Re-enable validation checker as an option and refactor as separate file and function.

[jameshalgren]

This is a proposal to move the validation checking capability to a separate file. Moving this to a separate file would reduce the tqdm dependency, which is only needed if validation is requested.

A use case we might want to support is providing an externally generated list of files to this utility to check if the URLs have downloadable endpoints.

nwmurl/nwmurl/urlgennwm.py

Lines 13 to 46 in aadafa3

	from tqdm import tqdm
	# def check_valid_urls(file_list, session=None):
	# """if not session:
	# session = requests.Session()"""
	# t = tqdm(range(len(file_list)))
	# check_url_part = partial(check_url, t)
	# """with ThreadPoolExecutor(max_workers=10) as executor:
	# valid_file_list = list(executor.map(check_url_part, file_list))"""
	# valid_file_list = [gevent.spawn(check_url_part, file_name) for file_name in file_list]
	# gevent.joinall(valid_file_list)
	# return [file.get() for file in valid_file_list if file.get() is not None]
	# def check_url(t, file):
	# filename = file.split("/")[-1]
	# try:
	# with requests.head(file) as response:
	# if response.status_code == 200:
	# t.set_description(f"Found: {filename}")
	# t.update(1)
	# t.refresh()
	# return file
	# else:
	# t.set_description(f"Not Found: {filename}")
	# t.update(1)
	# t.refresh()
	# return None
	# #response = session.head(file, timeout=1)
	# except requests.exceptions.RequestException:
	# t.set_description(f"Not Found: {filename}")
	# t.update(1)
	# t.refresh()
	# return None