add a new endpoint returning a devious cat

c2.service

@@ -4,9 +4,8 @@ After=network.target
 
 [Service]
 Type=simple
-WorkingDirectory=/home/kemp/ins/teaching/workshop-c-and-c-server
+WorkingDirectory=/root/workshop-c-and-c
-# Run the requested command. This uses /usr/bin/env to locate `uv` in PATH.
+ExecStart=/usr/bin/python3 main.py
-ExecStart=/usr/bin/env uv run main.py
 # Ensure common system paths are available when using /usr/bin/env
 Environment=PATH=/usr/local/bin:/usr/bin:/bin
 Environment=PYTHONUNBUFFERED=1

main.py

@@ -1,10 +1,12 @@
-from fastapi import FastAPI, Request, Response
+import base64
-from fastapi.responses import HTMLResponse
 import threading
 from datetime import datetime
-import base64
+from pathlib import Path
+from typing import Dict, List
+
 import uvicorn
-from typing import List, Dict
+from fastapi import FastAPI, Request, Response
+from fastapi.responses import FileResponse, HTMLResponse
 
 app = FastAPI(title="Tiny C2 (Workshop)")
 
@@ -16,6 +18,7 @@ _lock = threading.Lock()
 # A 1x1 transparent PNG (base64) used as a static beacon image.
 _1x1_png_b64 = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z/C/HgAGgwJ/lK3Q6wAAAABJRU5ErkJggg=="
 _IMAGE_BYTES = base64.b64decode(_1x1_png_b64)
+_CAT_PATH = Path(__file__).resolve().parent / "cat.jpg"
 
 
 def _record_session(value: str, ip: str) -> None:
@@ -50,6 +53,24 @@ async def beacon(session: str, request: Request):
     return Response(content=_IMAGE_BYTES, media_type="image/png", headers=headers)
 
 
+@app.get("/cat/{session}", response_class=Response)
+async def cat_image(session: str, request: Request):
+    """
+    Serves the local cat.jpg file as a static image.
+    """ 
+    client_ip = request.client.host if request.client else "unknown"
+    # session is provided by the URL path; FastAPI will have decoded percent-encoding
+    if session:
+        _record_session(session, client_ip)
+
+    headers = {
+        "Cache-Control": "no-cache, no-store, must-revalidate",
+        "Pragma": "no-cache",
+        "Expires": "0",
+    }
+    return FileResponse(_CAT_PATH, media_type="image/jpeg", headers=headers)
+
+
 @app.get("/sessions", response_class=HTMLResponse)
 async def sessions_list():
     """