Module: ODSExtractor

Defined in:
lib/ods_extractor.rb,
lib/ods_extractor/version.rb

Defined Under Namespace

Classes: CSVOutput, Error, RowOutput, SAXHandler, SheetFilterHandler

Constant Summary collapse

ACCEPT_ALL_SHEETS_PROC = 
->(_sheet_name) { true }
PROGRESS_HANDLER_PROC = 
->(bytes_read, bytes_remaining) { true }
CHUNK_SIZE = 
32 * 1024
VERSION = 
"0.1.1"

Class Method Summary collapse

Class Method Details

.extract(input_io:, output_handler:, sheet_names: ACCEPT_ALL_SHEETS_PROC, progress_handler_proc: PROGRESS_HANDLER_PROC) ⇒ Object 



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# File 'lib/ods_extractor.rb', line 18

def self.extract(input_io:, output_handler:, sheet_names: ACCEPT_ALL_SHEETS_PROC, progress_handler_proc: PROGRESS_HANDLER_PROC)
  # Feed the XML from the extractor directly to the SAX parser
  entries = ZipKit::FileReader.read_zip_structure(io: input_io)
  contentx_xml_zip_entry = entries.find { |e| e.filename == "content.xml" }

  raise Error, "No `content.xml` found in the ODS file" unless contentx_xml_zip_entry

  sax_handler = ODSExtractor::SAXHandler.new(output_handler)
  sax_filter = ODSExtractor::SheetFilterHandler.new(sax_handler, sheet_names)

  # Because we do not have a random access IO to the deflated XML inside the zip, but
  # we will be reading the deflated bytes and inflating them ourselves, we can't really
  # use the standard Parser - we need to use the PushParser. The Parser "reads" by itself
  # from the IO it has been given, PushParser can be fed bytes as we deflate them.
  push_parser = Nokogiri::XML::SAX::PushParser.new(sax_filter)

  # The "extract" call reads N bytes, inflates them and then returns them. We do not
  # know how big the inflated data will be before we inflate it, and the libxml2
  # push parser will abort with an error if we force-feed it chunks which are too big.
  # So read smol.
  ex = contentx_xml_zip_entry.extractor_from(input_io)
  progress_handler_proc.call(0, contentx_xml_zip_entry.uncompressed_size)
  bytes_read = 0
  until ex.eof?
    chunk = ex.extract(CHUNK_SIZE)
    bytes_read += chunk.bytesize
    progress_handler_proc.call(bytes_read, contentx_xml_zip_entry.uncompressed_size - bytes_read)
    push_parser << chunk
  end
ensure
  push_parser&.finish
end