Module: Metaclean::Qpdf

Defined in:
lib/metaclean/qpdf.rb

Class Method Summary collapse

Class Method Details

.available? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/metaclean/qpdf.rb', line 20

def available?
  return @available if defined?(@available)

  _out, _err, status = Open3.capture3('qpdf', '--version')
  @available = status.success?
rescue Errno::ENOENT
  @available = false
end

.rebuild!(path) ⇒ Object

Rebuilds a PDF in place. The qpdf flags here:

--linearize                          → optimize for streaming/web
--object-streams=generate            → bundle objects efficiently
--remove-unreferenced-resources=yes  → drop unused content (the
                                        privacy-relevant part!)

qpdf can’t write back to the same file, so we use the standard “atomic write” pattern: write to a temp file, then rename it on top of the original. ‘File.rename` (used internally by `FileUtils.mv` for same-filesystem moves) is atomic on POSIX — either the swap completes or nothing changes. No “half-written” state is ever visible.

Raises:



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# File 'lib/metaclean/qpdf.rb', line 51

def rebuild!(path)
  raise Error, 'qpdf not available' unless available?

  # Including `Process.pid` in the temp name avoids collisions if two
  # metaclean processes happen to run at the same time on shared storage.
  tmp = "#{path}.qpdf.tmp.#{Process.pid}"

  _out, err, status = Open3.capture3(
    'qpdf', '--linearize', '--object-streams=generate',
    '--remove-unreferenced-resources=yes', path.to_s, tmp
  )

  # qpdf has a quirk: exit code 3 means "succeeded with warnings" (output
  # is still produced and valid). We treat that the same as success.
  success = status.success? || status.exitstatus == 3
  unless success
    File.delete(tmp) if File.exist?(tmp)
    raise Error, "qpdf failed: #{err.strip}"
  end

  FileUtils.mv(tmp, path.to_s)
  true
end

.version ⇒ Object 



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# File 'lib/metaclean/qpdf.rb', line 29

def version
  return nil unless available?

  out, _err, status = Open3.capture3('qpdf', '--version')
  # `qpdf --version` prints multiple lines starting with the version line.
  # `.lines.first` grabs only that line.
  status.success? ? out.lines.first.to_s.strip : nil
rescue Errno::ENOENT
  nil
end