Module: S3Columns::ClassMethods

Defined in:
lib/ar_s3_columns/class_methods.rb

Instance Method Summary collapse

Instance Method Details

#s3_column_for(column_name, options = {}) ⇒ Object

Creates reader/writer for given column that will upload the marshalled value to S3 Options:

* s3_key: S3 key to use, should be a Proc.
* s3_bucket: S3 bucket to use



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# File 'lib/ar_s3_columns/class_methods.rb', line 16

def s3_column_for(column_name, options={})
  raise "Please set a S3Columns.default_aws_bucket" if S3Columns.default_aws_bucket.blank?
  options[:s3_key]  ||= Proc.new{|object| "#{object.class.name}/#{column_name}/#{SimpleUUID::UUID.new.to_guid}"}
  options[:s3_bucket]    ||= S3Columns.default_aws_bucket
  self.s3_columns ||= []
  self.s3_columns_keys ||= {}
  self.s3_columns << column_name unless self.s3_columns.include?(column_name)
  self.s3_columns_keys[column_name.to_sym] = options[:s3_key]
  self.s3_columns_buckets ||= {}
  self.s3_columns_buckets[column_name.to_sym] = options[:s3_bucket]
  
  # Creates a reader
  self.class_eval %Q{
    def s3_column_#{column_name}
      if self.persisted? && key_path = read_attribute(:#{column_name})
        key = S3Columns.s3_connection.buckets["#{options[:s3_bucket]}"].objects[key_path]
        # Retry in case it is not persisted in S3 yet
        Retryable.retryable :on => [AWS::S3::Errors::NoSuchKey], :tries => 10, :sleep => 1 do
          @#{column_name} ||= Marshal.load(key.read)
        end
      else
        @#{column_name}
      end
    end
  }
  
  # Creates writer
  self.class_eval %Q{
    def s3_column_#{column_name}=(value)
      marshalled_value = Marshal.dump(value)
      key_path = self.class.s3_columns_keys[:#{column_name}].call(self)
      write_options = S3Columns.default_s3_write_options || {}
      S3Columns.s3_connection.buckets["#{options[:s3_bucket]}"].objects[key_path].write(marshalled_value, write_options)
      # update column with new key
      write_attribute(:#{column_name}, key_path)
      @#{column_name} = value
    end
  }
end

#s3_column_upload_on_create ⇒ Object

Adds before_create to upload each S3 column to S3, to prevent it writing the values to DB. Warning: The default s3_key uses the object’s ID which will be nil at this point, should set a custom :s3_key



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# File 'lib/ar_s3_columns/class_methods.rb', line 6

def s3_column_upload_on_create
  self.class_eval %Q{
    before_create :s3_column_upload_on_create
  }
end