruby') do |t|
  t.extensions  = %w(rb)
  t.encoding    = '8bit'
end

It will yield the type (t) if a block is given.

This method is deprecated and will be removed in mime-types 3.


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# File 'lib/mime/type.rb', line 734

def from_array(*args) # :yields t:
  MIME::Types.deprecated(self, __method__)

  # Dereferences the array one level, if necessary.
  args = args.first if args.first.kind_of? Array

  unless args.size.between?(1, 8)
    fail ArgumentError,
         'Array provided must contain between one and eight elements.'
  end

  MIME::Type.new(args.shift) do |t|
    t.extensions, t.encoding, t.system, t.obsolete, t.docs, t.references,
      t.registered = *args
    yield t if block_given?
  end
end

.from_hash(hash) ⇒ Object

Creates a MIME::Type from a hash. Keys are case-insensitive, dashes may be replaced with underscores, and the internal Symbol of the lowercase-underscore version can be used as well. That is, Content-Type can be provided as content-type, Content_Type, content_type, or :content_type.

Known keys are Content-Type, Content-Transfer-Encoding, Extensions, and System.

MIME::Type.from_hash('Content-Type' => 'text/x-yaml',
                     'Content-Transfer-Encoding' => '8bit',
                     'System' => 'linux',
                     'Extensions' => ['yaml', 'yml'])

This is equivalent to:

MIME::Type.new('text/x-yaml') do |t|
  t.encoding    = '8bit'
  t.system      = 'linux'
  t.extensions  = ['yaml', 'yml']
end

It will yield the constructed type t if a block has been provided.

This method is deprecated and will be removed in mime-types 3.


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# File 'lib/mime/type.rb', line 779

def from_hash(hash) # :yields t:
  MIME::Types.deprecated(self, __method__)
  type = {}
  hash.each_pair do |k, v|
    type[k.to_s.tr('A-Z', 'a-z').gsub(/-/, '_').to_sym] = v
  end

  MIME::Type.new(type[:content_type]) do |t|
    t.extensions  = type[:extensions]
    t.encoding    = type[:content_transfer_encoding]
    t.system      = type[:system]
    t.obsolete    = type[:obsolete]
    t.docs        = type[:docs]
    t.url         = type[:url]
    t.registered  = type[:registered]

    yield t if block_given?
  end
end

.from_mime_type(mime_type) ⇒ Object

Essentially a copy constructor for mime_type.

MIME::Type.from_mime_type(plaintext)

is equivalent to:

MIME::Type.new(plaintext.content_type.dup) do |t|
  t.extensions  = plaintext.extensions.dup
  t.system      = plaintext.system.dup
  t.encoding    = plaintext.encoding.dup
end

It will yield the type (t) if a block is given.

This method is deprecated and will be removed in mime-types 3.


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# File 'lib/mime/type.rb', line 814

def from_mime_type(mime_type) # :yields the new MIME::Type:
  MIME::Types.deprecated(self, __method__)
  new(mime_type)
end

.i18n_key(content_type) ⇒ Object

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


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# File 'lib/mime/type.rb', line 698

def i18n_key(content_type)
  matchdata = case content_type
              when MatchData
                content_type
              else
                MEDIA_TYPE_RE.match(content_type)
              end

  return unless matchdata

  matchdata.captures.map { |e|
    e.downcase!
    e.gsub!(UNREGISTERED_RE, ''.freeze)
    e.gsub!(I18N_RE, '-'.freeze)
    e
  }.join('.'.freeze)
end

.simplified(content_type) ⇒ Object

The MIME types main- and sub-label can both start with x-, which indicates that it is a non-registered name. Of course, after registration this flag may disappear, adds to the confusing proliferation of MIME types. The simplified content_type string has the x- removed and is translated to lowercase.


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# File 'lib/mime/type.rb', line 679

def simplified(content_type)
  matchdata = case content_type
              when MatchData
                content_type
              else
                MEDIA_TYPE_RE.match(content_type)
              end

  return unless matchdata

  matchdata.captures.map { |e|
    e.downcase!
    e.gsub!(UNREGISTERED_RE, ''.freeze)
    e
  }.join('/'.freeze)
end

Instance Method Details

#<=>(other) ⇒ Object

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.


