gems/csv_builder/lib/csv_builder/gzip.rb


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# frozen_string_literal: true

module CsvBuilder
  class Gzip < CsvBuilder::Builder
    # Writes the CSV file compressed and yields the written tempfile and rows written.
    #
    #
    # Example:
    # > CsvBuilder::Gzip.new(Issue, { title: -> (row) { row.title.upcase }, id: :id }).render do |tempfile, rows|
    # >   puts tempfile.path
    # >   puts `zcat #{tempfile.path}`
    # >   puts rows
    # > end
    def render
      Tempfile.create(['csv_builder_gzip', '.csv.gz']) do |tempfile|
        Zlib::GzipWriter.open(tempfile.path) do |gz|
          csv = CSV.new(gz)

          write_csv csv, until_condition: -> {} # truncation must be handled outside of the CsvBuilder

          csv.close
        end

        yield tempfile, @rows_written
      end
    end
  end
end