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# frozen_string_literal: true
require "active_support/core_ext/string/multibyte"
require "active_support/i18n"
module ActiveSupport
module Inflector
# Replaces non-ASCII characters with an ASCII approximation, or if none
# exists, a replacement character which defaults to "?".
#
# transliterate('Ærøskøbing')
# # => "AEroskobing"
#
# Default approximations are provided for Western/Latin characters,
# e.g, "ø", "ñ", "é", "ß", etc.
#
# This method is I18n aware, so you can set up custom approximations for a
# locale. This can be useful, for example, to transliterate German's "ü"
# and "ö" to "ue" and "oe", or to add support for transliterating Russian
# to ASCII.
#
# In order to make your custom transliterations available, you must set
# them as the <tt>i18n.transliterate.rule</tt> i18n key:
#
# # Store the transliterations in locales/de.yml
# i18n:
# transliterate:
# rule:
# ü: "ue"
# ö: "oe"
#
# # Or set them using Ruby
# I18n.backend.store_translations(:de, i18n: {
# transliterate: {
# rule: {
# 'ü' => 'ue',
# 'ö' => 'oe'
# }
# }
# })
#
# The value for <tt>i18n.transliterate.rule</tt> can be a simple Hash that
# maps characters to ASCII approximations as shown above, or, for more
# complex requirements, a Proc:
#
# I18n.backend.store_translations(:de, i18n: {
# transliterate: {
# rule: ->(string) { MyTransliterator.transliterate(string) }
# }
# })
#
# Now you can have different transliterations for each locale:
#
# transliterate('Jürgen', locale: :en)
# # => "Jurgen"
#
# transliterate('Jürgen', locale: :de)
# # => "Juergen"
#
# Transliteration is restricted to UTF-8, US-ASCII and GB18030 strings
# Other encodings will raise an ArgumentError.
def transliterate(string, replacement = "?", locale: nil)
raise ArgumentError, "Can only transliterate strings. Received #{string.class.name}" unless string.is_a?(String)
allowed_encodings = [Encoding::UTF_8, Encoding::US_ASCII, Encoding::GB18030]
raise ArgumentError, "Can not transliterate strings with #{string.encoding} encoding" unless allowed_encodings.include?(string.encoding)
input_encoding = string.encoding
# US-ASCII is a subset of UTF-8 so we'll force encoding as UTF-8 if
# US-ASCII is given. This way we can let tidy_bytes handle the string
# in the same way as we do for UTF-8
string.force_encoding(Encoding::UTF_8) if string.encoding == Encoding::US_ASCII
# GB18030 is Unicode compatible but is not a direct mapping so needs to be
# transcoded. Using invalid/undef :replace will result in loss of data in
# the event of invalid characters, but since tidy_bytes will replace
# invalid/undef with a "?" we're safe to do the same beforehand
string.encode!(Encoding::UTF_8, invalid: :replace, undef: :replace) if string.encoding == Encoding::GB18030
transliterated = I18n.transliterate(
ActiveSupport::Multibyte::Unicode.tidy_bytes(string).unicode_normalize(:nfc),
replacement: replacement,
locale: locale
)
# Restore the string encoding of the input if it was not UTF-8.
# Apply invalid/undef :replace as tidy_bytes does
transliterated.encode!(input_encoding, invalid: :replace, undef: :replace) if input_encoding != transliterated.encoding
transliterated
end
# Replaces special characters in a string so that it may be used as part of
# a 'pretty' URL.
#
# parameterize("Donald E. Knuth") # => "donald-e-knuth"
# parameterize("^très|Jolie-- ") # => "tres-jolie"
#
# To use a custom separator, override the +separator+ argument.
#
# parameterize("Donald E. Knuth", separator: '_') # => "donald_e_knuth"
# parameterize("^très|Jolie__ ", separator: '_') # => "tres_jolie"
#
# To preserve the case of the characters in a string, use the +preserve_case+ argument.
#
# parameterize("Donald E. Knuth", preserve_case: true) # => "Donald-E-Knuth"
# parameterize("^très|Jolie-- ", preserve_case: true) # => "tres-Jolie"
#
# It preserves dashes and underscores unless they are used as separators:
#
# parameterize("^très|Jolie__ ") # => "tres-jolie__"
# parameterize("^très|Jolie-- ", separator: "_") # => "tres_jolie--"
# parameterize("^très_Jolie-- ", separator: ".") # => "tres_jolie--"
#
# If the optional parameter +locale+ is specified,
# the word will be parameterized as a word of that language.
# By default, this parameter is set to <tt>nil</tt> and it will use
# the configured <tt>I18n.locale<tt>.
def parameterize(string, separator: "-", preserve_case: false, locale: nil)
# Replace accented chars with their ASCII equivalents.
parameterized_string = transliterate(string, locale: locale)
# Turn unwanted chars into the separator.
parameterized_string.gsub!(/[^a-z0-9\-_]+/i, separator)
unless separator.nil? || separator.empty?
if separator == "-"
re_duplicate_separator = /-{2,}/
re_leading_trailing_separator = /^-|-$/i
else
re_sep = Regexp.escape(separator)
re_duplicate_separator = /#{re_sep}{2,}/
re_leading_trailing_separator = /^#{re_sep}|#{re_sep}$/i
end
# No more than one of the separator in a row.
parameterized_string.gsub!(re_duplicate_separator, separator)
# Remove leading/trailing separator.
parameterized_string.gsub!(re_leading_trailing_separator, "")
end
parameterized_string.downcase! unless preserve_case
parameterized_string
end
end
end
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