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# File 'lib/mime/type.rb', line 142

def <=>(other)
  if other.respond_to?(:content_type)
    @content_type.downcase <=> other.content_type.downcase
  elsif other.respond_to?(:to_s)
    @simplified <=> MIME::Type.simplified(other.to_s)
  end
end

#add_extensions(*extensions) ⇒ Object

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


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# File 'lib/mime/type.rb', line 251

def add_extensions(*extensions)
  self.extensions = self.extensions + extensions
end

#ascii?Boolean

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.


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# File 'lib/mime/type.rb', line 539

def ascii?
  !binary?
end

#binary?Boolean

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.


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# File 'lib/mime/type.rb', line 532

def binary?
  BINARY_ENCODINGS.include?(@encoding)
end

#complete?Boolean

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


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# File 'lib/mime/type.rb', line 572

def complete?
  !@extensions.empty?
end

#default_encodingObject

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


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# File 'lib/mime/type.rb', line 310

def default_encoding
  (@media_type == 'text') ? 'quoted-printable' : 'base64'
end

#encode_with(coder) ⇒ Object

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.


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# File 'lib/mime/type.rb', line 633

def encode_with(coder)
  coder['content-type']   = @content_type
  coder['docs']           = @docs unless @docs.nil? or @docs.empty?
  coder['friendly']       = @friendly unless @friendly.empty?
  coder['encoding']       = @encoding
  coder['extensions']     = @extensions unless @extensions.empty?
  if obsolete?
    coder['obsolete']     = obsolete?
    coder['use-instead']  = use_instead if use_instead
  end
  coder['references']     = references(true) unless references(true).empty?
  coder['xrefs']          = xrefs unless xrefs.empty?
  coder['registered']     = registered?
  coder['signature']      = signature? if signature?
  coder['system']         = @system if @system
  coder
end

#eql?(other) ⇒ Boolean

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


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# File 'lib/mime/type.rb', line 196

def eql?(other)
  other.kind_of?(MIME::Type) and self == other
end

#friendly(lang = 'en'.freeze) ⇒ Object

A friendly short description for this MIME::Type.

call-seq:

text_plain.friendly         # => "Text File"
text_plain.friendly('en')   # => "Text File"

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# File 'lib/mime/type.rb', line 347

def friendly(lang = 'en'.freeze)
  @friendly ||= {}

  case lang
  when String
    @friendly[lang]
  when Array
    @friendly.merge!(Hash[*lang])
  when Hash
    @friendly.merge!(lang)
  else
    fail ArgumentError
  end
end

#init_with(coder) ⇒ Object

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.


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# File 'lib/mime/type.rb', line 655

def init_with(coder)
  self.content_type = coder['content-type']
  self.docs         = coder['docs'] || []
  friendly(coder['friendly'] || {})
  self.encoding     = coder['encoding']
  self.extensions   = coder['extensions'] || []
  self.obsolete     = coder['obsolete']
  # This value will be deprecated in the future, as it will be an
  # alternative view on #xrefs. Silence an unnecessary warning for now by
  # assigning directly to the instance variable.
  @references       = Array(coder['references']).flatten.compact.uniq
  self.registered   = coder['registered']
  self.signature    = coder['signature']
  self.system       = coder['system']
  self.xrefs        = coder['xrefs'] || {}
  self.use_instead  = coder['use-instead']
end

#like?(other) ⇒ Boolean

Returns true if the other simplified type matches the current type.


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# File 'lib/mime/type.rb', line 130

def like?(other)
  if other.respond_to?(:simplified)
    @simplified == other.simplified
  else
    @simplified == MIME::Type.simplified(other)
  end
end

#obsolete=(v) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 335

def obsolete=(v) # :nodoc:
  @obsolete = !!v
end

#obsolete?Boolean

Returns true if the media type is obsolete.


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# File 'lib/mime/type.rb', line 331

def obsolete?
  !!@obsolete
end

#platform?(__internal__ = false) ⇒ Boolean

Returns true if the MIME::Type is specific to the current operating system as represented by RUBY_PLATFORM.

This method is deprecated and will be removed in mime-types 3.


