fix(pgs): dupe headers - pico@66ac6b0

Commit `66ac6b0`

Eric Bower · 2026-04-22 11:00:24 -0400 EDT

parent acf6290

fix(pgs): dupe headers

2 files changed, +29, -11

M cmd/pgs/cdn/main.go

M pkg/httpcache/serve.go

M cmd/pgs/cdn/main.go

+15, -3

......@@ -62,6 +62,14 @@ func newProxyServe(logger *slog.Logger) *proxyServe {
	return &proxyServe{Logger: logger, transport: transport}
}

// Headers that should be stripped from upstream responses because the CDN's
// cache layer will add its own versions.
var stripHeaders = map[string]bool{
	"age":          true,
	"cache-status": true,
	"date":         true,
}

func (p *proxyServe) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	// Dial ash.pgs.sh but keep the original Host header so ash.pgs.sh
	// can route the request to the correct subdomain (zmx.sh, etc.).

......@@ -90,10 +98,13 @@ func (p *proxyServe) ServeHTTP(w http.ResponseWriter, req *http.Request) {
		_ = resp.Body.Close()
	}()

	// Copy headers from upstream, but strip cache-related headers that the
	// CDN's cache layer will regenerate
	for k, vals := range resp.Header {
		for _, v := range vals {
			w.Header().Set(k, v)
		if stripHeaders[strings.ToLower(k)] {
			continue
		}
		w.Header()[k] = vals
	}
	w.WriteHeader(resp.StatusCode)
	_, _ = io.Copy(w, resp.Body)

......@@ -121,11 +132,12 @@ func (c *cachedHttp) ServeHTTP(writer http.ResponseWriter, req *http.Request) {
		if err != nil {
			c.Logger.Error("check request", "err", err)
		}
		writer.WriteHeader(resp.StatusCode)
		defer func() {
			_ = resp.Body.Close()
		}()
		writer.WriteHeader(resp.StatusCode)
		_, _ = io.Copy(writer, resp.Body)
		return
	}

	c.Cache.ServeHTTP(writer, req)

M pkg/httpcache/serve.go

+14, -8

......@@ -95,9 +95,6 @@ func (c *HttpCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
		return
	}

	log.Info("cache miss, requesting upstream", "err", err)
	c.AddCacheMiss()

	// RFC 9111 4.2.4 + 4.3.1/4.3.2: stale must-revalidate entries must be
	// revalidated with conditional headers derived from the stored response.
	// Preserve original client conditional headers so we can evaluate them

......@@ -120,6 +117,8 @@ func (c *HttpCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
		}
	}

	log.Info("cache miss, requesting upstream", "err", err)
	c.AddCacheMiss()
	wrapped := &responseWriter{ResponseWriter: w}
	c.Upstream.ServeHTTP(wrapped, r)
	c.AddUpstreamRequest()

......@@ -128,16 +127,18 @@ func (c *HttpCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	// https://www.rfc-editor.org/rfc/rfc9111.html#section-4.3.4
	// A 304 response updates header metadata but preserves the cached body.
	if wrapped.StatusCode() == http.StatusNotModified {
		log.Info("304 not modified, updating cached headers")
		existingData, exists := c.Cache.Get(cacheKey)
		if !exists {
			// Cache entry vanished; forward the 304 as-is.
			log.Info("no cache entry found, forwarding 304 as-is")
			wrapped.Send()
			return
		}

		var cacheValue CacheValue
		if json.Unmarshal(existingData, &cacheValue) != nil {
		err = json.Unmarshal(existingData, &cacheValue)
		if err != nil {
			log.Error("json unmarshal", "err", err)
			wrapped.Send()
			return
		}

......@@ -153,6 +154,7 @@ func (c *HttpCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
		// Revalidation refreshes the entry -- reset CreatedAt so it's fresh again.
		cacheValue.CreatedAt = time.Now()
		enc, _ := json.Marshal(cacheValue)
		log.Info("updating cached headers from 304 response")
		c.Cache.Remove(cacheKey)
		c.Cache.Add(cacheKey, enc)
		c.AddCacheItem(float64(len(enc)))

