Class: AcceptLanguage::Matcher

Inherits:
Object
  • Object
show all
Defined in:
lib/accept_language/matcher.rb

Overview

A utility class that provides functionality to match the Accept-Language header value against the languages supported by your application. This helps in identifying the most suitable languages to present to the user based on their preferences.

Examples:

Matcher.new("da" => 1.0, "en-GB" => 0.8, "en" => 0.7).call(:ug, :kk, :ru, :en) # => :en
Matcher.new("da" => 1.0, "en-GB" => 0.8, "en" => 0.7).call(:fr, :en, :"en-GB") # => :"en-GB"

Constant Summary collapse

WILDCARD = 
"*"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(**languages_range) ⇒ Matcher

Initialize a new Matcher object with the languages_range parameter representing the user’s preferred languages and their respective quality values.

Parameters:

  • languages_range (Hash<String, BigDecimal>) —

    A hash where keys represent languages and values are the quality of preference for each language. A value of zero means the language is not acceptable.



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# File 'lib/accept_language/matcher.rb', line 21

def initialize(**languages_range)
  @excluded_langtags = ::Set[]
  langtags = []

  languages_range.select do |langtag, quality|
    if quality.zero?
      @excluded_langtags << langtag unless wildcard?(langtag)
    else
      level = (quality * 1_000).to_i
      langtags[level] = langtag
    end
  end

  @preferred_langtags = langtags.compact.reverse
end

Instance Attribute Details

#excluded_langtags ⇒ Object (readonly)

Returns the value of attribute excluded_langtags.



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# File 'lib/accept_language/matcher.rb', line 14

def excluded_langtags
  @excluded_langtags
end

#preferred_langtags ⇒ Object (readonly)

Returns the value of attribute preferred_langtags.



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# File 'lib/accept_language/matcher.rb', line 14

def preferred_langtags
  @preferred_langtags
end

Instance Method Details

#call(*available_langtags) ⇒ String, ...

Matches the user’s preferred languages against the available languages of your application. It prioritizes higher quality values and returns the most suitable match.

Examples:

When Uyghur, Kazakh, Russian and English languages are available.

call(:ug, :kk, :ru, :en)

Parameters:

  • available_langtags (Array<String, Symbol>) —

    An array representing the languages available in your application.

Returns:

  • (String, Symbol, nil) —

    The language that best matches the user’s preferences, or nil if there is no match.



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# File 'lib/accept_language/matcher.rb', line 46

def call(*available_langtags)
  available_langtags = drop_unacceptable(*available_langtags)

  preferred_langtags.each do |preferred_tag|
    if wildcard?(preferred_tag)
      langtag = any_other_langtag(*available_langtags)
      return langtag unless langtag.nil?
    else
      available_langtags.each do |available_langtag|
        return available_langtag if available_langtag.match?(/\A#{preferred_tag}/i)
      end
    end
  end

  nil
end