Add a partial to download the assets from CDNs

layouts/partials/dl-asset.html

@@ -0,0 +1,19 @@
+{{/*
+
+  A partial to download an asset from a CDN at build time and serve it from our
+  server. It outputs a string which is the relative path to the asset.
+
+  It accepts a string, which is the URL of the asset to download.
+
+*/}}
+{{- $url := . -}}
+
+{{ with resources.GetRemote $url -}}
+  {{ with .Err -}}
+    {{ errorf "Could not retrieve asset at '%s' from CDN. Reason: %s." $url . -}}
+  {{ else -}}
+    {{ .RelPermalink -}}
+  {{ end -}}
+{{ else -}}
+  {{ errorf "Could not find asset at '%s' on the CDN." $url -}}
+{{ end -}}

layouts/partials/head.html

@@ -26,12 +26,12 @@
 {{ template "_internal/twitter_cards.html" . -}}
 {{ partialCached "head-css.html" . "asdf" -}}
 <script
-  src="{{ "/js/jquery-3.6.3.min.js" | relURL }}"
+  src="{{ partial "dl-asset.html" "https://code.jquery.com/jquery-3.6.3.min.js" }}"
   integrity="sha512-STof4xm1wgkfm7heWqFJVn58Hm3EtS31XFaagaa8VMReCXAkQnJZ+jEy8PCC/iT18dFy95WcExNHFTqLyp72eQ=="
   crossorigin="anonymous"></script>
 {{ if .Site.Params.offlineSearch -}}
 <script defer
-  src="{{ "/js/lunr-2.3.9.min.js" | relURL }}"
+  src="{{ partial "dl-asset.html" "https://unpkg.com/lunr@2.3.9/lunr.min.js" }}"
   integrity="sha384-203J0SNzyqHby3iU6hzvzltrWi/M41wOP5Gu+BiJMz5nwKykbkUx8Kp7iti0Lpli"
   crossorigin="anonymous"></script>
 {{ end -}}
@@ -57,7 +57,7 @@
 {{ define "algolia/head" -}}
 
 {{ if and .Site.Params.search (isset .Site.Params.search "algolia") -}}
-<link rel="stylesheet" href="{{ "/css/docsearch-3.5.2.min.css" | relURL }}"
+<link rel="stylesheet" href="{{ partial "dl-asset.html" "https://cdn.jsdelivr.net/npm/@docsearch/css@3.5.2" }}"
   integrity="sha512-TW5eKlwwg7OfQUVBqxjp94/uqtjJJbhkRE3++XGEQjAL1n3y//QVqS3acPkwqkzInaFRtj+w05uyxDbfDXiI1A=="
   crossorigin="anonymous" />
 {{ end -}}

layouts/partials/scripts.html

@@ -32,7 +32,7 @@
   },
 };
 </script>
-<script src="{{ "/js/markmap-autoloader.js" | relURL }}"></script>
+<script src="{{ partial "dl-asset.html" "https://cdn.jsdelivr.net/npm/markmap-autoloader" }}"></script>
 {{ end -}}
 