......@@ -169,12 +171,14 @@ func (c *HttpCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
				hdr.Set("age", strconv.Itoa(int(ageDur.Seconds())+1))
				hdr.Set("cache-status", cacheStatusStale(cacheKey, wrapped.StatusCode()))
				w.WriteHeader(http.StatusNotModified)
				log.Info("client conditional headers match, returning 304")
				return
			}
		}

		// Client request was unconditional (or conditional but no longer matches)
		// serve the full cached response.
		log.Info("serving full cached response to client")
		serveCache(w, c.Ttl, cacheKey, &cacheValue)
		return
	}

......@@ -215,9 +219,11 @@ func serveCache(w http.ResponseWriter, freshness time.Duration, cacheKey string,
	age := ageDur.Seconds()
	hdr.Set("age", strconv.Itoa(int(age)+1))
	hdr.Set("cache-status", cacheStatusHit(cacheKey, freshness.Seconds()))
	if cacheValue.StatusCode != 0 && cacheValue.StatusCode != http.StatusOK {
		w.WriteHeader(cacheValue.StatusCode)
	statusCode := cacheValue.StatusCode
	if statusCode == 0 {
		statusCode = http.StatusOK
	}
	w.WriteHeader(statusCode)
	_, _ = w.Write(cacheValue.Body)
}

......@@ -741,7 +747,7 @@ func stripForbiddenHeaders(w http.ResponseWriter, cacheValue *CacheValue) http.H
		if isForbiddenHeader(key) {
			continue
		}
		hdr[key] = values
		hdr[http.CanonicalHeaderKey(key)] = values
	}
	return hdr
}

...	...		@@ -121,11 +132,12 @@ func (c cachedHttp) ServeHTTP(writer http.ResponseWriter, req http.Request) {
121	132		if err != nil {
122	133		c.Logger.Error("check request", "err", err)
123	134		}
124		-	writer.WriteHeader(resp.StatusCode)
125	135		defer func() {
126	136		_ = resp.Body.Close()
127	137		}()
	138	+	writer.WriteHeader(resp.StatusCode)
128	139		_, _ = io.Copy(writer, resp.Body)
	140	+	return
129	141		}
130	142
131	143		c.Cache.ServeHTTP(writer, req)

...	...		@@ -128,16 +127,18 @@ func (c HttpCache) ServeHTTP(w http.ResponseWriter, r http.Request) {
128	127		// https://www.rfc-editor.org/rfc/rfc9111.html#section-4.3.4
129	128		// A 304 response updates header metadata but preserves the cached body.
130	129		if wrapped.StatusCode() == http.StatusNotModified {
131		-	log.Info("304 not modified, updating cached headers")
132	130		existingData, exists := c.Cache.Get(cacheKey)
133	131		if !exists {
134	132		// Cache entry vanished; forward the 304 as-is.
	133	+	log.Info("no cache entry found, forwarding 304 as-is")
135	134		wrapped.Send()
136	135		return
137	136		}
138	137
139	138		var cacheValue CacheValue
140		-	if json.Unmarshal(existingData, &cacheValue) != nil {
	139	+	err = json.Unmarshal(existingData, &cacheValue)
	140	+	if err != nil {
	141	+	log.Error("json unmarshal", "err", err)
141	142		wrapped.Send()
142	143		return
143	144		}

...	...		@@ -169,12 +171,14 @@ func (c HttpCache) ServeHTTP(w http.ResponseWriter, r http.Request) {
169	171		hdr.Set("age", strconv.Itoa(int(ageDur.Seconds())+1))
170	172		hdr.Set("cache-status", cacheStatusStale(cacheKey, wrapped.StatusCode()))
171	173		w.WriteHeader(http.StatusNotModified)
	174	+	log.Info("client conditional headers match, returning 304")
172	175		return
173	176		}
174	177		}
175	178
176	179		// Client request was unconditional (or conditional but no longer matches)
177	180		// serve the full cached response.
	181	+	log.Info("serving full cached response to client")
178	182		serveCache(w, c.Ttl, cacheKey, &cacheValue)
179	183		return
180	184		}

