Class: CsvBuilder::Streamer

Inherits:
Object
  • Object
show all
Defined in:
lib/csv_streamer/template_handler.rb

Instance Method Summary collapse

Constructor Details

#initialize(template_proc) ⇒ Streamer

Returns a new instance of Streamer.



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# File 'lib/csv_streamer/template_handler.rb', line 32

def initialize(template_proc)
  @template_proc = template_proc
end

Instance Method Details

#each ⇒ Object 



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# File 'lib/csv_streamer/template_handler.rb', line 36

def each
  # The ruby csv class will try to infer a separator to use, if the csv options
  # do not set it. ruby's csv calls pos, eof?, read, and rewind to check the first line
  # of the io to infer a separator. Rails' output object does not support these methods
  # so we provide a mock implementation to satisfy csv.
  #
  # See code at https://github.com/ruby/ruby/blob/trunk/lib/csv.rb#L2021 - note that @io points
  # to the output variable defined by this block.
  # output.class.send(:define_method, "pos") {return 0 }
  # output.class.send(:define_method, "eof?") { return true }
  # output.class.send(:define_method, "rewind") {}
  # read needs to return a newline, otherwise csv loops indefinitely looking for the end of the first line.
  # output.class.send(:define_method, "read") {|arg1| return "\\n" }
  # output = ""                                      
  # The ruby csv write method requires output to support << for writing. Here we just 
  # delegate the method call to output's write method.
  # output.class.send(:define_method, "<<") {|arg1| yield arg1}
  
  yielder = CsvBuilder::Yielder.new(Proc.new{|data| yield data})
  csv_stream = CsvBuilder::CSV_LIB.new(yielder, @csv_options || {}) 
  csv = CsvBuilder::TransliteratingFilter.new(csv_stream, @input_encoding || 'UTF-8', @output_encoding || 'LATIN1')
  @template_proc.call(csv)
end