Improve caching

main.go

@@ -2,12 +2,9 @@ package main
 
 import (
 	"context"
-	"crypto/sha256"
 	"embed"
-	"encoding/hex"
 	"flag"
 	"html/template"
-	"io/fs"
 	"log"
 	"net/http"
 	"net/url"
@@ -23,29 +20,14 @@ import (
 //go:embed assets
 var assets embed.FS
 
-// editorBundleVersion is a short content hash of the vendored CodeMirror bundle,
-// appended as ?v=… to its <script> src. The bundle is served immutable under a
-// stable filename, so without this query a rebuilt bundle would never reach a
-// client that already cached the old one (this is the editor cache-bust knob).
-var editorBundleVersion = hashAsset("assets/editor/vendor/codemirror.bundle.js")
-
-func hashAsset(name string) string {
-	b, err := assets.ReadFile(name)
-	if err != nil {
-		return ""
-	}
-	sum := sha256.Sum256(b)
-	return hex.EncodeToString(sum[:])[:12]
-}
-
-// tmplFuncs is shared by every layout-based template: the edit template appends
-// editorBundleVersion to its CodeMirror <script> src to cache-bust the bundle;
-// the layout header renders the maintenance widget.
+// tmplFuncs is shared by every layout-based template: asset links versioned
+// static files (see static.go); the layout header renders the maintenance
+// widget.
 var tmplFuncs = template.FuncMap{
-	"editorBundleVersion": func() string { return editorBundleVersion },
-	"fileIcon":            fileIcon,
-	"icon":                readIcon,
-	"maintenanceWidget":   maintenanceWidget,
+	"asset":             assetURL,
+	"fileIcon":          fileIcon,
+	"icon":              readIcon,
+	"maintenanceWidget": maintenanceWidget,
 }
 
 var (
@@ -137,14 +119,7 @@ func main() {
 	}
 	h := &handler{root: root, user: *user, pass: *pass, authKey: authKey}
 
-	staticFS, _ := fs.Sub(assets, "assets")
-	static := http.StripPrefix("/_/", http.FileServer(http.FS(staticFS)))
-	http.Handle("/_/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if strings.HasPrefix(r.URL.Path, "/_/fonts/") || strings.HasPrefix(r.URL.Path, "/_/editor/vendor/") {
-			w.Header().Set("Cache-Control", "public, max-age=31536000, immutable")
-		}
-		static.ServeHTTP(w, r)
-	}))
+	http.Handle("/_/", serveStatic())
 	http.HandleFunc("/_logout", h.handleLogout)
 	http.HandleFunc("/_reindex", h.handleReindex)
 	http.HandleFunc("/_search", h.handleSearchSuggest)