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# File 'lib/mime/type.rb', line 565

def platform?(__internal__ = false)
  MIME::Types.deprecated(self, __method__) unless __internal__
  system?(__internal__) and (RUBY_PLATFORM =~ @system)
end

#preferred_extensionObject


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# File 'lib/mime/type.rb', line 261

def preferred_extension
  extensions.first
end

#priority_compare(other) ⇒ Object

Compares the other MIME::Type based on how reliable it is before doing a normal <=> comparison. Used by MIME::Types#[] to sort types. The comparisons involved are:

  1. self.simplified <=> other.simplified (ensures that we don't try to compare different types)

  2. IANA-registered definitions < other definitions.

  3. Generic definitions < platform definitions.

  4. Complete definitions < incomplete definitions.

  5. Current definitions < obsolete definitions.

  6. Obselete with use-instead references < obsolete without.

  7. Obsolete use-instead definitions are compared.

While this method is public, its use is strongly discouraged by consumers of mime-types. In mime-types 3, this method is likely to see substantial revision and simplification to ensure current registered content types sort before unregistered or obsolete content types.


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# File 'lib/mime/type.rb', line 167

def priority_compare(other)
  pc = simplified <=> other.simplified
  if pc.zero?
    pc = if (reg = registered?) != other.registered?
           reg ? -1 : 1 # registered < unregistered
         elsif (plat = platform?(true)) != other.platform?(true)
           plat ? 1 : -1 # generic < platform
         elsif (comp = complete?) != other.complete?
           comp ? -1 : 1 # complete < incomplete
         elsif (obs = obsolete?) != other.obsolete?
           obs ? 1 : -1 # current < obsolete
         elsif obs and ((ui = use_instead) != (oui = other.use_instead))
           if ui.nil?
             1
           elsif oui.nil?
             -1
           else
             ui <=> oui
           end
         else
           0
         end
  end

  pc
end

#references(__internal__ = false) ⇒ Object


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# File 'lib/mime/type.rb', line 385

def references(__internal__ = false)
  MIME::Types.deprecated(self, __method__) unless __internal__
  @references
end

#references=(r) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 391

def references=(r) # :nodoc:
  MIME::Types.deprecated(self, __method__)
  @references = Array(r).flatten.compact.uniq
end

#registered=(v) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 525

def registered=(v) # :nodoc:
  @registered = v.nil? ? v : !!v
end

#registered?Boolean

Prior to BCP 178 (RFC 6648), it could be assumed that MIME content types that start with x- were unregistered MIME. Per this BCP, this assumption is no longer being made by default in this library.

There are three possible registration states for a MIME::Type:

  • Explicitly registered, like application/x-www-url-encoded.

  • Explicitly not registered, like image/webp.

  • Unspecified, in which case the media-type and the content-type will be scanned to see if they start with x-, indicating that they are assumed unregistered.

In mime-types 3, only a MIME content type that is explicitly registered will be used; there will be assumption that x- types are unregistered.


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# File 'lib/mime/type.rb', line 516

def registered?
  if @registered.nil?
    (@raw_media_type !~ UNREGISTERED_RE) and
      (@raw_sub_type !~ UNREGISTERED_RE)
  else
    !!@registered
  end
end

#signature=(v) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 549

def signature=(v) # :nodoc:
  @signature = !!v
end

#signature?Boolean

Returns true when the simplified MIME::Type is one of the known digital signature types.


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# File 'lib/mime/type.rb', line 545

def signature?
  !!@signature
end

#systemObject

If the MIME::Type is a system-specific MIME::Type, returns the regular expression for the operating system indicated.

This information about MIME content types is deprecated and will be removed in mime-types 3.


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# File 'lib/mime/type.rb', line 296

def system
  MIME::Types.deprecated(self, __method__)
  @system
end

#system=(os) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 301

def system=(os) # :nodoc:
  if os.nil? or os.kind_of?(Regexp)
    @system = os
  else
    @system = %r{#{os}}
  end
end

#system?(__internal__ = false) ⇒ Boolean

Returns true if the MIME::Type is specific to an operating system.

This method is deprecated and will be removed in mime-types 3.


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# File 'lib/mime/type.rb', line 556

def system?(__internal__ = false)
  MIME::Types.deprecated(self, __method__) unless __internal__
  !@system.nil?
end

#to_aObject

Returns the MIME::Type as an array suitable for use with MIME::Type.from_array.

