Fix WPS execute outputs parsing assuming string

[fmigneault]

Related Issue / Discussion

When parsing the XML of the WPS execute request (in parse_post_execute):

pywps/pywps/app/WPSRequest.py

Line 280 in 88d2d4d

wpsrequest.outputs = get_output_from_xml(doc)

The outputs that do not provide a mimetype explicitly are defaulted to None:

pywps/pywps/app/WPSRequest.py

Line 590 in 88d2d4d

outpt['mimetype'] = output_el.attrib.get('mimeType', None)

When those output definitions eventually reach the following call, the field mimetype exists and is None, making both the mimetype != '' compare and 'MimeType ' + mimetype + ' not valid' fail (raises cannot concatenate non-string).

pywps/pywps/app/Process.py

Lines 453 to 479 in cd71ee7

	def setup_outputs_from_wps_request(self, wps_request):
	# set as_reference to True for all the outputs specified as reference
	# if the output is not required to be raw
	if not wps_request.raw:
	for wps_outpt in wps_request.outputs:
	is_reference = wps_request.outputs[wps_outpt].get('asReference', 'false')
	mimetype = wps_request.outputs[wps_outpt].get('mimetype', '')
	if is_reference.lower() == 'true':
	# check if store is supported
	if self.store_supported == 'false':
	raise StorageNotSupported(
	'The storage of data is not supported for this process.')
	is_reference = True
	else:
	is_reference = False
	for outpt in self.outputs:
	if outpt.identifier == wps_outpt:
	outpt.as_reference = is_reference
	if isinstance(outpt, ComplexOutput) and mimetype != '':
	data_format = [f for f in outpt.supported_formats if f.mime_type == mimetype]
	if len(data_format) == 0:
	raise InvalidParameterValue(
	'MimeType ' + mimetype + ' not valid')
	outpt.data_format = data_format[0]

This PR simply sets it to the default ''

Additional Information

Contribution Agreement

(as per https://github.com/geopython/pywps/blob/master/CONTRIBUTING.rst#contributions-and-licensing)

• I'd like to contribute [feature X|bugfix Y|docs|something else] to PyWPS. I confirm that my contributions to PyWPS will be compatible with the PyWPS license guidelines at the time of contribution.
• I have already previously agreed to the PyWPS Contributions and Licensing Guidelines

[coveralls]

Coverage remained the same at 0.0% when pulling 9e9dc23 on fmigneault:fix-mimetype-none into 1635529 on geopython:pywps-4.4.

[cehbrecht]

@fmigneault thanks :) Should we do a cherry-pick to bring this to the main branch?

[fmigneault]

@cehbrecht Yes. I believe this will still be an issue in main.