diff --git a/asset/asset_test.go b/asset/asset_test.go
index 672cc64..d347111 100644
--- a/asset/asset_test.go
+++ b/asset/asset_test.go
@@ -69,6 +69,7 @@ body { background: url(../img/bg.png); }
const htmlDoc = `
+
@@ -98,6 +99,7 @@ func TestRewriteHTML(t *testing.T) {
checks := map[string]bool{
`href="_kage/ex.com/css/main.css"`: true, // stylesheet localised
+ `href="_kage/ex.com/css/vp.css"`: true, // multi-value "preload stylesheet" rel localised
`href="_kage/ex.com/favicon.ico"`: true, // icon localised
`href="https://ex.com/canon"`: true, // canonical left alone
`href="docs/intro/index.html"`: true, // internal page → local
diff --git a/asset/html.go b/asset/html.go
index d939327..ddbe040 100644
--- a/asset/html.go
+++ b/asset/html.go
@@ -9,13 +9,28 @@ import (
"golang.org/x/net/html/atom"
)
-// stylesheetRels are values whose href kage downloads as an asset.
-var stylesheetRels = map[string]bool{
- "stylesheet": true, "icon": true, "shortcut icon": true,
+// assetRels are the individual tokens whose href kage downloads as
+// an asset. A rel attribute is a space-separated token list, so a single known
+// token in it (for example the "stylesheet" in "preload stylesheet") is enough.
+var assetRels = map[string]bool{
+ "stylesheet": true, "icon": true,
"apple-touch-icon": true, "apple-touch-icon-precomposed": true,
"mask-icon": true, "manifest": true, "preload": true, "prefetch": true,
}
+// linkRelDownloadable reports whether a names a resource kage should
+// download. It treats rel as the space-separated token list the HTML spec
+// defines, so "preload stylesheet", "shortcut icon", or a bare "stylesheet" all
+// match on a single recognised token.
+func linkRelDownloadable(rel string) bool {
+ for _, tok := range strings.Fields(strings.ToLower(rel)) {
+ if assetRels[tok] {
+ return true
+ }
+ }
+ return false
+}
+
// RewriteHTML walks the parsed document and rewrites every resource and link
// reference through sink, resolving relative URLs against base. It mutates the
// tree in place; the caller renders it afterwards. References kage cannot handle
@@ -40,8 +55,7 @@ func rewriteElement(n *html.Node, base *url.URL, sink RefSink) {
case atom.Iframe, atom.Frame:
rewriteAttr(n, "src", base, sink, pageOrAsset)
case atom.Link:
- rel := strings.ToLower(strings.TrimSpace(attrVal(n, "rel")))
- if stylesheetRels[rel] {
+ if linkRelDownloadable(attrVal(n, "rel")) {
rewriteAttr(n, "href", base, sink, alwaysAsset)
}
case atom.Img: