From 4ac2c1c43c5ffe5d96371aeaf02367769fc3034a Mon Sep 17 00:00:00 2001
From: wood chen <wood@czl.net>
Date: Tue, 15 Jul 2025 11:51:56 +0800
Subject: [PATCH] =?UTF-8?q?=E4=B8=BA=E5=9B=BE=E7=89=87=E8=AF=B7=E6=B1=82?=
 =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20Vary=20=E5=A4=B4=E9=83=A8=E6=94=AF?=
 =?UTF-8?q?=E6=8C=81=EF=BC=8C=E4=BB=A5=E4=BE=BF=20CDN=20=E6=A0=B9=E6=8D=AE?=
 =?UTF-8?q?=20Accept=20=E5=A4=B4=E9=83=A8=E8=BF=9B=E8=A1=8C=E7=BC=93?=
 =?UTF-8?q?=E5=AD=98=EF=BC=8C=E4=BC=98=E5=8C=96=E5=93=8D=E5=BA=94=E5=A4=84?=
 =?UTF-8?q?=E7=90=86=E9=80=BB=E8=BE=91=E3=80=82?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 internal/handler/proxy.go | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/internal/handler/proxy.go b/internal/handler/proxy.go
index 325426d..29f2420 100644
--- a/internal/handler/proxy.go
+++ b/internal/handler/proxy.go
@@ -431,6 +431,18 @@ func (h *ProxyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Proxy-Go-AltTarget", "0")
 	}
 
+	// 对于图片请求，添加 Vary 头部以支持 CDN 基于 Accept 头部的缓存
+	if utils.IsImageRequest(r.URL.Path) {
+		// 添加 Vary: Accept 头部，让 CDN 知道响应会根据 Accept 头部变化
+		if existingVary := w.Header().Get("Vary"); existingVary != "" {
+			if !strings.Contains(existingVary, "Accept") {
+				w.Header().Set("Vary", existingVary+", Accept")
+			}
+		} else {
+			w.Header().Set("Vary", "Accept")
+		}
+	}
+
 	// 设置响应状态码
 	w.WriteHeader(resp.StatusCode)