Itunes fixes

[Keeper-of-the-Keys]

• Ignore podcasts that are returned without a feedUrl (resolves [Apple] No result if there are multiple podcasts and one of them doesn't contain a feedUrl gpodder-sailfish#225)
• Add pagination support so big result sets can be read

[Keeper-of-the-Keys]

Also all strings were migrated to f-strings

[thp]

See comments.

[thp]

Could be simplified to (note I removed returned_res, because it doesn't seem to be used?):

Suggested change

	if json_data['resultCount'] > 0:
	for entry in json_data['results']:
	if 'feedUrl' not in entry:
	continue
	title = entry['collectionName']
	url = entry['feedUrl']
	image = entry['artworkUrl100']
	yield directory.DirectoryEntry(title, url, image)
	returned_res += 1
	offset += json_data['resultCount']
	else:
	# Unlike the podverse stop condition where we detect a resultCount
	# smaller than the page size for apple we can only stop when 0
	# results are returned because the API seems to consistently
	# return more than the page size and does this in an inconsistent
	# fasion, most often returning 210 results but based on my
	# observartion any number between page size and page size + 10 is
	# possible.
	#
	# With an API that does not obey its own rules the only valid stop
	# condition is no results.
	break
	if json_data['resultCount'] <= 0:
	return
	for entry in json_data['results']:
	if 'feedUrl' not in entry:
	continue
	title = entry['collectionName']
	url = entry['feedUrl']
	image = entry['artworkUrl100']
	yield directory.DirectoryEntry(title, url, image)
	offset += json_data['resultCount']

[thp]

Even if we didn't do it before, we could move those to module-level pre-compiled regular expression objects, and then just use them here.

[Keeper-of-the-Keys]

I don't think that is for the current scope, it is a good idea but figuring that out and reorganizing everything would change this into a monster PR.

[thp]

IMHO it would be fine if this wasn't split into 3 lines, and just a single f-string on one line.

[thp]

See comments.