Class: ForestAdminAgent::Utils::CsvGenerator

Inherits:
Object
  • Object
show all
Defined in:
lib/forest_admin_agent/utils/csv_generator.rb

Class Method Summary collapse

Class Method Details

.filter_header(header, requested, kept) ⇒ Object

Labels are positionally aligned with the requested projection, so dropping a field without dropping its label shifts every later value under the wrong heading. The header carries one label per exported column, so a label survives exactly when the projection path at its index did.

A count that does not match the requested projection cannot be mapped onto columns — a to-one relation expanded into several paths, or a polymorphic type field appended — and there is then no header to hand back. Returning the original would leave CsvGeneratorStream.parse_header to check it against the kept count instead, so labels that happen to match the redacted column count would be accepted, printing each surviving column under the label of whatever preceded it. nil is what makes the stream fall back to the field paths.

Handing it back untouched is only safe on the branch above, where nothing was redacted: there the two counts are the same number, so the stream's own check cannot reach a different answer.



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# File 'lib/forest_admin_agent/utils/csv_generator.rb', line 20

def self.filter_header(header, requested, kept)
  return header if header.nil? || kept.size == requested.size

  labels = parse_header_labels(header)

  return nil unless labels&.size == requested.size

  labels.each_with_index
        .select { |_label, index| kept.include?(requested[index]) }
        .map(&:first)
end

.generate(records, projection) ⇒ Object 



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# File 'lib/forest_admin_agent/utils/csv_generator.rb', line 46

def self.generate(records, projection)
  data = {}
  projection.each do |schema_field|
    is_relation = schema_field.include?(':') && projection.relations.key?(schema_field.split(':').first)
    col_name = (is_relation ? schema_field.split(':').first : schema_field)

    data[col_name] = []
    records.each do |row|
      data[col_name] << if is_relation
                          row[col_name]&.[](schema_field.split(':').last)
                        else
                          row[col_name]
                        end
    end
  end

  generate_csv_string(data)
end

.generate_csv_string(data) ⇒ Object

data = { "id" => [1, 2], "email" => ["[email protected]", "[email protected]"], "name" => ["Matthieu", "Nicolas"], }



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# File 'lib/forest_admin_agent/utils/csv_generator.rb', line 70

def self.generate_csv_string(data)
  CSV.generate do |csv|
    # headers
    csv << data.keys

    num_rows = data.values.first.size
    num_rows.times do |i|
      row = data.keys.map { |key| data[key][i] }
      csv << row
    end
  end
end

.parse_header_labels(header) ⇒ Object

The front joins the labels with commas; a JSON array comes from older callers.



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# File 'lib/forest_admin_agent/utils/csv_generator.rb', line 33

def self.parse_header_labels(header)
  return header if header.is_a?(Array)
  return nil unless header.is_a?(String)

  parsed = begin
    JSON.parse(header)
  rescue JSON::ParserError
    nil
  end

  parsed.is_a?(Array) ? parsed : header.split(',', -1)
end