chore(httpcache): cache-status cleanup and random bug fixes

...	...		@@ -772,11 +772,11 @@ func TestCache304NotModifiedMerge(t *testing.T) {
772	772		resp1, _ := tc.DoWithHeaders(req, map[string][]string{
773	773		"If-None-Match": {"\"abc\""},
774	774		})
775		-	if resp1.StatusCode != http.StatusOK {
776		-	t.Errorf("expected 200 (ETag changed after revalidation), got %d", resp1.StatusCode)
	775	+	if resp1.StatusCode != http.StatusNotModified {
	776	+	t.Errorf("expected 304 (ETag changed after revalidation), got %d", resp1.StatusCode)
777	777		}
778	778		status := resp1.Header.Get("cache-status")
779		-	if !strings.Contains(status, "hit") {
	779	+	if !strings.Contains(status, "fwd=stale") {
780	780		t.Errorf("expected cache-status hit, got %s", status)
781	781		}
782	782

...	...		@@ -2,6 +2,7 @@ package httpcache
2	2
3	3		import (
4	4		"encoding/json"
	5	+	"errors"
5	6		"fmt"
6	7		"log/slog"
7	8		"net/http"

...	...		@@ -12,6 +13,8 @@ import (
12	13		"github.com/hashicorp/golang-lru/v2/expirable"
13	14		)
14	15
	16	+	var ErrMustRevalidate = errors.New("cache is stale and must-revalidate requires revalidation")
	17	+
15	18		type CacheKey interface {
16	19		GetCacheKey(r *http.Request) string
17	20		}

...	...		@@ -99,19 +102,19 @@ func (c HttpCache) ServeHTTP(w http.ResponseWriter, r http.Request) {
99	102		// revalidated with conditional headers derived from the stored response.
100	103		// Preserve original client conditional headers so we can evaluate them
101	104		// after revalidation to decide whether the client gets 304 or 200.
102		-	clientIfNoneMatch := r.Header.Get("If-None-Match")
103		-	clientIfModifiedSince := r.Header.Get("If-Modified-Since")
	105	+	clientIfNoneMatch := r.Header.Get("if-none-match")
	106	+	clientIfModifiedSince := r.Header.Get("if-modified-since")
104	107		clientConditional := clientIfNoneMatch != "" \|\| clientIfModifiedSince != ""
105	108
106		-	if err.Error() == "cache is stale and must-revalidate requires revalidation" {
	109	+	if errors.Is(err, ErrMustRevalidate) {
107	110		if cachedData, exists := c.Cache.Get(cacheKey); exists {
108	111		var cachedValue CacheValue
109	112		if json.Unmarshal(cachedData, &cachedValue) == nil {
110		-	if etag := getHeader(cachedValue.Header, "ETag"); etag != "" {
111		-	r.Header.Set("If-None-Match", etag)
	113	+	if etag := getHeader(cachedValue.Header, "etag"); etag != "" {
	114	+	r.Header.Set("if-none-match", etag)
112	115		}
113		-	if lastMod := getHeader(cachedValue.Header, "Last-Modified"); lastMod != "" {
114		-	r.Header.Set("If-Modified-Since", lastMod)
	116	+	if lastMod := getHeader(cachedValue.Header, "last-modified"); lastMod != "" {
	117	+	r.Header.Set("if-modified-since", lastMod)
115	118		}
116	119		}
117	120		}

...	...		@@ -157,21 +160,15 @@ func (c HttpCache) ServeHTTP(w http.ResponseWriter, r http.Request) {
157	160		if clientConditional {
158	161		// Client sent conditional headers -- re-evaluate against the
159	162		// updated cached entry and return 304 if it still matches.
160		-	r.Header.Set("If-None-Match", clientIfNoneMatch)
161		-	r.Header.Set("If-Modified-Since", clientIfModifiedSince)
162		-	valid, status := c.handleValidation(r, &cacheValue)
	163	+	r.Header.Set("if-none-match", clientIfNoneMatch)
	164	+	r.Header.Set("if-modified-since", clientIfModifiedSince)
	165	+	valid := c.handleValidation(r, &cacheValue)
163	166		if valid {
164		-	hdr := w.Header()
165		-	for key, values := range cacheValue.Header {
166		-	if isForbiddenHeader(key) {
167		-	continue
168		-	}
169		-	hdr[key] = values
170		-	}
	167	+	hdr := stripForbiddenHeaders(w, &cacheValue)
171	168		ageDur := calcAge(cacheValue.CreatedAt)
172	169		hdr.Set("age", strconv.Itoa(int(ageDur.Seconds())+1))
173		-	hdr.Set("cache-status", cacheStatusHit(cacheKey, c.Ttl.Seconds()))
174		-	w.WriteHeader(status)
	170	+	hdr.Set("cache-status", cacheStatusStale(cacheKey, wrapped.StatusCode()))
	171	+	w.WriteHeader(http.StatusNotModified)
175	172		return
176	173		}
177	174		}

