execute_process is not able to respond async if job output media type is different from application/json

[ricardogsilva]

It is currently not possible to have a process that operates in async mode and generates an output with a media type that is not JSON.

As per this section of the execute_process API handler:

pygeoapi/pygeoapi/api/processes.py

Lines 523 to 540 in 08031d4

	if mime_type == 'application/json':
	if requested_response == 'document':
	pretty_print_ = api.pretty_print
	else: # raw
	pretty_print_ = False
	response2 = to_json(response, pretty_print_)
	else:
	response2 = response
	if (headers.get('Preference-Applied', '') == RequestedProcessExecutionMode.respond_async.value): # noqa
	LOGGER.debug('Asynchronous mode detected, returning statusInfo')
	response2 = {
	'jobID': job_id,
	'type': 'process',
	'status': status.value
	}
	response2 = to_json(response2, pretty_print_)

It can be observed that:

• When the if mime_type == "application/json" condition is False (line 530), the pretty_print_ variable is never created.
• Regardless, this variable is accessed later (line 540) if the processor is executing in async mode. This causes this error:

  File "/home/ricardo/dev/pygeoapi/pygeoapi/api/processes.py", line 540, in execute_process
    response2 = to_json(response2, pretty_print_)
                                   ^^^^^^^^^^^^^
UnboundLocalError: cannot access local variable 'pretty_print_' where it is not associated with a value

@tomkralidis this seems to be a regression introduced in 0b53d49 like #2304