feat: brand 白名单下发(站点覆盖/租户头像/CORS) + widget/chat 客户端 key 租户化 + 会话站点标

Co-Authored-By: Claude Code <noreply@anthropic.com>

app/engine/routes/chat.py

@@ -48,6 +48,12 @@ async def ws_chat(websocket: WebSocket):
             init_data = await websocket.receive_text()
             init_msg = json.loads(init_data)
 
+            # Task 10: 客户端自报 site(空域名站点如 es 靠嵌入代码 data-site
+            # 接入)记入 client_info 作会话站点标——只加记录,不参与业务逻辑
+            site_slug = str(init_msg.get("site") or "").strip()
+            if site_slug:
+                client_info["site"] = site_slug
+
             if "session_id" in init_msg:
                 conv = await manager.get_by_session(init_msg["session_id"])
                 if conv and conv.status == ConversationStatus.active:

app/engine/routes/chat_rest.py

@@ -47,6 +47,12 @@ async def chat_session(req: SessionRequest, request: Request):
     if xf:
         client_info["ip"] = xf
 
+    # Task 10: ?site=<slug> 记入 client_info 作会话站点标(与 WS init 的
+    # site 字段同语义)——只加记录,不参与业务逻辑
+    site_slug = request.query_params.get("site", "").strip()
+    if site_slug:
+        client_info["site"] = site_slug
+
     # Task 5b: 租户运行时经 state/默认租户兜底解析(过渡期无中间件);
     # manager 由装配线从 runtime 造(db 会话 + runtime 引用)
     runtime = get_runtime(request)

app/engine/routes/public.py

@@ -0,0 +1,84 @@
+"""公开品牌端点(Task 10)——widget/独立页/app 的品牌唯一事实源。
+
+纪律:
+- **显式字段白名单**序列化(BRAND_FIELDS 常量逐字段取值)——绝不序列化
+  整个 site.brand/config:api_key/smtp 等内部字段无出现在响应里的可能
+  (tests/test_brand_endpoint.py 白名单断言钉死);
+- 响应头 ``Access-Control-Allow-Origin: *``:挂件嵌在客户站,brand 与
+  avatar 都是跨源加载;
+- ``?site=<slug>`` 站点覆盖:空域名站点(如 jiancai 的 es)靠嵌入代码
+  ``data-site`` 接入,未知/缺省回退中间件按 Host 解析出的 state.site
+  (即租户默认门面);
+- avatar 按当前租户解析 ``seed_profiles/<slug>/assets/<brand.avatar 文件名>``,
+  文件不存在回退 ``static/kefu-small.png``(两租户头像各归各,字节级不同)。
+
+中间件已保证到达路由的请求必有 state.tenant/state.site;本路由照常经
+中间件(租户域名下访问),经 get_runtime 取运行时。
+"""
+import pathlib
+
+from fastapi import APIRouter, Request
+from fastapi.responses import FileResponse, JSONResponse
+
+from app.engine.config import STATIC_DIR
+from app.engine.routes.runtime import get_runtime
+
+router = APIRouter(prefix="/api/public", tags=["public-brand"])
+
+# 白名单字段(与 tests/test_brand_endpoint.BRAND_EXPECTED 逐字同步):
+# 增删字段必须同时改测试——"绝不多吐"是本端点的红线
+BRAND_FIELDS = ("slug", "title", "color", "avatar", "welcome", "topics",
+                "placeholder", "whatsapp", "email", "privacy_url")
+
+_AVATAR_FALLBACK = STATIC_DIR / "kefu-small.png"
+
+
+def _effective_site(request: Request, runtime):
+    """?site=<slug> 覆盖 state.site(未知 slug 回退),返回 (site, 是否命中覆盖)。"""
+    site_param = (request.query_params.get("site") or "").strip()
+    if not site_param:
+        return request.state.site, False
+    overridden = runtime.site_by_slug(site_param)
+    if overridden is None:
+        return request.state.site, False
+    return overridden, True
+
+
+@router.get("/brand")
+async def brand(request: Request):
+    runtime = get_runtime(request)
+    site, site_hit = _effective_site(request, runtime)
+    b = site.brand
+    payload = {
+        # slug = 租户 slug:客户端据此拼租户化 key(host id / storage key)
+        "slug": runtime.config.slug,
+        "title": b.get("title", ""),
+        "color": b.get("color", ""),
+        # avatar 是本端点的配套 URL(可能带 ?site= 让头像跟随站点覆盖),
+        # 客户端拼 origin 后直接加载
+        "avatar": "/api/public/avatar" + ("?site=" + site.slug if site_hit else ""),
+        "welcome": b.get("welcome", ""),
+        "topics": list(b.get("topics") or []),
+        "placeholder": b.get("placeholder", ""),
+        "whatsapp": b.get("whatsapp", ""),
+        "email": b.get("email", ""),
+        "privacy_url": b.get("privacy_url", ""),
+    }
+    assert set(payload.keys()) == set(BRAND_FIELDS)  # 白名单自检(防手滑加字段)
+    return JSONResponse(payload, headers={"Access-Control-Allow-Origin": "*"})
+
+
+@router.get("/avatar")
+async def avatar(request: Request):
+    runtime = get_runtime(request)
+    site, _ = _effective_site(request, runtime)
+    # 只取文件名(PurePosixPath.name 剥掉一切路径成分)——brand.avatar 是
+    # "/static/kefu-small.png" 这类路径,取基名后拼租户 assets 目录,无路径
+    # 逃逸面(单成分文件名不可能越出 assets/)
+    name = pathlib.PurePosixPath(str(site.brand.get("avatar") or "")).name
+    candidate = runtime.seed_dir / "assets" / name if name else None
+    if candidate is not None and candidate.is_file():
+        return FileResponse(
+            candidate, headers={"Access-Control-Allow-Origin": "*"})
+    return FileResponse(
+        _AVATAR_FALLBACK, headers={"Access-Control-Allow-Origin": "*"})