Class: Reading::Parsing::Transformer

Inherits:
Object
  • Object
show all
Defined in:
lib/reading/parsing/transformer.rb

Overview

Transforms an intermediate hash (parsed from a CSV row) into item data. While the intermediate hash mirrors the structure of a row, the output of Transformer is based around item attributes, which are listed in Config#default_config[:template] and in the files in parsing/attributes.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Transformer

Returns a new instance of Transformer.



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# File 'lib/reading/parsing/transformer.rb', line 25

def initialize
  set_attributes
end

Instance Method Details

#transform_intermediate_hash_to_item_hashes(parsed_row) ⇒ Array<Hash>

Transforms the intermediate hash of a row into item data.

Parameters:

  • parsed_row (Hash{Symbol => Hash, Array}) —

    output from Parsing::Parser#parse_row_to_intermediate_hash.

Returns:



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# File 'lib/reading/parsing/transformer.rb', line 34

def transform_intermediate_hash_to_item_hashes(parsed_row)
  if parsed_row[:head].blank?
    raise InvalidHeadError, "Blank or missing Head column"
  end

  template = Config.hash.deep_fetch(:item, :template)

  parsed_row[:head].map.with_index { |_head, head_index|
    template.map { |attribute_name, default_value|
      attribute = attributes.fetch(attribute_name)
      transformed_value = attribute.transform_from_parsed(parsed_row, head_index)

      [attribute_name, transformed_value || default_value]
    }.to_h
    .compact_by(template:)
  }
end