benecaster_feed_enclosure_url

Filters the audio or video URL placed in the RSS enclosure tag for each episode. Use to route downloads through a custom proxy, or append tracking parameters where you need $show_id. Fires after benecaster_episode_audio_url — prefer that hook for URL substitution; use this one for proxy-routing or parameter-appending.

Core registers two callbacks at priority 10. Analytics\ProxyUrlRewriter swaps in the download proxy (/benecaster-download/{id}/?token={TOKEN}) on non-public tiers when download tracking is on for the episode. Feed\EnclosureUrlPrefixer joins the show’s Enclosure URL prefix (Show Settings → Feeds), dropping the URL’s leading https:// and keeping http://, and passes an already-proxied URL through untouched. Their result does not depend on which runs first: if the prefixer runs first, the rewriter replaces the prefixed URL wholesale with the proxy URL; if the rewriter runs first, the prefixer recognises the result as a proxy URL and leaves it alone. A callback registered at priority > 10 sees the final URL — prefixed, proxied, or both in whichever combination core produced.

⚠ Never wrap a proxy URL in a third-party prefix. Its ?token={TOKEN} is the subscriber’s private-feed credential; wrapping it would put that token in the tracking service’s own logs. Check for home_url( '/benecaster-download/' ) before prefixing, the way core’s own prefixer does.

The same value is also accessible through benecaster_feed_episode_data as the enclosure_url key — use this dedicated filter when you only need the URL and want to avoid receiving the full episode data array. The returned URL must always be a valid, non-empty URL.

It fires in two places, not one. Per item, where the result goes into enclosure url="..."; and again when building each channel-level <podcast:trailer>, with that trailer episode’s ID. Both of core’s own callbacks run in both places.

Two practical consequences. A prefix or proxy sees the trailer URL rewritten too, which is usually what you want. And a callback that counts its own invocations fires once per item plus once per trailer, not once per item.

For routing every enclosure through a measurement or CDN prefix service (Podtrac, OP3, Podscribe), use Show Settings → Feeds → Enclosure URL prefix instead of this filter — no code needed for that case.

<?php
add_filter( 'benecaster_feed_enclosure_url', function (
    string $url,
    int    $episode_id,
    int    $show_id,
    string $tier_slug
): string {
    $outer = 'https://op3.dev/e/';
    if ( '' === $url || str_starts_with( $url, $outer ) ) {
        return $url;
    }
    // Never wrap the download proxy URL: it carries the subscriber's feed token.
    if ( str_starts_with( $url, home_url( '/benecaster-download/' ) ) ) {
        return $url;
    }
    return $outer . preg_replace( '#^https://#i', '', $url );
}, 20, 4 );