Class: TheCity::JsonCache

Inherits:
CacheAdapter show all
Defined in:
lib/cachers/file/json_cache.rb

Overview

This class caches the data in a JSON file.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ JsonCache

Constructor.



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# File 'lib/cachers/file/json_cache.rb', line 13

def initialize() 
  super
  @cache_dir = THECITY_STORAGE_DIR + subdomain + '/';
end

Instance Method Details

#expire_cache!(key) ⇒ Object

Expire the cache.

Parameters:

  • string —

    key The key to use to expire the cache.



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# File 'lib/cachers/file/json_cache.rb', line 74

def expire_cache!(key) 
  file = _find_file_key(key)
  unless file.nil? 
    begin
      File.unlink(@cache_dir + file)
    rescue
      raise new Exception("Unable to remove cache file: $file")
    end
  end
end

#get_cache_file(key) ⇒ Object

Get the file name where the cache is stored.

Parameters:

  • string —

    $key The key used for the cache.

Returns:

  • mixed Returns the name of the cache file if found or false.



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# File 'lib/cachers/file/json_cache.rb', line 50

def get_cache_file(key)
  _find_file_key(key)
end

#get_data(key) ⇒ Object

Get the data from the cache.

Parameters:

  • string —

    key The key to use to get the cache.

Returns:

  • JSON data.



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# File 'lib/cachers/file/json_cache.rb', line 60

def get_data(key) 
  filename = _find_file_key(key)
  return nil if filename.nil?
  file = File.open(@cache_dir + filename, "rb")
  contents = file.read
  return Marshal.load(contents)
end

#is_cache_expired?(key) ⇒ Boolean

Check if the cache has expired.

Parameters:

  • string —

    key The key to use to check if the cache has expired.

Returns:

  • (Boolean) —

    boolean If the cache does not exist or is expired then true, otherwise false.



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# File 'lib/cachers/file/json_cache.rb', line 91

def is_cache_expired?(key)
  time_stamp_position = 1;
  fname = _find_file_key(key)
  return true if fname.nil?

  fname_a = fname.split('-')
  if Time.now.to_i > fname_a[time_stamp_position].to_i
    return true
  end

  return false;
end

#save_data(key, data, expire_in = nil) ⇒ Object

Save data to the cache.

Parameters:

  • string —

    key The key to use to save the cache.

  • string —

    data The JSON data to be saved.

  • string —

    expire_in The number of seconds to pass before expiring the cache.

Returns:

  • mixed Returns true on success or a string error message on false.



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# File 'lib/cachers/file/json_cache.rb', line 26

def save_data(key, data, expire_in = nil)
  expire_in = 3600 if expire_in.nil?  # 3600 seconds = 1 hour
  expire_in += Time.now.to_i

  _create_cache_directory_if_needed
  expire_cache!(key)

  filename = "#{key}-#{expire_in}-json.cache"

  begin
    File.open(@cache_dir + filename, 'w') {|f| f.write( Marshal.dump(data) ) }
  rescue
    return 'Unable to write to file'
  end

  return true   
end