build api and frountend

python/ebook_search/api/bm25_tasks.py

@@ -0,0 +1,58 @@
+"""Background BM25 refresh tasks for the web app."""
+
+from __future__ import annotations
+
+import logging
+from threading import Timer
+from typing import TYPE_CHECKING
+
+from sqlalchemy.orm import Session
+
+from python.ebook_search.bm25_corpus import refresh_bm25_corpus
+
+if TYPE_CHECKING:
+    from fastapi import FastAPI
+    from sqlalchemy.engine import Engine
+
+    from python.ebook_search.config import EbookSearchConfig
+
+logger = logging.getLogger(__name__)
+
+
+def schedule_bm25_refresh(app: FastAPI) -> None:
+    """Schedule a delayed BM25 corpus refresh, replacing any pending refresh."""
+    existing_timer = getattr(app.state, "bm25_refresh_timer", None)
+    if existing_timer is not None:
+        existing_timer.cancel()
+
+    timer = Timer(app.state.config.bm25_refresh_delay_seconds, refresh_bm25_for_app, args=(app,))
+    timer.daemon = True
+    timer.start()
+    app.state.bm25_refresh_timer = timer
+    logger.info(
+        "ebook_bm25_refresh_scheduled delay_seconds=%s",
+        app.state.config.bm25_refresh_delay_seconds,
+    )
+
+
+def cancel_bm25_refresh(app: FastAPI) -> None:
+    """Cancel any pending BM25 corpus refresh."""
+    existing_timer = getattr(app.state, "bm25_refresh_timer", None)
+    if existing_timer is not None:
+        existing_timer.cancel()
+        app.state.bm25_refresh_timer = None
+        logger.info("ebook_bm25_refresh_cancelled")
+
+
+def refresh_bm25_for_app(app: FastAPI) -> None:
+    """Refresh the BM25 corpus using the app engine and config."""
+    try:
+        refresh_bm25_for_engine(app.state.engine, app.state.config)
+    except Exception:
+        logger.exception("ebook_bm25_refresh_failed")
+
+
+def refresh_bm25_for_engine(engine: Engine, config: EbookSearchConfig) -> None:
+    """Refresh the BM25 corpus using a SQLAlchemy engine."""
+    with Session(engine) as session:
+        refresh_bm25_corpus(session, config)