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
rescue HTTP::Accept::ParseError
	# If we fail to parse the browser Accept-Language header, we ignore it (silently).
	return []
end

#call(env) ⇒ Object 



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# File 'lib/utopia/localization.rb', line 192

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 166

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 173

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