mix
10c41677bd
test / test (push) Has been cancelled
The assets are baked into the binary, so their FS modification times are the zero value and http.FileServer sent no Last-Modified. With no ETag either, a static response carried no validator at all and the browser was free to guess how long to keep it -- which is how the panel kept showing the previous favicon in the tab well after the new mark was deployed. Hash each asset once at startup and serve that as a strong ETag, with Cache-Control: no-cache so the browser keeps its copy but revalidates. An unchanged asset then costs a bodyless 304 and a changed one is picked up on the next load. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
75 lines
2.6 KiB
Go
75 lines
2.6 KiB
Go
package web
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import (
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"net/http"
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"net/http/httptest"
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"testing"
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)
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// serveStatic runs one GET against the static handler.
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func serveStatic(path string, headers map[string]string) *httptest.ResponseRecorder {
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r := httptest.NewRequest(http.MethodGet, path, nil)
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for k, v := range headers {
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r.Header.Set(k, v)
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}
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rec := httptest.NewRecorder()
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staticHandler().ServeHTTP(rec, r)
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return rec
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}
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// Every embedded asset must carry a validator. The favicon is the one that
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// prompted this: a browser given no ETag and no Last-Modified caches it on a
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// guess, and a rebranded panel keeps serving the old mark from the tab.
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func TestStaticAssetsCarryETag(t *testing.T) {
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for _, name := range []string{"favicon.png", "favicon.svg", "panel.css", "panel.js", "htmx.min.js"} {
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rec := serveStatic("/static/"+name, nil)
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if rec.Code != http.StatusOK {
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t.Fatalf("%s: got status %d, want 200", name, rec.Code)
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}
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if rec.Header().Get("ETag") == "" {
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t.Errorf("%s: no ETag", name)
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}
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if got := rec.Header().Get("Cache-Control"); got != "no-cache" {
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t.Errorf("%s: Cache-Control = %q, want %q", name, got, "no-cache")
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}
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}
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}
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// The point of the ETag is the cheap second request: the browser sends back
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// what it has and gets a bodyless 304 when nothing changed.
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func TestStaticETagRevalidates(t *testing.T) {
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first := serveStatic("/static/favicon.png", nil)
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etag := first.Header().Get("ETag")
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if etag == "" {
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t.Fatal("no ETag on the first response")
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}
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same := serveStatic("/static/favicon.png", map[string]string{"If-None-Match": etag})
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if same.Code != http.StatusNotModified {
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t.Errorf("matching If-None-Match: got status %d, want 304", same.Code)
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}
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if same.Body.Len() != 0 {
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t.Errorf("matching If-None-Match: got %d bytes of body, want none", same.Body.Len())
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}
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// A stale validator — what a browser holds after the asset is replaced —
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// has to produce the new bytes rather than another 304.
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stale := serveStatic("/static/favicon.png", map[string]string{"If-None-Match": `"0000000000000000"`})
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if stale.Code != http.StatusOK {
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t.Errorf("stale If-None-Match: got status %d, want 200", stale.Code)
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}
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if stale.Body.Len() == 0 {
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t.Error("stale If-None-Match: empty body, want the asset")
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}
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}
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// Two different assets must not share a validator, or replacing one would be
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// masked by the other's cached copy.
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func TestStaticETagsAreContentDerived(t *testing.T) {
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png := serveStatic("/static/favicon.png", nil).Header().Get("ETag")
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svg := serveStatic("/static/favicon.svg", nil).Header().Get("ETag")
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if png == svg {
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t.Errorf("favicon.png and favicon.svg share the ETag %s", png)
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}
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}
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