how to get headers from a CSV file in ruby

Question

I need to validate headers in a CSV file before parsing data in it.

# convert the data into an array of hashes
CSV::Converters[:blank_to_nil] = lambda do |field|
  field && field.empty? ? nil : field
end
csv = CSV.new(file, :headers => true, :header_converters => :symbol, :converters => [:all, :blank_to_nil])
csv_data = csv.to_a.map {|row| row.to_hash }

I know I can use headers method to get the headers

    headers = csv.headers

But the problem with headers method is it "Returns nil if headers will not be used, true if they will but have not yet been read, or the actual headers after they have been read."

So if I put headers = csv.headers above csv_data = csv.to_a.map {|row| row.to_hash } line headers is true and if I put it after reading data, headers contain headers row in an array. It imposes an order of instructions on my method which is very hard to test and is bad programming.

Is there a way to read headers row without imposing order in this scenario? I'm using ruby 2.0.

Answer 1

CSV.open(file_path, &:readline)