fix(aliases): Teach SPA and popovers to handle HTML redirects

This makes aliases work great, because even with the resolution fix
from my previous commit they had no popovers and clicking on alias
links caused a full reload.

quartz/components/scripts/popover.inline.ts

@@ -1,5 +1,6 @@
 import { computePosition, flip, inline, shift } from "@floating-ui/dom"
 import { normalizeRelativeURLs } from "../../util/path"
+import { fetchCanonical } from "./util"
 
 const p = new DOMParser()
 async function mouseEnterHandler(
@@ -37,7 +38,7 @@ async function mouseEnterHandler(
   targetUrl.hash = ""
   targetUrl.search = ""
 
-  const response = await fetch(`${targetUrl}`).catch((err) => {
+  const response = await fetchCanonical(targetUrl).catch((err) => {
     console.error(err)
   })
 

quartz/components/scripts/spa.inline.ts

@@ -1,5 +1,6 @@
 import micromorph from "micromorph"
 import { FullSlug, RelativeURL, getFullSlug, normalizeRelativeURLs } from "../../util/path"
+import { fetchCanonical } from "./util"
 
 // adapted from `micromorph`
 // https://github.com/natemoo-re/micromorph
@@ -45,7 +46,7 @@ window.addCleanup = (fn) => cleanupFns.add(fn)
 let p: DOMParser
 async function navigate(url: URL, isBack: boolean = false) {
   p = p || new DOMParser()
-  const contents = await fetch(`${url}`)
+  const contents = await fetchCanonical(url)
     .then((res) => {
       const contentType = res.headers.get("content-type")
       if (contentType?.startsWith("text/html")) {

quartz/components/scripts/util.ts

@@ -24,3 +24,16 @@ export function removeAllChildren(node: HTMLElement) {
     node.removeChild(node.firstChild)
   }
 }
+
+const canonicalRegex = /<link rel="canonical" href="([^"]*)"/
+
+export async function fetchCanonical(url: URL): Promise<Response> {
+  return fetch(`${url}`).then(async (res) => {
+    if (!res.headers.get("content-type")?.startsWith("text/html")) {
+      return res
+    }
+    const text = await res.clone().text()
+    const [_, redirect] = text.match(canonicalRegex) ?? []
+    return redirect ? fetch(redirect) : res
+  })
+}