module Mail::Encodings

Public Class Methods

address_encode(address, charset = 'utf-8') click to toggle source
# File lib/mail/encodings.rb, line 162
def Encodings.address_encode(address, charset = 'utf-8')
  if address.is_a?(Array)
    address.compact.map { |a| Encodings.address_encode(a, charset) }.join(", ")
  elsif address
    encode_non_usascii(address, charset)
  end
end
b_value_encode(string, encoding = nil) click to toggle source

Encode a string with Base64 Encoding and returns it ready to be inserted as a value for a field, that is, in the =?<charset>?B?<string>?= format

Example:

Encodings.b_value_encode('This is あ string', 'UTF-8')
#=> "=?UTF-8?B?VGhpcyBpcyDjgYIgc3RyaW5n?="
# File lib/mail/encodings.rb, line 199
def Encodings.b_value_encode(string, encoding = nil)
  if string.to_s.ascii_only?
    string
  else
    Encodings.each_base64_chunk_byterange(string, 60).map do |chunk|
      str, encoding = Utilities.b_value_encode(chunk, encoding)
      "=?#{encoding}?B?#{str.chomp}?="
    end.join(" ")
  end
end
decode_encode(str, output_type) click to toggle source

Decodes or encodes a string as needed for either Base64 or QP encoding types in the =?<encoding>??<string>?=“ format.

The output type needs to be :decode to decode the input string or :encode to encode the input string. The character set used for encoding will be the encoding on the string passed in.

On encoding, will only send out Base64 encoded strings.

# File lib/mail/encodings.rb, line 105
def Encodings.decode_encode(str, output_type)
  case
  when output_type == :decode
    Encodings.value_decode(str)
  else
    if str.ascii_only?
      str
    else
      Encodings.b_value_encode(str, str.encoding)
    end
  end
end
defined?(name) click to toggle source

Is the encoding we want defined?

Example:

Encodings.defined?(:base64) #=> true
# File lib/mail/encodings.rb, line 29
def Encodings.defined?(name)
  @transfer_encodings.include? get_name(name)
end
encode_non_usascii(address, charset) click to toggle source
# File lib/mail/encodings.rb, line 170
def Encodings.encode_non_usascii(address, charset)
  return address if address.ascii_only? or charset.nil?

  # Encode all strings embedded inside of quotes
  address = address.gsub(/("[^"]*[^\/]")/) { |s| Encodings.b_value_encode(unquote(s), charset) }

  # Then loop through all remaining items and encode as needed
  tokens = address.split(/\s/)

  map_with_index(tokens) do |word, i|
    if word.ascii_only?
      word
    else
      previous_non_ascii = i>0 && tokens[i-1] && !tokens[i-1].ascii_only?
      if previous_non_ascii #why are we adding an extra space here?
        word = " #{word}"
      end
      Encodings.b_value_encode(word, charset)
    end
  end.join(' ')
end
get_all() click to toggle source
# File lib/mail/encodings.rb, line 45
def Encodings.get_all
  @transfer_encodings.values
end
get_encoding(name) click to toggle source

Gets a defined encoding type, QuotedPrintable or Base64 for now.

Each encoding needs to be defined as a Mail::Encodings::ClassName for this to work, allows us to add other encodings in the future.

Example:

Encodings.get_encoding(:base64) #=> Mail::Encodings::Base64
# File lib/mail/encodings.rb, line 41
def Encodings.get_encoding(name)
  @transfer_encodings[get_name(name)]
end
get_name(name) click to toggle source
# File lib/mail/encodings.rb, line 49
def Encodings.get_name(name)
  underscoreize(name).downcase
end
param_decode(str, encoding) click to toggle source

Decodes a parameter value using URI Escaping.

Example:

Mail::Encodings.param_decode("This%20is%20fun", 'us-ascii') #=> "This is fun"

str = Mail::Encodings.param_decode("This%20is%20fun", 'iso-8559-1')
str.encoding #=> 'ISO-8859-1'      ## Only on Ruby 1.9
str #=> "This is fun"
# File lib/mail/encodings.rb, line 93
def Encodings.param_decode(str, encoding)
  Utilities.param_decode(str, encoding)
end
param_encode(str) click to toggle source

Encodes a parameter value using URI Escaping, note the language field ‘en’ can be set using Mail::Configuration, like so:

Mail.defaults do
  param_encode_language 'jp'
end

The character set used for encoding will be the encoding on the string passed in.

Example:

Mail::Encodings.param_encode("This is fun") #=> "us-ascii'en'This%20is%20fun"
# File lib/mail/encodings.rb, line 73
def Encodings.param_encode(str)
  case
  when str.ascii_only? && str =~ TOKEN_UNSAFE
    %Q{"#{str}"}
  when str.ascii_only?
    str
  else
    Utilities.param_encode(str)
  end
end
q_value_encode(encoded_str, encoding = nil) click to toggle source

Encode a string with Quoted-Printable Encoding and returns it ready to be inserted as a value for a field, that is, in the =?<charset>?Q?<string>?= format

Example:

Encodings.q_value_encode('This is あ string', 'UTF-8')
#=> "=?UTF-8?Q?This_is_=E3=81=82_string?="
# File lib/mail/encodings.rb, line 217
def Encodings.q_value_encode(encoded_str, encoding = nil)
  return encoded_str if encoded_str.to_s.ascii_only?
  string, encoding = Utilities.q_value_encode(encoded_str, encoding)
  string.gsub!("=\r\n", '') # We already have limited the string to the length we want
  map_lines(string) do |str|
    "=?#{encoding}?Q?#{str.chomp.gsub(/ /, '_')}?="
  end.join(" ")
end
register(name, cls) click to toggle source

Register transfer encoding

Example

Encodings.register “base64”, Mail::Encodings::Base64

# File lib/mail/encodings.rb, line 20
def Encodings.register(name, cls)
  @transfer_encodings[get_name(name)] = cls
end
transcode_charset(str, from_charset, to_charset = 'UTF-8') click to toggle source
# File lib/mail/encodings.rb, line 53
def Encodings.transcode_charset(str, from_charset, to_charset = 'UTF-8')
  if from_charset
    Utilities.transcode_charset str, from_charset, to_charset
  else
    str
  end
end
unquote_and_convert_to(str, to_encoding) click to toggle source

Takes an encoded string of the format =?<encoding>??<string>?=

# File lib/mail/encodings.rb, line 140
def Encodings.unquote_and_convert_to(str, to_encoding)
  output = value_decode( str ).to_s # output is already converted to UTF-8

  if 'utf8' == to_encoding.to_s.downcase.gsub("-", "")
    output
  elsif to_encoding
    begin
      output.encode(to_encoding)
    rescue Errno::EINVAL
      # the 'from' parameter specifies a charset other than what the text
      # actually is...not much we can do in this case but just return the
      # unconverted text.
      #
      # Ditto if either parameter represents an unknown charset, like
      # X-UNKNOWN.
      output
    end
  else
    output
  end
end
value_decode(str) click to toggle source

Decodes a given string as Base64 or Quoted Printable, depending on what type it is.

String has to be of the format =?<encoding>??<string>?=

# File lib/mail/encodings.rb, line 122
def Encodings.value_decode(str)
  # Optimization: If there's no encoded-words in the string, just return it
  return str unless str =~ ENCODED_VALUE

  lines = collapse_adjacent_encodings(str)

  # Split on white-space boundaries with capture, so we capture the white-space as well
  lines.each do |line|
    line.gsub!(ENCODED_VALUE) do |string|
      case $2
      when *B_VALUES then b_value_decode(string)
      when *Q_VALUES then q_value_decode(string)
      end
    end
  end.join("")
end

Private Class Methods

b_value_decode(str) click to toggle source

Decodes a Base64 string from the “=?UTF-8?B?VGhpcyBpcyDjgYIgc3RyaW5n?=” format

Example:

Encodings.b_value_decode("=?UTF-8?B?VGhpcyBpcyDjgYIgc3RyaW5n?=")
#=> 'This is あ string'
# File lib/mail/encodings.rb, line 234
def Encodings.b_value_decode(str)
  Utilities.b_value_decode(str)
end
collapse_adjacent_encodings(str) click to toggle source

Split header line into proper encoded and unencoded parts.

String has to be of the format =?<encoding>??<string>?=

Omit unencoded space after an encoded-word.

# File lib/mail/encodings.rb, line 258
def Encodings.collapse_adjacent_encodings(str)
  results = []
  last_encoded = nil  # Track whether to preserve or drop whitespace

  lines = str.split(FULL_ENCODED_VALUE)
  lines.each_slice(2) do |unencoded, encoded|
    if last_encoded = encoded
      if !Utilities.blank?(unencoded) || (!last_encoded && unencoded != EMPTY)
        results << unencoded
      end

      results << encoded
    else
      results << unencoded
    end
  end

  results
end
each_base64_chunk_byterange(str, max_bytesize_per_base64_chunk, &block) click to toggle source

Partition the string into bounded-size chunks without splitting multibyte characters.

# File lib/mail/encodings.rb, line 280
def Encodings.each_base64_chunk_byterange(str, max_bytesize_per_base64_chunk, &block)
  raise "size per chunk must be multiple of 4" if (max_bytesize_per_base64_chunk % 4).nonzero?

  if block_given?
    max_bytesize = ((3 * max_bytesize_per_base64_chunk) / 4.0).floor
    each_chunk_byterange(str, max_bytesize, &block)
  else
    enum_for :each_base64_chunk_byterange, str, max_bytesize_per_base64_chunk
  end
end
each_chunk_byterange(str, max_bytesize_per_chunk) { |string_byteslice| ... } click to toggle source

Partition the string into bounded-size chunks without splitting multibyte characters.

# File lib/mail/encodings.rb, line 293
def Encodings.each_chunk_byterange(str, max_bytesize_per_chunk)
  return enum_for(:each_chunk_byterange, str, max_bytesize_per_chunk) unless block_given?

  offset = 0
  chunksize = 0

  str.each_char do |chr|
    charsize = chr.bytesize

    if chunksize + charsize > max_bytesize_per_chunk
      yield Utilities.string_byteslice(str, offset, chunksize)
      offset += chunksize
      chunksize = charsize
    else
      chunksize += charsize
    end
  end

  yield Utilities.string_byteslice(str, offset, chunksize)
end
q_value_decode(str) click to toggle source

Decodes a Quoted-Printable string from the “=?UTF-8?Q?This_is_=E3=81=82_string?=” format

Example:

Encodings.q_value_decode("=?UTF-8?Q?This_is_=E3=81=82_string?=")
#=> 'This is あ string'
# File lib/mail/encodings.rb, line 244
def Encodings.q_value_decode(str)
  Utilities.q_value_decode(str)
end
value_encoding_from_string(str) click to toggle source

Gets the encoding type (Q or B) from the string.

# File lib/mail/encodings.rb, line 249
def Encodings.value_encoding_from_string(str)
  str[ENCODED_VALUE, 1]
end