Class: RailsAssetsCdn::Railtie

Inherits:
Rails::Railtie
  • Object
show all
Defined in:
lib/rails-assets-cdn/rails-assets-cdn.rb

Instance Method Summary collapse

Instance Method Details

#initialize_railtie ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/rails-assets-cdn/rails-assets-cdn.rb', line 3

def initialize_railtie
  Rails.logger.info "Initializing rails-assets-cdn..."
  $rails_assets_cdn_initialized = false

  config = nil
  %w(assets_cdn.yml cdn.yml).each do |filename|
    config_path = Rails.root.join('config', filename).to_s
    if File.exist?(config_path)
      Rails.logger.info "  Reading config file at #{config_path}..."
      config = YAML.load_file(config_path)[Rails.env]
      break
    end
  end

  unless config
    Rails.logger.info "  Couldn't find configuration file. Skipping initialization."
    return false
  end

  # Set defaults
  config['enabled']           = true      if config['enabled'].nil?
  config['protocol']          = 'browser' if config['protocol'].nil?
  config['fallback_protocol'] = 'http'    if config['fallback_protocol'].nil?
  config['protocol'].sub!('://', '')
  config['fallback_protocol'].sub!('://', '')

  # Validations
  unless config['enabled']
    Rails.logger.info "  rails-assets-cdn is disabled. Bye bye!"
    return false
  end

  raise ArgumentError.new("Protocol #{config["protocol"]} is invalid.") \
    unless %w(browser request http https).include?(config['protocol'])
  raise ArgumentError.new("Fallback protocol #{config["fallback_protocol"]} is invalid.") \
    unless %w(http https).include?(config['fallback_protocol'])
  raise ArgumentError.new("CDN hosts not specified.") \
    unless (config['hosts'] || config['host']).present?

  $rails_assets_cdn = {}
  $rails_assets_cdn[:hosts]             = Array.wrap(config['hosts'] || config['host'])
  $rails_assets_cdn[:fallback_protocol] = config['fallback_protocol'] + "://"
  $rails_assets_cdn[:protocol]     = case config['protocol'].to_sym
    when :browser; '//'           # Let browser decide on protocol
    when :request; nil            # Same protocol as the current request, but hardcoded
    when :http;    'http://'      # Force http
    when :https;   'https://'     # Force https
  end

  Rails.logger.info "  CDN hosts: #{$rails_assets_cdn[:hosts].to_sentence}."
  Rails.logger.info "  Protocol strategy: #{$rails_assets_cdn[:protocol]} (fallback: #{$rails_assets_cdn[:fallback_protocol]})."

  ActionController::Base.asset_host = Proc.new do |source, request|
    protocol = if $rails_assets_cdn[:protocol]
      $rails_assets_cdn[:protocol]
    else
      request ? request.protocol : $rails_assets_cdn[:fallback_protocol]
    end

    $rails_assets_cdn[:hosts].map { |host| protocol.to_s + host }[source.hash % $rails_assets_cdn[:hosts].size]
  end

  $rails_assets_cdn[:initialized] = true
end