feat(alarm): add alarm snapshot viewing functionality

main.py

@@ -11,11 +11,14 @@ os.environ["TENSORRT_DISABLE_MYELIN"] = "1"
 
 import cv2
 import numpy as np
-from fastapi import FastAPI, HTTPException
+from fastapi import FastAPI, HTTPException, Depends
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import FileResponse, StreamingResponse
+from sqlalchemy.orm import Session
 from prometheus_client import start_http_server
 
+from db.models import get_db
+
 sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
 
 from ultralytics.engine.results import Boxes as UltralyticsBoxes
@@ -144,6 +147,23 @@ async def get_snapshot_base64(camera_id: int):
     return {"image": base64.b64encode(buffer).decode("utf-8")}
 
 
+@app.get("/api/alarms/{alarm_id}/snapshot")
+async def get_alarm_snapshot(alarm_id: int, db: Session = Depends(get_db)):
+    from db.models import Alarm
+
+    alarm = db.query(Alarm).filter(Alarm.id == alarm_id).first()
+    if not alarm:
+        raise HTTPException(status_code=404, detail="告警不存在")
+
+    if not alarm.snapshot_path:
+        raise HTTPException(status_code=404, detail="该告警没有截图")
+
+    if not os.path.exists(alarm.snapshot_path):
+        raise HTTPException(status_code=404, detail="截图文件不存在")
+
+    return FileResponse(alarm.snapshot_path, media_type="image/jpeg")
+
+
 @app.get("/api/camera/{camera_id}/detect")
 async def get_detection_with_overlay(camera_id: int):
     pipeline = get_pipeline()