Add support for shows.acast.com

[PierreMesure]

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What is the purpose of your pull request?

• Bug fix
• Improvement
• New extractor
• New feature

---

Description of your pull request and other information

I tried to add support for Acast's url shows.acast.com. It's my first PR and I wasn't able to check my regex properly so I hope someone more experienced can review it properly. That being said, I tested with the new URLs and it works 🙂.

While testing with the old URLs to ensure no regression, I noticed that some of them are not active anymore: https://www.acast.com/todayinfocus returns a 404.

I didn't remove it as I wasn't sure I should but I'm happy to do a bit of cleaning if someones greenlights it.

I also saw that they are using a new format with a dollar sign for embeds URL but (not being a regex expert) I failed to add it. Here's an example: https://embed.acast.com/$/611233d8767fdf0012f22cb6/611233e4988b6a001394b5cf?feed=true

[dirkf]

Thanks for your work!

I've made a couple of suggestions to fix/improve the regexes (should make the CI tests pass).

For tests that don't work because the page is unavailable, you can add 'skip': 'reason why unavailable', to the test case dict with the info_dict key. If that leaves no valid test page for one of the extraction tactics being tested, a test with a valid page that has the same structure has to be added, or it should be documented in comments that the structure is obsolete.

[PierreMesure]

I committed your suggestions and changed the tests as you asked. Let's see whether there are still any errors.

[dirkf]

These changes, not all related to the current PR, make the download tests pass:

--- PR/youtube-dl/youtube_dl/extractor/acast.py
+++ new/youtube-dl/youtube_dl/extractor/acast.py
@@ -55,16 +55,16 @@
                     '''
     _TESTS = [{
         'url': 'https://www.acast.com/sparpodcast/2.raggarmordet-rosterurdetforflutna',
-        'md5': 'f5598f3ad1e4776fed12ec1407153e4b',
+        'md5': '9904ad5409bbc3b945efc1fe55e5f5d4',
         'info_dict': {
             'id': '2a92b283-1a75-4ad8-8396-499c641de0d9',
             'ext': 'mp3',
             'title': '2. Raggarmordet - Röster ur det förflutna',
-            'description': 'md5:a992ae67f4d98f1c0141598f7bebbf67',
+            'description': r're:(?s)Spår får kontakt med raggarna från 1979\. En titt i arkiven ger oss en gammal förundersökning som någon sparat trots alla bestämmelser om att den bör förstöras\. .{356}\.$',  # md5:a992ae67f4d98f1c0141598f7bebbf67',
             'timestamp': 1477346700,
             'upload_date': '20161024',
             'duration': 2766,
-            'creator': 'Anton Berg & Martin Johnson',
+            'creator': 'Third Ear Studio',
             'series': 'Spår',
             'episode': '2. Raggarmordet - Röster ur det förflutna',
         }
@@ -83,7 +83,7 @@
     }]
 
     def _real_extract(self, url):
-        channel, display_id = re.match(self._VALID_URL, url).groups()
+        channel, display_id = re.match(self._VALID_URL, url).group('channel', 'id')
         episode = self._call_api(
             '%s/episodes/%s' % (channel, display_id),
             display_id, {'showInfo': 'true'})
@@ -106,8 +106,7 @@
         'info_dict': {
             'id': '4efc5294-5385-4847-98bd-519799ce5786',
             'title': 'Today in Focus',
-            'description': 'md5:c09ce28c91002ce4ffce71d6504abaae',
-            'skip': 'Error 404'
+            'description': r're:Hosted by Nosheen Iqbal and Michael Safi, Today in Focus brings you closer to Guardian journalism\. .{994}$',
         },
         'playlist_mincount': 200,
     }, {
@@ -120,7 +119,8 @@
         'url': 'https://play.acast.com/s/getthebeltpod',
         'info_dict': {
             'id': '4caac858-3cda-44e6-b684-50d88b909c18',
-            'title': 'Get The Belt'
+            'title': 'Get The Belt',
+            'description': r'''re:(?s)British Podcast that you probably are not ready for! Join Myles with segments 'such as Myles Measures' that discusses relevant pop culture and society shenanigans,  .{867}$''',
         },
         'playlist_mincount': 138,
     }]
@@ -137,4 +137,4 @@
         for episode in (show.get('episodes') or []):
             entries.append(self._extract_episode(episode, show_info))
         return self.playlist_result(
-            entries, show.get('id'), show.get('title'), show.get('description'))
+            entries, show.get('id'), show.get('title'), clean_html(show.get('description')))

Example:

$ python test/test_download.py TestDownload.test_ACast
[acast] 2.raggarmordet-rosterurdetforflutna: Downloading JSON metadata
[info] Writing video description metadata as JSON to: test_ACast_2a92b283-1a75-4ad8-8396-499c641de0d9.info.json
[debug] Invoking downloader on u'https://sphinx.acast.com/sparpodcast/2.raggarmordet-rosterurdetforflutna/media.mp3?tk=eyJ0ayI6ImRlZmF1bHQiLCJhZHMiOnRydWUsInNwb25zIjp0cnVlLCJzdGF0dXMiOiJwdWJsaWMifQ==&sig=4mClRAB0qh2d8ZixupPWgjm9YxaIJSPcak-ZATQ-H4g'
[download] Destination: test_ACast_2a92b283-1a75-4ad8-8396-499c641de0d9.mp3
[download] 100% of 10.00KiB in 00:00
.
----------------------------------------------------------------------
Ran 1 test in 3.362s

OK
$ 

[dirkf]

For long text fields, the download test proposes a test value expressed as a digest using MD5. Such a test value is accurate and short, but doesn't reveal what changed if the test starts to fail, as happened here.

In the diff I used pattern test values for description. If a test starts to fail, a pattern can be compared with the new value, showing whether there's just been a small change to the value, as when the site starts to append some or different boilerplate, or whether a completely different extraction tactic is needed to get the value correctly.