This method is deprecated and will be removed in mime-types 3.


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# File 'lib/mime/type.rb', line 593

def to_a
  MIME::Types.deprecated(self, __method__)
  [ @content_type, @extensions, @encoding, @system, obsolete?, @docs,
    @references, registered? ]
end

#to_hObject

Converts the MIME::Type to a hash suitable for use in JSON. The output of this method can also be used to initialize a MIME::Type.


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# File 'lib/mime/type.rb', line 624

def to_h
  encode_with({})
end

#to_hashObject

Returns the MIME::Type as an array suitable for use with MIME::Type.from_hash.

This method is deprecated and will be removed in mime-types 3.


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# File 'lib/mime/type.rb', line 603

def to_hash
  MIME::Types.deprecated(self, __method__)
  { 'Content-Type'              => @content_type,
    'Content-Transfer-Encoding' => @encoding,
    'Extensions'                => @extensions,
    'System'                    => @system,
    'Obsolete'                  => obsolete?,
    'Docs'                      => @docs,
    'URL'                       => @references,
    'Registered'                => registered?,
  }
end

#to_json(*args) ⇒ Object

Converts the MIME::Type to a JSON string.


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# File 'lib/mime/type.rb', line 617

def to_json(*args)
  require 'json'
  to_h.to_json(*args)
end

#to_sObject

Returns the MIME::Type as a string.


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# File 'lib/mime/type.rb', line 577

def to_s
  content_type
end

#to_strObject

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('text/plain')

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# File 'lib/mime/type.rb', line 585

def to_str
  content_type
end

#urlObject


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# File 'lib/mime/type.rb', line 406

def url
  MIME::Types.deprecated(self, __method__)
  references(true)
end

#url=(r) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 412

def url=(r) # :nodoc:
  MIME::Types.deprecated(self, __method__)
  self.references = r
end

#urlsObject

The decoded URL list for this MIME::Type.

The special URL value IANA will be translated into:

http://www.iana.org/assignments/media-types/<mediatype>/<subtype>

The special URL value RFC### will be translated into:

http://www.rfc-editor.org/rfc/rfc###.txt

The special URL value DRAFT:name will be translated into:

https://datatracker.ietf.org/public/idindex.cgi?
    command=id_detail&filename=<name>

The special URL value [token] will be translated into:

http://www.iana.org/assignments/contact-people.htm#<token>

These values will be accessible through #urls, which always returns an array.

This method is deprecated and will be removed in mime-types 3.


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# File 'lib/mime/type.rb', line 451

def urls
  MIME::Types.deprecated(self, __method__)
  references(true).map do |el|
    case el
    when %r{^IANA$}
      IANA_URL % [ @media_type, @sub_type ]
    when %r{^RFC(\d+)$}
      RFC_URL % $1
    when %r{^DRAFT:(.+)$}
      DRAFT_URL % $1
    when %r{^\{([^=]+)=([^\}]+)\}}
      [$1, $2]
    when %r{^\[([^=]+)=([^\]]+)\]}
      [$1, CONTACT_URL % $2]
    when %r{^\[([^\]]+)\]}
      CONTACT_URL % $1
    else
      el
    end
  end
end

#xref_urlsObject

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


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# File 'lib/mime/type.rb', line 474

def xref_urls
  xrefs.flat_map { |(type, values)|
    case type
    when 'rfc'.freeze
      values.map { |data| 'http://www.iana.org/go/%s'.freeze % data }
    when 'draft'.freeze
      values.map { |data|
        'http://www.iana.org/go/%s'.freeze % data.sub(/\ARFC/, 'draft')
      }
    when 'rfc-errata'.freeze
      values.map { |data|
        'http://www.rfc-editor.org/errata_search.php?eid=%s'.freeze % data
      }
    when 'person'.freeze
      values.map { |data|
        'http://www.iana.org/assignments/media-types/media-types.xhtml#%s'.freeze % data # rubocop:disable Metrics/LineLength
      }
    when 'template'.freeze
      values.map { |data|
        'http://www.iana.org/assignments/media-types/%s'.freeze % data
      }
    else # 'uri', 'text', etc.
      values
    end
  }
end