 {{ if .Site.Params.plantuml.enable -}}
@@ -41,22 +41,22 @@
 
 {{ if  $needKaTeX -}}
 {{/* load stylesheet and scripts for KaTeX support */ -}}
-<link rel="stylesheet" href="{{ "/css/[email protected]/dist/katex.min.css" | relURL }}"
+<link rel="stylesheet" href="{{ partial "dl-asset.html" "https://cdn.jsdelivr.net/npm/[email protected]/dist/katex.min.css" }}"
       integrity="sha512-mQwom8Ns4op+H29oDkD/LXO/OsXPvCFfkgZkFAVrhhePzRLU8NUI3Nkm43NhWUSmj3p5Cca2HTEkMQmXQRwDQQ==" crossorigin="anonymous">
   {{/* The loading of KaTeX is deferred to speed up page rendering */ -}}
-<script defer src="{{ "/js/[email protected]/dist/katex.min.js" | relURL }}"
+<script defer src="{{ partial "dl-asset.html" "https://cdn.jsdelivr.net/npm/[email protected]/dist/katex.min.js" }}"
         integrity="sha512-sHSNLECRJSK+BFs7E8DiFc6pf6n90bLI85Emiw1jhreduZhK3VXgq9l4kAt9eTIHYAcuQBKHL01QKs4/3Xgl8g=="
         crossorigin="anonymous">
 </script>
   {{ if $needmhchem -}}
   {{/* To add support for displaying chemical equations and physical units, load the mhchem extension: */ -}}
-<script defer src="{{ "/js/[email protected]/dist/contrib/mhchem.min.js" | relURL }}"
+<script defer src="{{ partial "dl-asset.html" "https://cdn.jsdelivr.net/npm/[email protected]/dist/contrib/mhchem.min.js" }}"
         integrity="sha512-V1hl0fnOXW6Cdqe5ZVqtw8TBpJVpu3XRDRQti96j/04+tMarPrCdXEUE3UdfvfKYTpOn9DV4zEZBVr0HhDiuiQ=="
         crossorigin="anonymous">
 </script>
   {{ end -}}
   {{/* To automatically render math in text elements, include the auto-render extension: */ -}}
-<script defer src="{{ "/js/[email protected]/dist/contrib/auto-render.min.js" | relURL }}"
+<script defer src="{{ partial "dl-asset.html" "https://cdn.jsdelivr.net/npm/[email protected]/dist/contrib/auto-render.min.js" }}"
        integrity="sha512-iWiuBS5nt6r60fCz26Nd0Zqe0nbk1ZTIQbl3Kv7kYsX+yKMUFHzjaH2+AnM6vp2Xs+gNmaBAVWJjSmuPw76Efg==" crossorigin="anonymous"
        {{ printf "onload='renderMathInElement(%s, %s);'" (( $.Page.Site.Params.katex.html_dom_element | default "document.body" ) | safeJS ) ( printf "%s" ( $.Page.Site.Params.katex.options | jsonify )) | safeHTMLAttr }}>
 </script>
@@ -78,7 +78,7 @@
 
 {{ if $needmermaid -}}
 {{ $jsArray = $jsArray | append $jsMermaid -}}
-<script src="{{ "/js/mermaid-9.3.0.min.js" | relURL }}" integrity="sha512-ku2nmBrzAXY5YwohzTqLYH1/lvyMrpTVxgQKrvTabd/b/uesqltLORdmpVapYv6QhZVCLUX6wkvFaKOAY4xpUA==" crossorigin="anonymous"></script>
+<script src="{{ partial "dl-asset.html" "https://cdn.jsdelivr.net/npm/mermaid@9.3.0/dist/mermaid.min.js" }}" integrity="sha512-ku2nmBrzAXY5YwohzTqLYH1/lvyMrpTVxgQKrvTabd/b/uesqltLORdmpVapYv6QhZVCLUX6wkvFaKOAY4xpUA==" crossorigin="anonymous"></script>
 {{ end -}}
 
 {{ $js := $jsArray | resources.Concat "js/main.js" -}}
@@ -108,7 +108,7 @@
 {{ partial "hooks/body-end.html" . -}}
 
 {{ define "algolia/scripts" -}}
-<script src="{{ "/js/docsearch-3.5.2.min.js" | relURL }}"
+<script src="{{ partial "dl-asset.html" "https://cdn.jsdelivr.net/npm/@docsearch/js@3.5.2" }}"
   integrity="sha512-LzxWPDNELae1RSIsDRSitKYPJpRtjYo22GbOl+d+xLcjKiZQRRdxSTI3cRRHw7O05e0MbIIu33QnU2rt6ymQ6A=="
   crossorigin="anonymous" ></script>
 <script type="text/javascript">