diff --git a/server/upstream/upstream.go b/server/upstream/upstream.go
index 5704583..3061a1d 100644
--- a/server/upstream/upstream.go
+++ b/server/upstream/upstream.go
@@ -172,21 +172,7 @@ func (o *Options) Upstream(ctx *context.Context, giteaClient *gitea.Client) (fin
 	}
 
 	// Set ETag & MIME
-	if eTag := header.Get(gitea.ETagHeader); eTag != "" {
-		ctx.RespWriter.Header().Set(gitea.ETagHeader, eTag)
-	}
-	if cacheIndicator := header.Get(gitea.PagesCacheIndicatorHeader); cacheIndicator != "" {
-		ctx.RespWriter.Header().Set(gitea.PagesCacheIndicatorHeader, cacheIndicator)
-	}
-	if length := header.Get(gitea.ContentLengthHeader); length != "" {
-		ctx.RespWriter.Header().Set(gitea.ContentLengthHeader, length)
-	}
-	if mime := header.Get(gitea.ContentTypeHeader); mime == "" || o.ServeRaw {
-		ctx.RespWriter.Header().Set(gitea.ContentTypeHeader, rawMime)
-	} else {
-		ctx.RespWriter.Header().Set(gitea.ContentTypeHeader, mime)
-	}
-	ctx.RespWriter.Header().Set(headerLastModified, o.BranchTimestamp.In(time.UTC).Format(time.RFC1123))
+	setHeader(ctx, header, o.ServeRaw, o.BranchTimestamp)
 
 	log.Debug().Msg("Prepare response")
 
@@ -206,3 +192,22 @@ func (o *Options) Upstream(ctx *context.Context, giteaClient *gitea.Client) (fin
 
 	return true
 }
+
+// setHeader set values to response header
+func setHeader(ctx *context.Context, header http.Header, serveRaw bool, timestap time.Time) {
+	if eTag := header.Get(gitea.ETagHeader); eTag != "" {
+		ctx.RespWriter.Header().Set(gitea.ETagHeader, eTag)
+	}
+	if cacheIndicator := header.Get(gitea.PagesCacheIndicatorHeader); cacheIndicator != "" {
+		ctx.RespWriter.Header().Set(gitea.PagesCacheIndicatorHeader, cacheIndicator)
+	}
+	if length := header.Get(gitea.ContentLengthHeader); length != "" {
+		ctx.RespWriter.Header().Set(gitea.ContentLengthHeader, length)
+	}
+	if mime := header.Get(gitea.ContentTypeHeader); mime == "" || serveRaw {
+		ctx.RespWriter.Header().Set(gitea.ContentTypeHeader, rawMime)
+	} else {
+		ctx.RespWriter.Header().Set(gitea.ContentTypeHeader, mime)
+	}
+	ctx.RespWriter.Header().Set(headerLastModified, timestap.In(time.UTC).Format(time.RFC1123))
+}