Module: DbMod::As::Csv

Defined in:
lib/db_mod/as/csv.rb

Overview

Coercer which converts an SQL result set into a string formatted as a CSV document. May be enabled for a prepared method or statement method using .as(:csv):

def_statement(:a, 'SELECT a, b FROM foo').as(:csv)
def_prepared(:b, 'SELECT b, c FROM bar').as(:csv)

def do_stuff
  a # => "a,b\r\n1,2\r\n3,4\r\n..."
end

Class Method Summary collapse

Class Method Details

.call(wrapped_method, *args) ⇒ String

Enables this module to be passed to Statements.extend_method as the wrapper function, in which case it will retrieve the results and format them as a CSV document using the column names from the result set.

Parameters:

  • wrapped_method (Method) —

    the method that has been wrapped

  • args (*) —

    arguments expected to be passed to the wrapped method

Returns:

  • (String) —

    a CSV formatted document



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# File 'lib/db_mod/as/csv.rb', line 23

def self.call(wrapped_method, *args)
  results = wrapped_method.call(*args)

  headers = nil
  CSV.generate do |csv|
    results.each do |row|
      csv << (headers = row.keys) unless headers

      csv << headers.map { |col| row[col] }
    end
  end
end