...	...		@@ -213,15 +210,7 @@ func isForbiddenHeader(key string) bool {
213	210		}
214	211
215	212		func serveCache(w http.ResponseWriter, freshness time.Duration, cacheKey string, cacheValue *CacheValue) {
216		-	hdr := w.Header()
217		-	for key, values := range cacheValue.Header {
218		-	// RFC 9111 3.1 - Skip forbidden headers
219		-	if isForbiddenHeader(key) {
220		-	continue
221		-	}
222		-	hdr[key] = values
223		-	}
224		-
	213	+	hdr := stripForbiddenHeaders(w, cacheValue)
225	214		ageDur := calcAge(cacheValue.CreatedAt)
226	215		age := ageDur.Seconds()
227	216		hdr.Set("age", strconv.Itoa(int(age)+1))

...	...		@@ -293,30 +282,12 @@ func getHeader(headers map[string][]string, key string) string {
293	282		// handleValidation handles conditional request validation.
294	283		// RFC 9110 13 Conditional Requests.
295	284		// RFC 9111 4.3.2 Response Validation.
296		-	func (c HttpCache) handleValidation(r http.Request, cacheValue *CacheValue) (bool, int) {
297		-	// Get ETag and Last-Modified with case-insensitive lookup
298		-	var etag string
299		-	var lastModified string
300		-	for key, values := range cacheValue.Header {
301		-	lowerKey := strings.ToLower(key)
302		-	c.Logger.Debug(
303		-	"validate",
304		-	"key", key,
305		-	"lowerKey", lowerKey,
306		-	"values", values,
307		-	"etag", etag,
308		-	"lastModified", lastModified,
309		-	)
310		-	if lowerKey == "etag" && len(values) > 0 {
311		-	etag = values[0]
312		-	}
313		-	if lowerKey == "last-modified" && len(values) > 0 {
314		-	lastModified = values[0]
315		-	}
316		-	}
	285	+	func (c HttpCache) handleValidation(r http.Request, cacheValue *CacheValue) bool {
	286	+	etag := getHeader(cacheValue.Header, "etag")
	287	+	lastModified := getHeader(cacheValue.Header, "last-modified")
317	288
318	289		c.Logger.Debug(
319		-	"validate result",
	290	+	"validate",
320	291		"etag", etag,
321	292		"lastModified", lastModified,
322	293		)

...	...		@@ -327,20 +298,17 @@ func (c HttpCache) handleValidation(r http.Request, cacheValue *CacheValue) (b
327	298		if ifNoneMatch != "" {
328	299		// Wildcard If-None-Match: *
329	300		if ifNoneMatch == "*" {
330		-	if etag != "" {
331		-	return true, http.StatusNotModified
332		-	}
333		-	return false, 0
	301	+	return etag != ""
334	302		}
335	303
336	304		// Check if any of the provided ETags match
337	305		etags := parseETags(ifNoneMatch)
338	306		for _, etagVal := range etags {
339	307		if etagVal == etag {
340		-	return true, http.StatusNotModified
	308	+	return true
341	309		}
342	310		}
343		-	return false, 0
	311	+	return false
344	312		}
345	313
346	314		// RFC 9110 13.1.3 If-Modified-Since

...	...		@@ -352,7 +320,7 @@ func (c HttpCache) handleValidation(r http.Request, cacheValue *CacheValue) (b
352	320		cachedTime := parseTimeFallback(lastModified)
353	321		if !cachedTime.IsZero() {
354	322		if !cachedTime.After(reqTime) {
355		-	return true, http.StatusNotModified
	323	+	return true
356	324		}
357	325		}
358	326		}

