feat：新增演示

.env.example

@@ -41,6 +41,8 @@ SCREEN_MAX_MB=10
 # 回收站里的大屏保留多少天，超过后自动彻底删除
 TRASH_RETENTION_DAYS=30
 THUMBNAIL_DIR=data/thumbnails
+# 未登录演示：展示这个用户 ID 名下的大屏（用该账号登录后在编辑器里做即可）；留空则没有演示数据
+DEMO_OWNER_ID=
 
 # 模型写的单条数据查询的超时（秒）
 DATA_QUERY_TIMEOUT=10

app/api/public.py

@@ -2,17 +2,59 @@
 
 from typing import Annotated, Any
 
-from fastapi import APIRouter, Query
+from fastapi import APIRouter, Query, Response
 from fastapi.responses import FileResponse
 
-from app.api.screens import Service
+from app.api.screens import Service, thumbnail_url
 from app.common.response import ApiResponse, success_response
+from app.config import settings
 from app.core.exceptions import BizException
-from app.schemas.saved_screen import PublicScreen
+from app.schemas.saved_screen import (
+    DemoScreen,
+    DemoScreenList,
+    PublicScreen,
+    PublishBrief,
+)
 from app.services.screens import LIVE_VARS_MAX_CHARS, public_page
 
 router = APIRouter(prefix="/public", tags=["Public"])
 
+# 演示数据的条数上限和浏览器缓存时长（秒）
+DEMO_LIMIT = 20
+DEMO_CACHE_SECONDS = 60
+
+
+@router.get("/demo/screens")
+async def list_demo_screens(
+    service: Service, response: Response
+) -> ApiResponse[DemoScreenList]:
+    """未登录演示：演示账号（DEMO_OWNER_ID）下的大屏，页面去掉数据源 headers；没配账号时为空"""
+    owner_id = settings.demo_owner_id
+    if owner_id is None:
+        return success_response(DemoScreenList(items=[]))
+    records = await service.list_demo(owner_id, DEMO_LIMIT)
+    response.headers["Cache-Control"] = f"public, max-age={DEMO_CACHE_SECONDS}"
+    return success_response(
+        DemoScreenList(
+            items=[
+                DemoScreen(
+                    screen_id=record.screen_id,
+                    name=record.name,
+                    page=public_page(record.page),
+                    thumbnail_url=thumbnail_url(record.thumbnail),
+                    revision=record.revision,
+                    updated_at=record.updated_at,
+                    publish=None
+                    if record.publish is None
+                    else PublishBrief.model_validate(
+                        record.publish.model_dump(exclude={"revision"})
+                    ),
+                )
+                for record in records
+            ]
+        )
+    )
+
 
 @router.get("/screens/{share_id}")
 async def get_public_screen(

app/config.py

@@ -133,6 +133,13 @@ class Settings:
         )
     )
 
+    # 演示账号的用户 ID：未登录访问时展示这个账号下的大屏，不配置则没有演示数据
+    demo_owner_id: int | None = field(
+        default_factory=lambda: (
+            int(value) if (value := os.getenv("DEMO_OWNER_ID", "").strip()) else None
+        )
+    )
+
     # 模型写的单条数据查询的超时（秒）
     data_query_timeout: float = field(
         default_factory=lambda: float(os.getenv("DATA_QUERY_TIMEOUT", "10"))

app/schemas/saved_screen.py

@@ -109,6 +109,22 @@ class ScreenDetail(BaseModel):
     publish: PublishBrief | None
 
 
+class DemoScreen(BaseModel):
+    """未登录演示用的大屏：带页面，前端据此在内存里还原一份可随意修改的大屏列表"""
+
+    screen_id: str
+    name: str
+    page: dict[str, Any]
+    thumbnail_url: str | None
+    revision: int
+    updated_at: datetime
+    publish: PublishBrief | None
+
+
+class DemoScreenList(BaseModel):
+    items: list[DemoScreen]
+
+
 class ScreenSaved(BaseModel):
     revision: int
     updated_at: datetime

app/services/screens.py

@@ -428,6 +428,21 @@ class ScreenService:
             deleted=deleted,
         )
 
+    async def list_demo(self, owner_id: int, limit: int) -> list[ScreenRecord]:
+        """演示账号下没删除的大屏（最近修改在前），带页面"""
+        summaries, _ = await self._store.search(
+            owner_id,
+            keyword=None,
+            status=None,
+            sort="updated_at",
+            descending=True,
+            limit=limit,
+            offset=0,
+            deleted=False,
+        )
+        records = [await self._store.get(item.screen_id, owner_id) for item in summaries]
+        return [record for record in records if record is not None]
+
     async def copy_screen(self, screen_id: str, owner_id: int, name: str | None) -> str:
         """只复制草稿和封面，不复制发布状态和历史"""
         source = await self.get(screen_id, owner_id)