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

Defined Under Namespace

Classes: InvalidContentType, InvalidEncoding

Constant Summary collapse

VERSION =

The released version of the mime-types library.

'2.5'

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 provided 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:

  • (_self)

Yield Parameters:

  • _self (MIME::Type)

    the object that the method was called on


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# File 'lib/mime/type.rb', line 95

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         ||= nil
  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 202

def content_type
  @content_type
end

#docsObject

The documentation for this MIME::Type.


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# File 'lib/mime/type.rb', line 319

def docs
  @docs
end

#encodingObject

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.


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# File 'lib/mime/type.rb', line 266

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 235

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 350

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 215

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 220

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 230

def raw_sub_type
  @raw_sub_type
end

#referencesObject

The encoded references URL list for this MIME::Type. See #urls for more information.

This was previously called #url.


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# File 'lib/mime/type.rb', line 356

def references
  @references
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 210

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 225

def sub_type
  @sub_type
end

#use_insteadObject

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.


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# File 'lib/mime/type.rb', line 303

def use_instead
  return nil unless obsolete?
  @use_instead
end

#xrefsObject

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


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# File 'lib/mime/type.rb', line 373

def xrefs
  @xrefs
end

Class Method Details

.from_array(*args) ⇒ Object

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

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

extensions, encoding, and system are optional.

MIME::Type.from_array("application/x-ruby", ['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

This method is deprecated.


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# File 'lib/mime/type.rb', line 668

def from_array(*args) # :yields MIME::Type.new:
  MIME.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)
    raise 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

This method has been deprecated.


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# File 'lib/mime/type.rb', line 709

def from_hash(hash) # :yields MIME::Type.new:
  MIME.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.

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

This method has been deprecated.


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# File 'lib/mime/type.rb', line 742

def from_mime_type(mime_type) # :yields the new MIME::Type:
  MIME.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 634

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

  if matchdata
    matchdata.captures.map { |e|
      e.downcase!
      e.gsub!(UNREGISTERED_RE, ''.freeze)
      e.gsub!(I18N_RE, '-'.freeze)
      e
    }.join('.'.freeze)
  end
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 can disappear, adds to the confusing proliferation of MIME types. The simplified string has the x- removed and are translated to lowercase.


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# File 'lib/mime/type.rb', line 615

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

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

Instance Method Details

#<=>(other) ⇒ Object

Compares the 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 140

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(*ext) ⇒ 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 242

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

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 479

def ascii?
  not 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.

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 472

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.

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 512

def complete?
  not @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 295

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.


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# File 'lib/mime/type.rb', line 570

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 unless references.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.

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 189

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

#friendly(lang = 'en') ⇒ 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 326

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

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

#init_with(coder) ⇒ Object

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


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# File 'lib/mime/type.rb', line 590

def init_with(coder)
  self.content_type = coder['content-type']
  self.docs         = coder['docs'] || []
  self.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 simplified type matches the current

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 128

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 314

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

#obsolete?Boolean

Returns true if the media type is obsolete.

Returns:

  • (Boolean)

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

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.

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 505

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

#preferred_extensionObject


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# File 'lib/mime/type.rb', line 252

def preferred_extension
  extensions.first
end

#priority_compare(other) ⇒ Object

Compares the 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.


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# File 'lib/mime/type.rb', line 160

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

#registered=(v) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 465

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.

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 456

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 489

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

#signature?Boolean

Returns true when the simplified MIME::Type is in the list of known digital signatures.

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 485

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.


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# File 'lib/mime/type.rb', line 281

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

#system=(os) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 286

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.

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 496

def system?(__internal__ = false)
  MIME.deprecated(self, __method__) unless __internal__
  not @system.nil?
end

#to_aObject

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

This method is deprecated.


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# File 'lib/mime/type.rb', line 533

def to_a
  MIME.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 563

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.


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# File 'lib/mime/type.rb', line 543

def to_hash
  MIME.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 557

def to_json(*args)
  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 517

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 525

def to_str
  content_type
end

#urlObject

:nodoc:


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# File 'lib/mime/type.rb', line 362

def url # :nodoc:
  MIME.deprecated(self, __method__, "and has been renamed to #references")
  references
end

#url=(r) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 367

def url=(r) # :nodoc:
  MIME.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.


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# File 'lib/mime/type.rb', line 397

def urls
  references.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 419

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