Module: JsonCsv::CsvToJson::ClassMethods

Defined in:
lib/json_csv/csv_to_json.rb

Instance Method Summary collapse

Instance Method Details

#apply_field_casting_type(value, field_casting_type) ⇒ Object

Raises:

  • (ArgumentError) 

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# File 'lib/json_csv/csv_to_json.rb', line 70

def apply_field_casting_type(value, field_casting_type)
  raise ArgumentError, "Invalid cast type #{field_casting_type}" unless FIELD_CASTING_TYPES.include?(field_casting_type)

  case field_casting_type
  when TYPE_INTEGER
    raise ArgumentError, "\"#{value}\" is not an integer" unless value =~ /^[0-9]+$/
    value.to_i
  when TYPE_FLOAT
    raise ArgumentError, "\"#{value}\" is not a float" unless value =~ /^[0-9]+(\.[0-9]+)*$/ || value =~ /^\.[0-9]+$/
    value.to_f
  when TYPE_BOOLEAN
    if value.downcase == 'true'
      true
    elsif value.downcase == 'false'
      false
    else
      raise ArgumentError, "\"#{value}\" is not a boolean"
    end
  else
    value # fall back to string, which is the original form
  end
end

#csv_file_to_hierarchical_json_hash(path_to_csv, field_casting_rules = {}, strip_value_whitespace = true) ⇒ Object

Takes flat csv data and yields to a block for each row, presenting that row as un-flattened json. This method works for large CSVs and uses very little memory because it only keeps one row in memory at a time. Sample usage: csv_file_to_hierarchical_json_hash(path_to_csv, field_casting_rules = {}, strip_value_whitespace = true) do |row_json_hash, row_number|


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# File 'lib/json_csv/csv_to_json.rb', line 23

def csv_file_to_hierarchical_json_hash(path_to_csv, field_casting_rules = {}, strip_value_whitespace = true)
  i = 1 # start with row 1 because this corresponds to the first row of 0-indexed CSV data
  CSV.foreach(path_to_csv, headers: true, header_converters: lambda { |header|
    header.strip # remove leading and trailing header whitespace
  }) do |row_data_hash|
    yield csv_row_hash_to_hierarchical_json_hash(row_data_hash, field_casting_rules, strip_value_whitespace), i
    i += 1
  end
end

#csv_row_hash_to_hierarchical_json_hash(row_data_hash, field_casting_rules, strip_value_whitespace = true) ⇒ Object 


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# File 'lib/json_csv/csv_to_json.rb', line 33

def csv_row_hash_to_hierarchical_json_hash(row_data_hash, field_casting_rules, strip_value_whitespace = true)
  hierarchical_hash = {}
  row_data_hash.each do |key, value|
    next if value.nil? || value == '' # ignore nil or empty string values
    put_value_at_json_path(hierarchical_hash, key, value, field_casting_rules)
  end
  # Clean up empty array elements, which may have come about from CSV data
  # that was 1-indexed instead of 0-indexed.
  JsonCsv::Utils.recursively_remove_blank_fields!(hierarchical_hash)
  JsonCsv::Utils.recursively_strip_value_whitespace!(hierarchical_hash) if strip_value_whitespace
  hierarchical_hash
end

#json_path_to_pieces(json_path) ⇒ Object

Takes the given json_path and splits it into individual json path pieces. e.g. Takes “related_books.notes_from_reviewers” and converts it to:

“related_books”, 1, “notes_from_reviewers”, 0

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# File 'lib/json_csv/csv_to_json.rb', line 96

def json_path_to_pieces(json_path)
  # split on...
  # '].' (when preceded by a number)
  # OR
  # '[' (when followed by a number)
  # OR
  # ']' (when preceded by a number)
  # OR
  # '.' (always)
  # ...and remove empty elements (which only come up when you're working with
  # a json_path like '[0]', which splits between the first bracket and the number)
  pieces = json_path.split(/(?<=\d)\]\.|\[(?=\d)|(?<=\d)\]|\./).reject { |piece| piece == '' }
  pieces.map { |piece| piece.to_i.to_s == piece ? piece.to_i : piece } # numeric pieces should be actual numbers
end

#pieces_to_json_path(pieces) ⇒ Object

Generates a string json path from the given pieces e.g. Takes [“related_books”, 1, “notes_from_reviewers”, 0] and converts it to: “related_books.notes_from_reviewers”


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# File 'lib/json_csv/csv_to_json.rb', line 114

def pieces_to_json_path(pieces)
  json_path = ''
  pieces.each do |piece|
    if piece.is_a?(Integer)
      json_path += "[#{piece}]"
    else
      json_path += '.' unless json_path.empty?
      json_path += piece
    end
  end
  json_path
end

#put_value_at_json_path(obj, json_path, value, field_casting_rules = {}, full_json_path_from_top = json_path) ⇒ Object

For the given obj, puts the given value at the given json_path, creating nested elements as needed. This method calls itself recursively when placing a value at a nested path, and during this sequence of calls the obj param may either be a hash or an array.


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# File 'lib/json_csv/csv_to_json.rb', line 50

def put_value_at_json_path(obj, json_path, value, field_casting_rules = {}, full_json_path_from_top = json_path)
  json_path_pieces = json_path_to_pieces(json_path)

  if json_path_pieces.length == 1
    # If the full_json_path_from_top matches one of the field_casting_rules,
    # then case this field to the specified cast type
    full_json_path_from_top_as_field_casting_rule_pattern = real_json_path_to_field_casting_rule_pattern(full_json_path_from_top)
    obj[json_path_pieces[0]] = field_casting_rules.key?(full_json_path_from_top_as_field_casting_rule_pattern) ? apply_field_casting_type(value, field_casting_rules[full_json_path_from_top_as_field_casting_rule_pattern]) : value
  else
    obj[json_path_pieces[0]] ||= (json_path_pieces[1].is_a?(Integer) ? [] : {})
    put_value_at_json_path(obj[json_path_pieces[0]], pieces_to_json_path(json_path_pieces[1..-1]), value, field_casting_rules, full_json_path_from_top)
  end
end

#real_json_path_to_field_casting_rule_pattern(full_json_path_from_top) ⇒ Object

Takes a real json_path like “related_books.notes_from_reviewers” and converts it to a field_casting_rule_pattern like: “related_books.notes_from_reviewers”


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# File 'lib/json_csv/csv_to_json.rb', line 66

def real_json_path_to_field_casting_rule_pattern(full_json_path_from_top)
  full_json_path_from_top.gsub(/\d+/, 'x')
end