Enclosure can't deal with CDN media files - WPCore redirects the URL

[researcher]

When using WP as audio collection, RSS2 is needed to get podcasts spread around f.i. to iTunes ect.

To validate the feed right from WP 4.9.6 at ​http://www.feedvalidator.org from source ​https://ferrie.audio/cat/podcasts/feed/ we recieve several errors where the most important one is the redirection of CDN URL's to WP URL

example: cdn.ferrie.audio/blablabla/Can-You-hear-Me.m4a - the CDN.(= AWS3) location of the file
becomes: ferrie.audio/blablabla/Can-You-hear-Me.m4a

without the CDN. urlprefix there is no audio stream - all streams are at CDN.
adding the CDN. urlprefix enclosure by hand and then save the blogpost results is 2 enclosures - 1 with CDN. - 1 without
adding the enclosure but NOT save the blogpost shows the correct enclosure - but - the RSS output shows the URL without the CDN. urlprefix

have been looking into the /wp-includes/feed.php - but there is for me no place to find where this redirection takes place - an feed expert might be able to correct this problem - sorry that i can't - i'm no coder i make music.

[stevenkword]

Hi @researcher,

Thank you for the report. Can you tell us more about what you are using as a CDN solution. Based off what I know at the time, I suspect the author of the CDN integration did not add in the appropriate filters for feeds.

​https://developer.wordpress.org/reference/functions/rss_enclosure/

[researcher]

hi Steven,

as CDN i use Amazon S3 - - bucket name cdn.ferrie.audio

audio inserted into the blogpost: [audio m4a="​https://cdn.ferrie.audio/blablabla/wp-content/uploads/year/monthe/more-nubers-here/Summer_Rain.m4a"][/audio]

enclosure to the blogpost is slightly different: ​https://ferrie.audio/blablabla/wp-content/uploads/year/month/Summer_Rain.m4a

RSS feeds of my subdomain podcast.ferrie.audio are accepted by iTunes - url is ​https://podcastsconnect.apple.com/my-podcasts/ferries-podcasts/1393680623

if you need more details - please let me know