feat(infra): extract rel=alternate feed links from email HTML

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Julien Herr
2026-05-25 17:08:48 +02:00
parent df5546fedd
commit 3c48181c05
2 changed files with 75 additions and 0 deletions
+47
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@@ -4,6 +4,7 @@ import {
extractInlineCids,
htmlToText,
extractLinks,
extractFeedLinks,
} from "./html-processor";
import type { AttachmentData } from "../types";
@@ -348,3 +349,49 @@ describe("extractLinks", () => {
expect(extractLinks("")).toEqual([]);
});
});
describe("extractFeedLinks", () => {
it("extracts rel=alternate links that carry a type", () => {
const html = `<html><head>
<link rel="alternate" type="application/rss+xml" href="https://blog.example.com/feed.xml">
<link rel="alternate" type="application/atom+xml" href="https://blog.example.com/atom.xml">
</head><body>hi</body></html>`;
expect(extractFeedLinks(html)).toEqual([
{
href: "https://blog.example.com/feed.xml",
type: "application/rss+xml",
},
{
href: "https://blog.example.com/atom.xml",
type: "application/atom+xml",
},
]);
});
it("ignores non-alternate rels and links without a type", () => {
const html = `<head>
<link rel="stylesheet" type="text/css" href="https://x.com/a.css">
<link rel="alternate" href="https://x.com/notype">
</head>`;
expect(extractFeedLinks(html)).toEqual([]);
});
it("absolutizes a relative href against the base", () => {
const html = `<head><link rel="alternate" type="application/rss+xml" href="/feed.xml"></head>`;
expect(extractFeedLinks(html, "https://blog.example.com")).toEqual([
{
href: "https://blog.example.com/feed.xml",
type: "application/rss+xml",
},
]);
});
it("drops a relative href when no base is given", () => {
const html = `<head><link rel="alternate" type="application/rss+xml" href="/feed.xml"></head>`;
expect(extractFeedLinks(html)).toEqual([]);
});
it("returns [] for plain-text bodies", () => {
expect(extractFeedLinks("just text https://x.com/feed")).toEqual([]);
});
});
+28
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@@ -69,6 +69,34 @@ export function extractLinks(
return links;
}
// Collect a newsletter's self-advertised feed declarations:
// <link rel="alternate" type="application/(atom|rss)+xml|feed+json" href="…">.
// Returns raw href+type tuples; the domain decides which MIME types are feeds.
// Relative hrefs are absolutized against the sender base (best-effort); only
// http(s) URLs survive. Plain-text bodies have no <link> → [].
export function extractFeedLinks(
content: string,
base = "",
): { href: string; type: string }[] {
if (!content || isPlainText(content)) return [];
const { document } = parseHTML(content);
const links: { href: string; type: string }[] = [];
document
.querySelectorAll('link[rel~="alternate"][type]')
.forEach((el: Element) => {
const type = (el.getAttribute("type") ?? "").trim();
const rawHref = (el.getAttribute("href") ?? "").trim();
if (!type || !rawHref) return;
const href = /^https?:\/\//i.test(rawHref)
? rawHref
: (toAbsolute(rawHref, base) ?? "");
if (!/^https?:\/\//i.test(href)) return;
links.push({ href, type });
});
return links;
}
// Newsletters frequently defer images via data-src/loading="lazy"; readers don't
// run the lazy-loader, so the image renders blank. Promote the real source.
function promoteLazyImages(document: ParsedDocument): void {