Fix Deprecation Warning and code cleanup

app/main.py

@@ -5,29 +5,26 @@ from app.utils import generate_short_code
 from dotenv import load_dotenv
 import os
 import sqlite3
+from contextlib import asynccontextmanager
 
-load_dotenv()
+@asynccontextmanager
-
+async def lifespan(app: FastAPI):
-app = FastAPI()
+    conn = sqlite3.connect('urls.db')
-
-DB_PATH = "urls.db"
-
-def get_db_connection():
-    conn = sqlite3.connect(DB_PATH)
-    return conn
-
-# URL schema
-class URLRequest(BaseModel):
-    url: str
-
-@app.on_event("startup")
-def startup():
-    conn = get_db_connection()
     conn.execute('''CREATE TABLE IF NOT EXISTS urls
                     (id INTEGER PRIMARY KEY, short_code TEXT, original_url TEXT, clicks INTEGER)''')
     conn.commit()
+    yield
     conn.close()
 
+app = FastAPI(lifespan=lifespan)
+
+def get_db_connection():
+    conn = sqlite3.connect('urls.db')
+    return conn
+
+class URLRequest(BaseModel):
+    url: str
+
 @app.get("/")
 def home():
     return {"message": "URL Shortener API"}
@@ -35,7 +32,6 @@ def home():
 @app.post("/shorten")
 def shorten_url(request: URLRequest):
     short_code = generate_short_code()
-
     conn = get_db_connection()
 
     while conn.execute("SELECT 1 FROM urls WHERE short_code = ?", (short_code,)).fetchone():
@@ -57,7 +53,6 @@ def redirect_to_url(short_code: str):
         raise HTTPException(status_code=404, detail="Shortened URL not found")
 
     original_url, clicks = url_data
-
     conn.execute("UPDATE urls SET clicks = ? WHERE short_code = ?", (clicks + 1, short_code))
     conn.commit()
     conn.close()