baseline: Clover 独立仓库首次基线提交

将 Clover 从上层产品包旧仓库中独立出来,建立专属版本控制。
当前状态=纵切片端到端已打通(登录→选品→出文出图→审核→下载包),
M1文案质量去套路化已验收。此提交作为后续按核销清单逐条修复的基线。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/app/utils/sse_utils.py

@@ -0,0 +1,122 @@
+"""
+app/utils/sse_utils.py — SSE 工具函数（按 Lead 规范路径）
+补发历史事件、event_seq 去重、Redis pub/sub 推送。
+供 api/v1/stream.py 和 AIE worker 共用。
+"""
+
+import asyncio
+import json
+import logging
+from typing import Any, AsyncGenerator
+
+from app.core.config import get_settings
+
+logger = logging.getLogger(__name__)
+settings = get_settings()
+
+# SSE 事件类型（契约§2全列）
+SSE_EVENT_TYPES = frozenset({
+    "task_started", "analyze_done", "text_progress", "text_candidate",
+    "image_progress", "image_candidate", "flywheel_injected",
+    "batch_failed", "task_done", "error", "heartbeat",
+})
+
+_HISTORY_KEY_TPL = "sse:task:{task_id}:events"
+_CHANNEL_TPL = "sse:task:{task_id}"
+_HISTORY_TTL_SECONDS = 3600  # 历史事件保留 1h
+
+
+def format_sse(event: str, data: dict, seq: int | None = None) -> str:
+    """格式化单条 SSE 消息（text/event-stream 格式）。"""
+    payload = json.dumps(data, ensure_ascii=False)
+    lines = [f"event: {event}", f"data: {payload}"]
+    if seq is not None:
+        lines.append(f"id: {seq}")
+    return "\n".join(lines) + "\n\n"
+
+
+async def push_event(
+    redis_client,
+    task_id: int,
+    workspace_id: int,
+    event: str,
+    data: dict[str, Any],
+    seq: int,
+) -> None:
+    """
+    推送事件到 Redis：
+    1. 追加到历史 list（供断线重连补发）
+    2. Publish 到 channel（供在线客户端实时收）
+    """
+    if event not in SSE_EVENT_TYPES:
+        logger.warning("Unknown SSE event type: %s", event)
+
+    record = {"event": event, "data": data, "seq": seq, "workspace_id": workspace_id}
+    payload = json.dumps(record, ensure_ascii=False)
+
+    hist_key = _HISTORY_KEY_TPL.format(task_id=task_id)
+    channel = _CHANNEL_TPL.format(task_id=task_id)
+
+    await redis_client.rpush(hist_key, payload)
+    await redis_client.expire(hist_key, _HISTORY_TTL_SECONDS)
+    await redis_client.publish(channel, payload)
+
+
+async def get_history_events(
+    redis_client, task_id: int, after_seq: int
+) -> list[dict]:
+    """取 task 历史事件中 seq > after_seq 的部分（断线重连补发）。"""
+    hist_key = _HISTORY_KEY_TPL.format(task_id=task_id)
+    try:
+        raw_list = await redis_client.lrange(hist_key, 0, -1)
+        result = []
+        for raw in raw_list:
+            ev = json.loads(raw)
+            if ev.get("seq", 0) > after_seq:
+                result.append(ev)
+        return result
+    except Exception as exc:
+        logger.warning("get_history_events failed task=%s: %s", task_id, exc)
+        return []
+
+
+async def stream_events(
+    redis_client,
+    task_id: int,
+    workspace_id: int,
+    last_seq: int = 0,
+    heartbeat_interval: int = 25,
+) -> AsyncGenerator[str, None]:
+    """
+    主 SSE 生成器：
+    1. 先补发 last_seq 之后的历史事件
+    2. 再订阅 Redis channel 实时推新事件
+    3. 每 heartbeat_interval 秒推一次保活 heartbeat
+    """
+    # 1. 补发历史
+    history = await get_history_events(redis_client, task_id, last_seq)
+    for ev in history:
+        yield format_sse(ev["event"], ev["data"], ev.get("seq"))
+
+    # 2. 实时订阅
+    pubsub = redis_client.pubsub()
+    channel = _CHANNEL_TPL.format(task_id=task_id)
+    await pubsub.subscribe(channel)
+    elapsed = 0
+    try:
+        while True:
+            msg = await pubsub.get_message(ignore_subscribe_messages=True, timeout=1.0)
+            if msg and msg["type"] == "message":
+                ev = json.loads(msg["data"])
+                if ev.get("workspace_id") != workspace_id:
+                    continue  # 防越权订阅他人任务
+                yield format_sse(ev["event"], ev["data"], ev.get("seq"))
+                if ev["event"] in ("task_done", "error"):
+                    break
+            else:
+                elapsed += 1
+                if elapsed >= heartbeat_interval:
+                    elapsed = 0
+                    yield format_sse("heartbeat", {"ts": asyncio.get_event_loop().time()})
+    finally:
+        await pubsub.unsubscribe(channel)