fix hls

backend/.env.example

@@ -89,12 +89,10 @@ POSTGRES_PORT=45432
 # 链路 2（模拟实时）与链路 3（离线 batch）需开启；链路 1 真 RTSP 开录不依赖此项
 # DEMO_ORCHESTRATOR_ENABLED=false
 # DEMO_ORCHESTRATOR_RTSP_PORT=18554
-# 联调台 HLS 预览（推荐 Compose 侧车 mediamtx-hls，API 只反代）
-# DEMO_HLS_PREVIEW_UPSTREAM=http://mediamtx-hls:8888
-# DEMO_HLS_PREVIEW_CONFIG_DIR=/hls-preview-config
-# 本机无 Compose 时：留空 upstream，临时 docker 容器 + 端口 18888
+# 联调台 HLS（Compose：先 docker compose up -d mediamtx-hls api）
+# DEMO_HLS_PREVIEW_UPSTREAM=http://127.0.0.1:18888
+# 本机 uvicorn 且无 mediamtx-hls 侧车时改为：DEMO_HLS_PREVIEW_UPSTREAM=ephemeral
 # DEMO_HLS_PREVIEW_PORT=18888
-# DEMO_HLS_PREVIEW_HOST=127.0.0.1
 # Docker 内 API 访问宿主机假流时写入站点 JSON 的主机名（默认 host.docker.internal）
 # DOCKER_DEMO_ORCHESTRATOR_RTSP_JSON_HOST=host.docker.internal
 # 链路 2 simulated-start / fake_rtsp_from_file 起 MediaMTX 容器用

backend/app/api.py

@@ -158,7 +158,15 @@ async def recording_modes_status() -> dict:
         "orchestrator_rtsp_port": settings.demo_orchestrator_rtsp_port,
         "orchestrator_rtsp_json_host": settings.demo_orchestrator_rtsp_json_host,
         "hls_preview_port": settings.demo_hls_preview_port,
-        "hls_preview_upstream": (settings.demo_hls_preview_upstream or "").strip() or None,
+        "hls_preview_upstream": HlsPreviewManager.resolve_upstream_setting(
+            settings.demo_hls_preview_upstream
+        )
+        or None,
+        "hls_preview_mode": (
+            "attached"
+            if HlsPreviewManager.resolve_upstream_setting(settings.demo_hls_preview_upstream)
+            else "ephemeral"
+        ),
     }
 
 
@@ -212,7 +220,7 @@ async def hls_preview_ensure(
             detail="OR_SITE_CONFIG_JSON_FILE is not set",
         )
     hls_port = int(settings.demo_hls_preview_port)
-    upstream_url = (settings.demo_hls_preview_upstream or "").strip()
+    upstream_url = settings.demo_hls_preview_upstream
 
     resolver = BackendResolver(settings, hikvision_runtime=None)
     sources: dict[str, str] = {}
@@ -247,9 +255,16 @@ async def hls_preview_ensure(
         await asyncio.to_thread(_start)
     except Exception as exc:
         logger.exception("HLS preview start failed: {}", exc)
+        detail = f"HLS preview start failed: {exc}"
+        if "host.docker.internal" in str(exc) and "Invalid ip address" in str(exc):
+            detail += (
+                "。当前 API 可能仍是旧版本：请执行 "
+                "`docker compose up -d --build api mediamtx-hls`，并确认 "
+                "DEMO_HLS_PREVIEW_UPSTREAM=http://127.0.0.1:18888（勿把 host.docker.internal 用于 docker -p）。"
+            )
         raise HTTPException(
             status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
-            detail=f"HLS preview start failed: {exc}",
+            detail=detail,
         ) from exc
 
     sess = HlsPreviewManager.active()

backend/app/config.py

@@ -189,10 +189,10 @@ class Settings(BaseSettings):
     demo_orchestrator_rtsp_json_host: str = "host.docker.internal"
     demo_hls_preview_port: int = Field(default=18888, ge=1, le=65535)
     demo_hls_preview_upstream: str = Field(
-        default="",
+        default="http://127.0.0.1:18888",
         description=(
-            "推荐：Compose 内 MediaMTX 基址，如 http://mediamtx-hls:8888。"
-            "设此项后 API 不再 docker run -p，只写配置并重启 mediamtx-hls。"
+            "MediaMTX HLS 基址（Compose 侧车默认 127.0.0.1:18888）。"
+            "设为 ephemeral 则改回临时 docker run（本机开发）。"
         ),
     )
     demo_hls_preview_config_dir: str = Field(

backend/app/services/hls_preview.py

@@ -151,6 +151,14 @@ class HlsPreviewManager:
             shutil.rmtree(sess.config_dir, ignore_errors=True)
         cls._active = None
 
+    @classmethod
+    def resolve_upstream_setting(cls, upstream_url: str) -> str:
+        """``ephemeral`` / 空 → 临时容器；否则走 Compose 侧车（写配置 + restart）。"""
+        raw = (upstream_url or "").strip()
+        if raw.lower() in ("ephemeral", "none", "off"):
+            return ""
+        return raw
+
     @classmethod
     def start(
         cls,
@@ -163,10 +171,11 @@ class HlsPreviewManager:
         ephemeral_port: int = 18888,
         ready_timeout_sec: float = 30.0,
     ) -> HlsPreviewSession:
-        if (upstream_url or "").strip():
+        resolved = cls.resolve_upstream_setting(upstream_url)
+        if resolved:
             return cls._start_attached(
                 sources=sources,
-                upstream_url=upstream_url.strip(),
+                upstream_url=resolved,
                 config_dir=config_dir,
                 container_name=attached_container_name,
                 ready_timeout_sec=ready_timeout_sec,

backend/tests/test_hls_preview_api.py

@@ -44,6 +44,13 @@ def test_docker_publish_bind_host_maps_docker_internal() -> None:
     assert docker_publish_bind_host("127.0.0.1") == "127.0.0.1"
 
 
+def test_resolve_upstream_setting() -> None:
+    assert HlsPreviewManager.resolve_upstream_setting("http://127.0.0.1:18888") == (
+        "http://127.0.0.1:18888"
+    )
+    assert HlsPreviewManager.resolve_upstream_setting("ephemeral") == ""
+
+
 def test_hls_preview_ensure_pull(hls_client: TestClient) -> None:
     fake_sess = HlsPreviewSession(
         upstream_base="http://127.0.0.1:18888",