...	...		@@ -371,13 +339,13 @@ func (c HttpCache) handleValidation(r http.Request, cacheValue *CacheValue) (b
371	339		// Cached response is not modified since the request time
372	340		// We can serve from cache, but don't return 304
373	341		// The caller will handle the cache hit
374		-	return false, 0
	342	+	return false
375	343		}
376	344		}
377	345		}
378	346		}
379	347
380		-	return false, 0
	348	+	return false
381	349		}
382	350
383	351		func parseETags(etags string) []string {

...	...		@@ -628,7 +596,7 @@ func (c HttpCache) maybeUseCache(cacheKey string, w http.ResponseWriter, r htt
628	596		age := calcAge(cacheValue.CreatedAt)
629	597		freshness := calcFreshness(cacheContState, expires, age, c.Ttl)
630	598		if freshness <= 0 {
631		-	return fmt.Errorf("cache is stale and must-revalidate requires revalidation")
	599	+	return ErrMustRevalidate
632	600		}
633	601		}
634	602

...	...		@@ -640,32 +608,22 @@ func (c HttpCache) maybeUseCache(cacheKey string, w http.ResponseWriter, r htt
640	608		return fmt.Errorf("cache has no-store")
641	609		}
642	610
	611	+	age := calcAge(cacheValue.CreatedAt)
	612	+	freshness := calcFreshness(cacheContState, expires, age, c.Ttl)
	613	+
643	614		// RFC 9111 4.3 Validation - check validation headers first
644	615		// RFC 9110 13 Conditional Requests
645	616		// https://www.rfc-editor.org/rfc/rfc9110.html#section-13
646		-	valid, status := c.handleValidation(r, &cacheValue)
	617	+	valid := c.handleValidation(r, &cacheValue)
647	618		if valid {
648		-	// RFC 9111 4.3.4 304 Not Modified
649		-	// https://www.rfc-editor.org/rfc/rfc9111.html#section-4.3.4
650		-	// A 304 response must include headers the client needs to update
651		-	// its cached representation (ETag, Last-Modified, Cache-Control, etc.)
652		-	hdr := w.Header()
653		-	for key, values := range cacheValue.Header {
654		-	if isForbiddenHeader(key) {
655		-	continue
656		-	}
657		-	hdr[key] = values
658		-	}
	619	+	hdr := stripForbiddenHeaders(w, &cacheValue)
659	620		ageDur := calcAge(cacheValue.CreatedAt)
660	621		hdr.Set("age", strconv.Itoa(int(ageDur.Seconds())+1))
661		-	hdr.Set("cache-status", cacheStatusHit(cacheKey, c.Ttl.Seconds()))
662		-	w.WriteHeader(status)
	622	+	hdr.Set("cache-status", cacheStatusHit(cacheKey, freshness.Seconds()))
	623	+	w.WriteHeader(http.StatusNotModified)
663	624		return nil
664	625		}
665	626
666		-	age := calcAge(cacheValue.CreatedAt)
667		-	freshness := calcFreshness(cacheContState, expires, age, c.Ttl)
668		-
669	627		// Check if request allows stale responses (max-stale)
670	628		// RFC 9111 5.2.1.2 - max-stale allows serving stale responses
671	629		// We need to check this before the freshness <= 0 check

...	...		@@ -758,6 +716,10 @@ func cacheStatusHit(cacheKey string, ttl float64) string {
758	716		return fmt.Sprintf("pico; hit; ttl=%d; key=%s", int(ttl), cacheKey)
759	717		}
760	718
	719	+	func cacheStatusStale(cacheKey string, originStatus int) string {
	720	+	return fmt.Sprintf("pico; fwd=stale; fwd-status=%d", originStatus)
	721	+	}
	722	+
761	723		func cacheStatusMiss(cacheKey string, stored bool) string {
762	724		// RFC 9211 2.2 Cache-Status fwd
763	725		// https://www.rfc-editor.org/rfc/rfc9211#section-2.2

...	...		@@ -772,3 +734,14 @@ func cacheStatusMiss(cacheKey string, stored bool) string {
772	734		status = fmt.Sprintf("%s; key=%s", status, cacheKey)
773	735		return status
774	736		}
	737	+
	738	+	func stripForbiddenHeaders(w http.ResponseWriter, cacheValue *CacheValue) http.Header {
	739	+	hdr := w.Header()
	740	+	for key, values := range cacheValue.Header {
	741	+	if isForbiddenHeader(key) {
	742	+	continue
	743	+	}
	744	+	hdr[key] = values
	745	+	}
	746	+	return hdr
	747	+	}

Commit f46c23c

Commit `f46c23c`