...	...		@@ -215,9 +219,11 @@ func serveCache(w http.ResponseWriter, freshness time.Duration, cacheKey string,
215	219		age := ageDur.Seconds()
216	220		hdr.Set("age", strconv.Itoa(int(age)+1))
217	221		hdr.Set("cache-status", cacheStatusHit(cacheKey, freshness.Seconds()))
218		-	if cacheValue.StatusCode != 0 && cacheValue.StatusCode != http.StatusOK {
219		-	w.WriteHeader(cacheValue.StatusCode)
	222	+	statusCode := cacheValue.StatusCode
	223	+	if statusCode == 0 {
	224	+	statusCode = http.StatusOK
220	225		}
	226	+	w.WriteHeader(statusCode)
221	227		_, _ = w.Write(cacheValue.Body)
222	228		}
223	229

...	...		@@ -62,6 +62,14 @@ func newProxyServe(logger slog.Logger) proxyServe {
62	62		return &proxyServe{Logger: logger, transport: transport}
63	63		}
64	64
	65	+	// Headers that should be stripped from upstream responses because the CDN's
	66	+	// cache layer will add its own versions.
	67	+	var stripHeaders = map[string]bool{
	68	+	"age": true,
	69	+	"cache-status": true,
	70	+	"date": true,
	71	+	}
	72	+
65	73		func (p proxyServe) ServeHTTP(w http.ResponseWriter, req http.Request) {
66	74		// Dial ash.pgs.sh but keep the original Host header so ash.pgs.sh
67	75		// can route the request to the correct subdomain (zmx.sh, etc.).

...	...		@@ -90,10 +98,13 @@ func (p proxyServe) ServeHTTP(w http.ResponseWriter, req http.Request) {
90	98		_ = resp.Body.Close()
91	99		}()
92	100
	101	+	// Copy headers from upstream, but strip cache-related headers that the
	102	+	// CDN's cache layer will regenerate
93	103		for k, vals := range resp.Header {
94		-	for _, v := range vals {
95		-	w.Header().Set(k, v)
	104	+	if stripHeaders[strings.ToLower(k)] {
	105	+	continue
96	106		}
	107	+	w.Header()[k] = vals
97	108		}
98	109		w.WriteHeader(resp.StatusCode)
99	110		_, _ = io.Copy(w, resp.Body)

...	...		@@ -95,9 +95,6 @@ func (c HttpCache) ServeHTTP(w http.ResponseWriter, r http.Request) {
95	95		return
96	96		}
97	97
98		-	log.Info("cache miss, requesting upstream", "err", err)
99		-	c.AddCacheMiss()
100		-
101	98		// RFC 9111 4.2.4 + 4.3.1/4.3.2: stale must-revalidate entries must be
102	99		// revalidated with conditional headers derived from the stored response.
103	100		// Preserve original client conditional headers so we can evaluate them

...	...		@@ -120,6 +117,8 @@ func (c HttpCache) ServeHTTP(w http.ResponseWriter, r http.Request) {
120	117		}
121	118		}
122	119
	120	+	log.Info("cache miss, requesting upstream", "err", err)
	121	+	c.AddCacheMiss()
123	122		wrapped := &responseWriter{ResponseWriter: w}
124	123		c.Upstream.ServeHTTP(wrapped, r)
125	124		c.AddUpstreamRequest()

...	...		@@ -153,6 +154,7 @@ func (c HttpCache) ServeHTTP(w http.ResponseWriter, r http.Request) {
153	154		// Revalidation refreshes the entry -- reset CreatedAt so it's fresh again.
154	155		cacheValue.CreatedAt = time.Now()
155	156		enc, _ := json.Marshal(cacheValue)
	157	+	log.Info("updating cached headers from 304 response")
156	158		c.Cache.Remove(cacheKey)
157	159		c.Cache.Add(cacheKey, enc)
158	160		c.AddCacheItem(float64(len(enc)))

...	...		@@ -741,7 +747,7 @@ func stripForbiddenHeaders(w http.ResponseWriter, cacheValue *CacheValue) http.H
741	747		if isForbiddenHeader(key) {
742	748		continue
743	749		}
744		-	hdr[key] = values
	750	+	hdr[http.CanonicalHeaderKey(key)] = values
745	751		}
746	752		return hdr
747	753		}

Commit 66ac6b0

Commit `66ac6b0`