Module: ChromembedRails::Model

Extended by:
ActiveSupport::Concern
Included in:
ChromeExtensionCache
Defined in:
lib/chromembed_rails/model.rb

Overview

Included by the model caching data for serving an embedded Chrome extension.

Defined Under Namespace

Modules: ClassMethods

Instance Method Summary collapse

Instance Method Details

#update_with_current_bits(manifest_changes) ⇒ Object

Updates this cache entry to reflect the current extension code.

Args:

manifest_changes:: hash to be merged into the extension's manifest JSON;
                   'update_url' and 'version' might be good keys to change



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# File 'lib/chromembed_rails/model.rb', line 39

def update_with_current_bits(manifest_changes)
  extension_path = ChromembedRails.extension_path
  manifest_path = File.join extension_path, 'manifest.json'
  manifest_json = ActiveSupport::JSON.decode File.read(manifest_path)
  manifest_json.merge! manifest_changes
  self.version = manifest_json['version']

  key_path = ChromembedRails.key_path
  key = OpenSSL::PKey::RSA.new File.read(key_path)
  # Source: http://supercollider.dk/2010/01/calculating-chrome-extension-id-from-your-private-key-233
  alg = ["30819F300D06092A864886F70D010101050003818D00"].pack('H*')
  hash = Digest::SHA256.hexdigest(alg + key.public_key.to_der)[0...32]
  self.appid = hash.unpack('C*').map{ |c| c < 97 ? c + 49 : c + 10 }.
                    pack('C*')
  
  tmp_path = Rails.root.join 'tmp', "chrome_ext_#{Time.now.to_f}_#{$PID}"
  ext_path = File.join tmp_path, 'chrome_extension'
  FileUtils.mkdir_p ext_path
  FileUtils.cp_r File.join(extension_path, '.'), ext_path
  man_path = File.join ext_path, 'manifest.json'
  File.open(man_path, 'wb') do |f|
    f.write ActiveSupport::JSON.encode manifest_json
  end
  
  crx_path = File.join tmp_path, 'chrome_extension.crx'
  CrxMake.make :ex_dir => ext_path, :pkey => key_path,
               :crx_output => crx_path, :verbose => false
  self.crx_bits = File.read crx_path
  FileUtils.rm_r tmp_path
  
  self
end