Class: Utopia::Localization

Inherits:
Object
  • Object
show all
Defined in:
lib/utopia/localization.rb

Overview

If you request a URL which has localized content, a localized redirect would be returned based on the content requested.

Defined Under Namespace

Classes: Wrapper

Constant Summary collapse

RESOURCE_NOT_FOUND = 
[400, {}, []].freeze
HTTP_ACCEPT_LANGUAGE = 
'HTTP_ACCEPT_LANGUAGE'.freeze
LOCALIZATION_KEY = 
'utopia.localization'.freeze
CURRENT_LOCALE_KEY = 
'utopia.localization.current_locale'.freeze
DEFAULT_LOCALE = 
'en'
HTTP_HOST = 
'HTTP_HOST'.freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app, **options) ⇒ Localization

Returns a new instance of Localization.



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# File 'lib/utopia/localization.rb', line 64

def initialize(app, **options)
  @app = app
  
  @all_locales = HTTP::Accept::Languages::Locales.new(options[:locales])
  
  # Locales here are represented as an array of strings, e.g. ['en', 'ja', 'cn', 'de'].
  unless @default_locales = options[:default_locales] 
    # We append nil, i.e. no localization.
    @default_locales = @all_locales.names + [nil]
  end
  
  if @default_locale = options[:default_locale]
    @default_locales.unshift(default_locale)
  else
    @default_locale = @default_locales.first
  end
  
  @hosts = options[:hosts] || {}
  
  @nonlocalized = options.fetch(:nonlocalized, [])
  
  self.freeze
end

Instance Attribute Details

#all_locales ⇒ Object (readonly)

Returns the value of attribute all_locales.



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# File 'lib/utopia/localization.rb', line 98

def all_locales
  @all_locales
end

#default_locale ⇒ Object (readonly)

Returns the value of attribute default_locale.



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# File 'lib/utopia/localization.rb', line 99

def default_locale
  @default_locale
end

Class Method Details

.[](request) ⇒ Object 



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# File 'lib/utopia/localization.rb', line 52

def self.[] request
  Wrapper.new(request.env)
end

Instance Method Details

#browser_preferred_locales(env) ⇒ Object 



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# File 'lib/utopia/localization.rb', line 150

def browser_preferred_locales(env)
  accept_languages = env[HTTP_ACCEPT_LANGUAGE]
  
  # No user prefered languages:
  return [] unless accept_languages
  
  # Extract the ordered list of languages:
  languages = HTTP::Accept::Languages.parse(accept_languages)
  
  # Returns available languages based on the order languages:
  return @all_locales & languages
end

#call(env) ⇒ Object 



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# File 'lib/utopia/localization.rb', line 189

def call(env)
  # Pass the request through with no localization if it is a nonlocalized path:
  return @app.call(env) if nonlocalized?(env)
  
  env[LOCALIZATION_KEY] = self
  
  response = nil
  
  # We have a non-localized request, but there might be a localized resource. We return the best localization possible:
  preferred_locales(env) do |localized_env|
    # puts "Trying locale: #{env[CURRENT_LOCALE_KEY]}: #{env[Rack::PATH_INFO]}..."
    
    response = @app.call(localized_env)
    
    break unless response[0] >= 400
  end
  
  return vary(env, response)
end

#freeze ⇒ Object 



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# File 'lib/utopia/localization.rb', line 88

def freeze
  @all_locales.freeze
  @default_locales.freeze
  @default_locale.freeze
  @hosts.freeze
  @nonlocalized.freeze
  
  super
end

#host_preferred_locales(env) ⇒ Object 



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# File 'lib/utopia/localization.rb', line 129

def host_preferred_locales(env)
  http_host = env[Rack::HTTP_HOST]
  
  # Get a list of all hosts which match the incoming htt_host:
  matching_hosts = @hosts.select{|host_pattern, locale| http_host =~ host_pattern}
  
  # Extract all the valid locales:
  matching_hosts.flat_map{|host_pattern, locale| locale}
end

#nonlocalized?(env) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/utopia/localization.rb', line 163

def nonlocalized?(env)
  path_info = env[Rack::PATH_INFO]
  
  @nonlocalized.any? { |pattern| path_info[pattern] != nil }
end

#preferred_locales(env) ⇒ Object 



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# File 'lib/utopia/localization.rb', line 101

def preferred_locales(env)
  return to_enum(:preferred_locales, env) unless block_given?
  
  # Keep track of what locales have been tried:
  locales = Set.new
  
  host_preferred_locales(env).each do |locale|
    yield env.merge(CURRENT_LOCALE_KEY => locale) if locales.add? locale
  end
  
  request_preferred_locale(env) do |locale, path|
    # We have extracted a locale from the path, so from this point on we should use the updated path:
    env = env.merge(Rack::PATH_INFO => path.to_s)
    
    yield env.merge(CURRENT_LOCALE_KEY => locale) if locales.add? locale
  end
  
  browser_preferred_locales(env).each do |locale|
    yield env.merge(CURRENT_LOCALE_KEY => locale) if locales.add? locale
  end
  
  @default_locales.each do |locale|
    yield env.merge(CURRENT_LOCALE_KEY => locale) if locales.add? locale
  end
end

#request_preferred_locale(env) ⇒ Object 



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# File 'lib/utopia/localization.rb', line 139

def request_preferred_locale(env)
  path = Path[env[Rack::PATH_INFO]]
  
  if request_locale = @all_locales.patterns[path.first]
    # Remove the localization prefix:
    path.delete_at(0)
    
    yield request_locale, path
  end
end

#vary(env, response) ⇒ Object

Set the Vary: header on the response to indicate that this response should include the header in the cache key.



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# File 'lib/utopia/localization.rb', line 170

def vary(env, response)
  headers = response[1]
  
  # This response was based on the Accept-Language header:
  if headers['Vary']
    headers['Vary'] += ',Accept-Language'
  else
    headers['Vary'] = 'Accept-Language'
  end
  
  # Althought this header is generally not supported, we supply it anyway as it is useful for debugging:
  if locale = env[CURRENT_LOCALE_KEY]
    # Set the Content-Location to point to the localized URI as requested:
    headers['Content-Location'] = "/#{locale}" + env[Rack::PATH_INFO]
  end
  
  return response
end