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'] # => [ 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('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'

Direct Known Subclasses

Columnar

Defined Under Namespace

Classes: Columnar, InvalidContentType, InvalidEncoding

Constant Summary collapse

VERSION =

The released version of the mime-types library.

"3.4.1"

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 'application/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 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.

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 125

def initialize(content_type) # :yields: self
  @friendly = {}
  @obsolete = @registered = @provisional = false
  @preferred_extension = @docs = @use_instead = nil
  self.extensions = []

  case content_type
  when Hash
    init_with(content_type)
  when Array
    self.content_type = content_type.shift
    self.extensions = content_type.flatten
  when MIME::Type
    init_with(content_type.to_h)
  else
    self.content_type = content_type
  end

  self.encoding ||= :default
  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 262

def content_type
  @content_type
end

#docsObject

The documentation for this MIME::Type.


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# File 'lib/mime/type.rb', line 390

def docs
  @docs
end

#encodingObject

Returns the value of attribute encoding.


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# File 'lib/mime/type.rb', line 352

def encoding
  @encoding
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 422

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  => x-chemical
audio/QCELP       => audio

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# File 'lib/mime/type.rb', line 275

def media_type
  @media_type
end

#obsoleteObject Also known as: obsolete?

Returns true if the media type is obsolete.


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# File 'lib/mime/type.rb', line 386

def obsolete
  @obsolete
end

#provisionalObject

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


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# File 'lib/mime/type.rb', line 450

def provisional
  @provisional
end

#raw_media_typeObject (readonly)

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

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

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

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
audio/QCELP       => qcelp

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# File 'lib/mime/type.rb', line 293

def raw_sub_type
  @raw_sub_type
end

#registeredObject Also known as: registered?

Indicates whether the MIME type has been registered with IANA.


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# File 'lib/mime/type.rb', line 446

def registered
  @registered
end

#signatureObject Also known as: signature?

Indicateswhether the MIME type is declared as a signature type.


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

def signature
  @signature
end

#simplifiedObject (readonly)

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

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# File 'lib/mime/type.rb', line 269

def simplified
  @simplified
end

#sub_typeObject (readonly)

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

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

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# File 'lib/mime/type.rb', line 287

def sub_type
  @sub_type
end

#use_insteadObject


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# File 'lib/mime/type.rb', line 378

def use_instead
  obsolete? ? @use_instead : nil
end

#xrefsObject

Returns the value of attribute xrefs.


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# File 'lib/mime/type.rb', line 430

def xrefs
  @xrefs
end

Class Method Details

.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 576

def i18n_key(content_type)
  simplify_matchdata(match(content_type), joiner: ".") { |e|
    e.gsub!(I18N_RE, "-")
  }
end

.match(content_type) ⇒ Object

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


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# File 'lib/mime/type.rb', line 584

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

.simplified(content_type, remove_x_prefix: false) ⇒ Object

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.


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

def simplified(content_type, remove_x_prefix: false)
  simplify_matchdata(match(content_type), remove_x_prefix)
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 165

def <=>(other)
  if other.nil?
    -1
  elsif other.respond_to?(:simplified)
    simplified <=> other.simplified
  else
    filtered = "silent" if other == :silent
    filtered ||= "true" if other == true
    filtered ||= other.to_s

    simplified <=> MIME::Type.simplified(filtered)
  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 313

def add_extensions(*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.

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 467

def ascii?
  ASCII_ENCODINGS.include?(encoding)
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 460

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 477

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 366

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 511

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
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 223

def eql?(other)
  other.is_a?(MIME::Type) && (self == other)
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.

:attr_accessor: extensions


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

def extensions
  @extensions.to_a
end

#extensions=(value) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 306

def extensions=(value) # :nodoc:
  @extensions = Set[*Array(value).flatten.compact].freeze
  MIME::Types.send(:reindex_extensions, self)
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 397

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

#hashObject

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's suitable for #hash to delegate to #simplified in service of the #eql? invariant.


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# File 'lib/mime/type.rb', line 249

def hash
  simplified.hash
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 540

def init_with(coder)
  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"] || {})
end

#inspectObject

:nodoc:


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

def inspect # :nodoc:
  # We are intentionally lying here because MIME::Type::Columnar is an
  # implementation detail.
  "#<MIME::Type: #{self}>"
end

#like?(other) ⇒ Boolean

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

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 151

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

#preferred_extensionObject


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# File 'lib/mime/type.rb', line 327

def preferred_extension
  @preferred_extension || extensions.first
end

#preferred_extension=(value) ⇒ Object

:nodoc:


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# File 'lib/mime/type.rb', line 332

def preferred_extension=(value) # :nodoc:
  add_extensions(value) if value
  @preferred_extension = value
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. Complete definitions < incomplete definitions.

  4. Current definitions < obsolete definitions.

  5. Obselete with use-instead names < obsolete without.

  6. 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 195

def priority_compare(other)
  pc = simplified <=> other.simplified
  if pc.zero? || !(extensions & other.extensions).empty?
    pc =
      if (reg = registered?) != other.registered?
        reg ? -1 : 1 # registered < unregistered
      elsif (comp = complete?) != other.complete?
        comp ? -1 : 1 # complete < incomplete
      elsif (obs = obsolete?) != other.obsolete?
        obs ? 1 : -1 # current < obsolete
      elsif obs && ((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

#provisional?Boolean

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

Returns:

  • (Boolean)

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# File 'lib/mime/type.rb', line 453

def provisional?
  registered? && @provisional
end

#to_hObject

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


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# File 'lib/mime/type.rb', line 502

def to_h
  encode_with({})
end

#to_json(*args) ⇒ Object

Converts the MIME::Type to a JSON string.


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# File 'lib/mime/type.rb', line 495

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 482

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 490

def to_str
  content_type
end

#xref_urlsObject

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


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# File 'lib/mime/type.rb', line 438

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