RSS integration does not respect trailingSlash configuration option

[njakob]

What version of astro are you using?

2.0.17

Are you using an SSR adapter? If so, which one?

None

What package manager are you using?

npm

What operating system are you using?

Linux

Describe the Bug

While playing with the RSS integration (@astrojs/rss, version 2.1.1), I realized that it always forces trailing slashes even when the trailingSlash option is set to never.

This behavior only applies when the link isn't already a valid URL. However, considering common usages, including examples provided in the documentation, the current implementation forces trailing slashes.

astro/packages/astro-rss/src/index.ts

Lines 184 to 186 in 9d236c9

	const itemLink = isValidURL(result.link)
	? result.link
	: createCanonicalURL(result.link, site).href;

Looking at the documentation, the trailingSlash option should not alter trailing slashes in this case. However, this option is already used in the sitemap integration (@astrojs/sitemap) to alter the behavior of trailing slashes for production builds and is not limited to the dev server as suggested. This has been changed by #4553.

Therefore, for consistency, it would make sense to also apply the same logic to the URLs generated for RSS feeds.

You can observe this in the following minimal reproducible example where adding trailingSlash: 'never' in the configuration affects the sitemap generation but not the RSS feed.

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:news="http://www.google.com/schemas/sitemap-news/0.9" xmlns:xhtml="http://www.w3.org/1999/xhtml" xmlns:image="http://www.google.com/schemas/sitemap-image/1.1" xmlns:video="http://www.google.com/schemas/sitemap-video/1.1">
   <url><loc>https://example.com/</loc></url>
   <url><loc>https://example.com/blog/test</loc></url>
</urlset>

<rss version="2.0">
  <channel>
    <title>Buzz’s Blog</title>
    <description>A humble Astronaut’s guide to the stars</description>
    <link>https://example.com/</link>
    <item>
      <title>Test</title>
      <link>https://example.com/test/</link>
      <guid>https://example.com/test/</guid>
      <pubDate>Sun, 05 Mar 2023 17:53:53 GMT</pubDate>
    </item>
    <item>
      <title>My page of content</title>
      <link>https://example.com/blog/test/</link>
      <guid>https://example.com/blog/test/</guid>
      <pubDate>Sun, 05 Mar 2023 00:00:00 GMT</pubDate>
    </item>
  </channel>
</rss>

Link to Minimal Reproducible Example

https://stackblitz.com/edit/github-l6d4mc

Participation

• I am willing to submit a pull request for this issue.

[matthewp]

The different between the sitemap integration and RSS is that @astrojs/rss is not an integration. So it doesn't have access to your Astro configuration at all. It only knows what you tell it.

So I guess it would make sense to have a trailingSlash option as part of the RSS API. As annoying as that would be to use.

[njakob]

That's an excellent point, I didn't consider that aspect @matthewp

Having this as an option would make sense. However, what would you then expose? Simply having trailingSlash as a boolean since all options (always, never, ignore) might not make sense in this case?

import rss, { pagesGlobToRssItems } from '@astrojs/rss';

export async function get(context) {
  return rss({
    trailingSlash: false,
    title: 'Buzz’s Blog',
    description: 'A humble Astronaut’s guide to the stars',
    site: context.site,
    items: await pagesGlobToRssItems(import.meta.glob('./blog/*.md'))
  });
}

Moreover, it is not possible to access the trailingSlash configuration from the context within the API route, correct?

[matthewp]

boolean sgtm. That's right, you don't have access to the astro config from an API route, so that's why we can't do this automatically.