Class: DiskCacher

Inherits:
Object
  • Object
show all
Extended by:
DTK::Client::CommandBase
Includes:
DTK::Client::CommandBase
Defined in:
lib/config/disk_cacher.rb

Overview

Class dedicated for caching data on local system as well as for cookie management

Constant Summary collapse 

'tempdtkstore'
FILE_DELIMITER = 
'--'

Instance Method Summary collapse

Methods included from DTK::Client::CommandBase

get, get_connection, handle_argument_error, post, post_file, rest_url, rotate_args

Constructor Details

#initialize(cache_dir = DTK::Client::OsUtil.get_temp_location) ⇒ DiskCacher

Returns a new instance of DiskCacher.



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# File 'lib/config/disk_cacher.rb', line 35

def initialize(cache_dir = DTK::Client::OsUtil.get_temp_location)
  @cache_dir = cache_dir
  @current_user = ::DTK::Client::Configurator.client_username
end

Instance Method Details

#fetch(file_name, max_age = 0, use_mock_up = true) ⇒ Object 



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# File 'lib/config/disk_cacher.rb', line 40

def fetch(file_name, max_age = 0, use_mock_up = true)
  file = Digest::MD5.hexdigest(file_name)
  # current user is important so that there are no clashes in writting to temp file
  # between multiple users on same machine
  file_path = File.join(@cache_dir, "#{@current_user}#{FILE_DELIMITER}#{file}")

  # we check if the file -- a MD5 hexdigest of the URL -- exists
  #  in the dir. If it does and the data is fresh, we just read
  #  data from the file and return
  if File.exists? file_path
    return File.new(file_path).read if ((Time.now - File.mtime(file_path)) < max_age)
  end

  # if the file does not exist (or if the data is not fresh), we
  #  make an get request and save it to a file
  response_string = ""
  response = get rest_url("metadata/get_metadata/#{file_name}")

  if (response["status"] == "ok")
    file = File.open(file_path, "w") do |data|
      data << response_string = response["data"]
    end
  end

  return response_string
end

#load_cookie ⇒ Object 



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# File 'lib/config/disk_cacher.rb', line 74

def load_cookie
  file_path = File.join(@cache_dir, COOKIE_HOLDER_NAME)
  cookie_content = File.exists?(file_path) ? File.open(file_path) {|f| Marshal.load(f)} : nil
  cookie_content
end

#save_cookie(cookie_content) ⇒ Object 



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# File 'lib/config/disk_cacher.rb', line 67

def save_cookie(cookie_content)
  file_path = File.join(@cache_dir, COOKIE_HOLDER_NAME)
  File.open(file_path, "w") do |file|
    Marshal.dump(cookie_content, file)
  end
end