Can't use all command arguments via the API

[damienalexandre]

We have the ability to set whtmltopdf options via HTTP Header,
but that only works for argument with a value I'm afraid.

HTTP headers are read here:

pydf/docker-entrypoint.py

Lines 39 to 41 in 8f9ce76

	for k, v in request.headers.items():
	if k.startswith('Pdf-') or k.startswith('Pdf_'):
	config[k[4:].lower()] = v.lower()

Then in:

pydf/pydf/wkhtmltopdf.py

Lines 33 to 42 in 8f9ce76

	def _convert_args(**py_args):
	cmd_args = []
	for name, value in py_args.items():
	if value in {None, False}:
	continue
	arg_name = '--' + name.replace('_', '-')
	if value is True:
	cmd_args.append(arg_name)
	else:
	cmd_args.extend([arg_name, str(value)])

The only way to get the argument on the command line is to have a real True.

So via the API we can't get options like --disable-javascript or even --lowquality.

[samuelcolvin]

sorry not to reply earlier. I'd be happy to accept a PR to treat a special value like 'TRUE' or '<set-option> as the same as True and just add the option with no argument.