Improve caching

static_test.go

@@ -0,0 +1,58 @@
+package main
+
+import (
+	"io/fs"
+	"net/http"
+	"net/http/httptest"
+	"regexp"
+	"testing"
+)
+
+// Every {{asset "…"}} in the templates must name an embedded file, or the page
+// fails to render.
+func TestTemplateAssetsExist(t *testing.T) {
+	ref := regexp.MustCompile(`\{\{asset "([^"]+)"\}\}`)
+	_ = fs.WalkDir(assets, "assets", func(p string, d fs.DirEntry, err error) error {
+		if err != nil || d.IsDir() {
+			return err
+		}
+		b, _ := assets.ReadFile(p)
+		for _, m := range ref.FindAllSubmatch(b, -1) {
+			if _, err := assetURL(string(m[1])); err != nil {
+				t.Errorf("%s: %v", p, err)
+			}
+		}
+		return nil
+	})
+}
+
+func TestServeStaticCaching(t *testing.T) {
+	h := serveStatic()
+	get := func(url, ifNoneMatch string) *httptest.ResponseRecorder {
+		r := httptest.NewRequest(http.MethodGet, url, nil)
+		if ifNoneMatch != "" {
+			r.Header.Set("If-None-Match", ifNoneMatch)
+		}
+		w := httptest.NewRecorder()
+		h.ServeHTTP(w, r)
+		return w
+	}
+	v := assetVersions["style.css"]
+
+	versioned, _ := assetURL("style.css")
+	if w := get(versioned, ""); w.Code != 200 || w.Header().Get("Cache-Control") != "public, max-age=31536000, immutable" {
+		t.Errorf("versioned: %d %q", w.Code, w.Header().Get("Cache-Control"))
+	}
+	for _, u := range []string{"/_/style.css", "/_/style.css?v=stale"} {
+		w := get(u, "")
+		if w.Code != 200 || w.Header().Get("Cache-Control") != "no-cache" || w.Header().Get("ETag") != `"`+v+`"` {
+			t.Errorf("%s: %d %q %q", u, w.Code, w.Header().Get("Cache-Control"), w.Header().Get("ETag"))
+		}
+	}
+	if w := get("/_/style.css", `"`+v+`"`); w.Code != http.StatusNotModified {
+		t.Errorf("revalidate: got %d, want 304", w.Code)
+	}
+	if w := get("/_/fonts/IosevkaSlab.woff2", ""); w.Header().Get("Cache-Control") != "public, max-age=31536000, immutable" {
+		t.Errorf("font: %q", w.Header().Get("Cache-Control"))
+	}
+}