---
id: 8a4ae0ed-5bac-459b-bdd8-d3075bfc108d
type: fix
title: "Fix: Replace manual db.close() calls with FastAPI middleware in paper-dynasty-database"
tags: [paper-dynasty-database, fastapi, peewee, python, middleware, database, connection-management]
importance: 0.7
confidence: 0.8
created: "2026-03-03T05:38:10.354619+00:00"
updated: "2026-03-03T05:38:11.920614+00:00"
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---

## Problem
467 manual `db.close()` calls across 30 router files in `app/routers_v2/`. Any uncaught exception would leak a Peewee DB connection. Brittle to maintain.

## Solution
Added `db_session_middleware` to `app/main.py` using FastAPI's `@app.middleware("http")` decorator:

```python
@app.middleware("http")
async def db_session_middleware(request: Request, call_next):
    try:
        db.connect(reuse_if_open=True)
        response = await call_next(request)
        return response
    finally:
        if not db.is_closed():
            db.close()
```

Used `db.connect(reuse_if_open=True)` — safe for both SQLite and `PooledPostgresqlDatabase` (pool returns connection on close).

Removed all `db.close()` lines from routers with a Python regex script:
```python
re.sub(r'^[ \t]*db\.close\(\)\n', '', content, flags=re.MULTILINE)
```

## Files Changed
- `app/main.py` — added import + middleware (11 lines)
- `app/routers_v2/*.py` — removed db.close() from 30 files

## Notes
- `db.close()` at end of `db_engine.py` (line 1067) is initialization cleanup — intentionally kept
- Some router files now have unused `db` imports (only used for db.close()) — harmless, can clean up later
- PR #33 in paper-dynasty-database