From 2378f0fbe732bbad149f82e3267457d1aabee548 Mon Sep 17 00:00:00 2001
From: waiwai <511158080@qq.com>
Date: Wed, 6 May 2026 11:10:14 +0800
Subject: [PATCH] fix: auto-detect Vercel for chat history path

On Vercel, /var/task is read-only at runtime. ChatHistoryPath() now
auto-detects Vercel via IsVercel() and defaults to /tmp/chat_history.json
when no explicit DS2API_CHAT_HISTORY_PATH is set. Manual env var still
works as explicit override.
---
 internal/config/paths.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/internal/config/paths.go b/internal/config/paths.go
index 7b8f22d..60f2829 100644
--- a/internal/config/paths.go
+++ b/internal/config/paths.go
@@ -58,6 +58,11 @@ func RawStreamSampleRoot() string {
 }
 
 func ChatHistoryPath() string {
+	// On Vercel, /var/task is read-only at runtime. If no explicit path is set,
+	// default to /tmp/chat_history.json (the only writable directory).
+	if IsVercel() && strings.TrimSpace(os.Getenv("DS2API_CHAT_HISTORY_PATH")) == "" {
+		return "/tmp/chat_history.json"
+	}
 	return ResolvePath("DS2API_CHAT_HISTORY_PATH", "data/chat_history.json")
 }