Don’t break NetNewsWire’s footnote detection1.28.1-customcustom

If NetNewsWire detects that a link points to a footnote within the same
post, then tapping on that link will produce a popover displaying the
text of said footnote. Otherwise, it is treated as a regular link and
opened in the default web browser.

Detecting a footnote requires two things:

1. The link URL must consist only of a fragment (i.e. it begins with
   `#`).

2. There must exist another element (typically `<li>`) in the post’s
   HTML with an `id` attribute matching the fragment (that is, the text
   after `#`).

Because FreshRSS’s web frontend can display multiple articles at once,
all relative URLs (including bare fragments) are automatically converted
to absolute URLs at ingestion time, and `id` attributes are replaced
with `data-sanitized-id` attributes. These changes avoid conflicts in
the web UI, but they break NNW’s footnote detection.

Since I use FreshRSS solely as a backend service for NNW (and other
clients), it is reasonable for me to disable those two sanitization
steps in order to take full advantage of NNW’s features.

Remove `id` from the list of attributes to rename, and add it to the
list of allowed attributes for `<li>` elements (as otherwise, it would
be stripped entirely). Convert the `absolutize_url()` function into a
no-op if the relative URL provided appears to be a local fragment.

1 files changed, 2 insertions, 2 deletions

diff --git a/app/Models/SimplePieCustom.php b/app/Models/SimplePieCustom.php
index 44e5b030e..849b23a7b 100644
--- a/app/Models/SimplePieCustom.php
+++ b/app/Models/SimplePieCustom.php
@@ -47,7 +47,7 @@ final class FreshRSS_SimplePieCustom extends \SimplePie\SimplePie
 		$this->set_curl_options($curl_options);
 
 		$this->strip_comments(true);
-		$this->rename_attributes(['id', 'class']);
+		$this->rename_attributes(['class']);
 		$this->allow_aria_attr(true);
 		$this->allow_data_attr(true);
 		$this->allowed_html_attributes([
@@ -121,7 +121,7 @@ final class FreshRSS_SimplePieCustom extends \SimplePie\SimplePie
 			'kbd' => [],
 			'label' => [],
 			'legend' => [],
-			'li' => ['value', 'type'],
+			'li' => ['id', 'value', 'type'],
 			'main' => [],
 			// 'map' => [], // TODO: support <map> after rewriting ids with a format like #ugc-<insert original id here> (maybe)
 			'mark' => [],