From c0d135d8a8b23c9b7b71a5c89d79ad52484cf318 Mon Sep 17 00:00:00 2001
From: Xevion <xevion@xevion.dev>
Date: Thu, 24 Oct 2024 04:04:09 -0500
Subject: [PATCH] revamp ip address demo, buffered background IP submit with
 upsert, parameterized SQL with psycopg2 cursor & execute_values

---
 backend/linkpulse/app.py | 124 ++++++++++++++++++++++++++++++---------
 1 file changed, 96 insertions(+), 28 deletions(-)

diff --git a/backend/linkpulse/app.py b/backend/linkpulse/app.py
index 042c0ad..69b9bf2 100644
--- a/backend/linkpulse/app.py
+++ b/backend/linkpulse/app.py
@@ -1,26 +1,94 @@
+import logging
+import random
+from collections import defaultdict
 from contextlib import asynccontextmanager
+from dataclasses import dataclass, field
 from datetime import datetime
 from typing import AsyncIterator
-from fastapi import FastAPI, Request
-from fastapi.middleware.cors import CORSMiddleware
+
 from dotenv import load_dotenv
+from fastapi import FastAPI, Request, Response, status
+from fastapi.middleware.cors import CORSMiddleware
 from fastapi_cache import FastAPICache
 from fastapi_cache.backends.inmemory import InMemoryBackend
 from fastapi_cache.decorator import cache
+from fastapi_utils.tasks import repeat_every
+import human_readable
+from linkpulse.utilities import get_ip, hide_ip, pluralize
 from peewee import PostgresqlDatabase
+from psycopg2.extras import execute_values
+from apscheduler.schedulers.background import BackgroundScheduler
+from apscheduler.triggers.interval import IntervalTrigger
 
 load_dotenv(dotenv_path=".env")
 
-from linkpulse import models  # type: ignore
+from linkpulse import models, responses  # type: ignore
 
 db: PostgresqlDatabase = models.BaseModel._meta.database
 
 
+def flush_ips():
+    if len(app.state.buffered_updates) == 0:
+        return
+
+    try:
+        with db.atomic():
+            sql = """
+                WITH updates (ip, last_seen, increment) AS (VALUES %s)
+                INSERT INTO ipaddress (ip, last_seen, count)
+                SELECT ip, last_seen, increment
+                FROM updates
+                ON CONFLICT (ip)
+                DO UPDATE
+                SET count = ipaddress.count + EXCLUDED.count, last_seen = EXCLUDED.last_seen;
+            """
+            rows = [
+                (ip, data.last_seen, data.count)
+                for ip, data in app.state.buffered_updates.items()
+            ]
+
+            cur = db.cursor()
+            execute_values(cur, sql, rows)
+    except:
+        print("Failed to flush IPs to the database.")
+
+    i = len(app.state.buffered_updates)
+    print("Flushed {} IP{} to the database.".format(i, pluralize(i)))
+
+    # Finish up
+    app.state.buffered_updates.clear()
+
+
+scheduler = BackgroundScheduler()
+scheduler.add_job(flush_ips, IntervalTrigger(seconds=5))
+
+
 @asynccontextmanager
 async def lifespan(_: FastAPI) -> AsyncIterator[None]:
-    FastAPICache.init(backend=InMemoryBackend(), prefix="fastapi-cache", cache_status_header="X-Cache")
+    FastAPICache.init(
+        backend=InMemoryBackend(), prefix="fastapi-cache", cache_status_header="X-Cache"
+    )
+
+    random.seed(42)
+    app.state.ip_pool = [
+        ".".join(str(random.randint(0, 255)) for _ in range(4)) for _ in range(50)
+    ]
+    app.state.buffered_updates = defaultdict(IPCounter)
+
+    scheduler.start()
+
     yield
 
+    scheduler.shutdown()
+    flush_ips()
+
+
+@dataclass
+class IPCounter:
+    # Note: This is not the true 'seen' count, but the count of how many times the IP has been seen since the last flush.
+    count: int = 0
+    last_seen: datetime = field(default_factory=datetime.now)
+
 
 app = FastAPI(lifespan=lifespan)
 
@@ -65,32 +133,32 @@ async def get_migration():
     return {"name": name, "migrated_at": migrated_at}
 
 
-@app.get("/api/test")
-async def get_current_time(request: Request):
-    current_time = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
+logger = logging.getLogger(__name__)
+logger.setLevel(logging.DEBUG)
 
-    user_ip = request.headers.get("X-Forwarded-For")
-    if not user_ip:
-        # Fallback, probably not on a proxy
-        user_ip = request.client.host
 
-    response = {"time": current_time, "ip": user_ip}
+@app.get("/api/ips")
+async def get_ips(request: Request, response: Response):
+    """
+    Returns a list of partially redacted IP addresses, as well as submitting the user's IP address to the database (buffered).
+    """
+    now = datetime.now()
+    # user_ip = get_ip(request)
+    user_ip = random.choice(app.state.ip_pool)
+    if user_ip is None:
+        print("No IP found!")
+        response.status_code = status.HTTP_403_FORBIDDEN
+        return {"error": "Unable to handle request."}
 
-    # Create one record
-    new_ip, created = models.IPAddress.get_or_create(
-        ip=user_ip, defaults={"lastSeen": datetime.now()}
+    # Update the buffered updates
+    app.state.buffered_updates[user_ip].count += 1
+    app.state.buffered_updates[user_ip].last_seen = now
+
+    # Return the IP addresses
+    latest_ips = (
+        models.IPAddress.select(models.IPAddress.ip, models.IPAddress.last_seen, models.IPAddress.count)
+        .order_by(models.IPAddress.last_seen.desc())
+        .limit(10)
     )
-    if not created:
-        new_ip.lastSeen = datetime.now()
-    result = new_ip.save()
-    print(result, new_ip)
 
-    # Query all records
-    for ip in models.IPAddress.select():
-        print(ip.ip, ip.lastSeen)
-
-    message = request.query_params.get("message")
-    if message:
-        response["message"] = message
-
-    return response
+    return {"ips": [responses.SeenIP(ip=hide_ip(ip.ip), last_seen=human_readable.date_time(ip.last_seen), count=ip.count) for ip in latest_ips]}