xml stylesheets do not properly support html features #10166
Description
🐛 bug report
*.xslt files included via <?xml-stylesheet ...?> do not properly support all html features, such as:
- dependencies
- inline scripts/styles
- posthtml minification
- etc.
Also somewhat related, but .xsl and .xslt files cannot be processed directly by parcel. Right now they can only be referenced via <?xml-stylesheet ...?>.
It would be super nice if they could just be processed directly, eg. parcel build file.xslt.
My usecase for this is that my rss feeds are dynamically generated, and I just want to insert a reference to the stylesheet at the top of them.
Sample stylesheet:
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="3.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:atom="http://www.w3.org/2005/Atom">
<xsl:output method="html" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/">
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<meta name="referrer" content="unsafe-url"/>
<title>
<xsl:value-of select="/atom:feed/atom:title"/>
</title>
<link rel="stylesheet" href="/src/assets/scss/water/core.scss"/>
</head>
</html>
</xsl:template>
</xsl:stylesheet>🤔 Expected Behavior
html is properly processed.
Expected output:
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="3.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:atom="http://www.w3.org/2005/Atom">
<xsl:output method="html" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/">
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<meta name="referrer" content="unsafe-url"/>
<title>
<xsl:value-of select="/atom:feed/atom:title"/>
</title>
<link rel="stylesheet" href="file.[hash].css"/>
</head>
</html>
</xsl:template>
</xsl:stylesheet>😯 Current Behavior
html is not properly processed.
Actual output:
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="3.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:atom="http://www.w3.org/2005/Atom">
<xsl:output method="html" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/">
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<meta name="referrer" content="unsafe-url"/>
<title>
<xsl:value-of select="/atom:feed/atom:title"/>
</title>
<link rel="stylesheet" href="/src/assets/scss/water/core.scss"/>
</head>
</html>
</xsl:template>
</xsl:stylesheet>💁 Possible Solution
A solution to this is probably somewhat complicated.
I tried hacking something together myself, however the main issue I ran into was that if I processed the file as if it were html, then all of the xsl-prefixed tags get removed.
🔦 Context
I'm trying to include a stylesheet in rss & atom feeds.
For example, see: https://www.rss.style/
Example feed: https://www.rss.style/example.xml?feedurl=https%3A%2F%2Fnews.ycombinator.com%2Frss
💻 Code Sample
I don't have a full code sample atm, as I'm working in a project with a lot of stuff and it's very late.
I'll provide a full code sample later (remind me if I forget)
🌍 Your Environment
| Software | Version(s) |
|---|---|
| Parcel | 2.15.1 |
| Node | 22.15.0 |
| npm/Yarn | 4.8.1 |
| Operating System | Arch Linux 6.14.4-arch1-2 x86_64 |