diff --git a/src/main.rs b/src/main.rs
index 72ac862..f2a90e5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,5 @@
 use axum::extract::Query;
-use axum::http::{HeaderMap, HeaderValue, Uri};
+use axum::http::{HeaderMap, HeaderValue};
 use axum::response::{Html, Redirect};
 use axum::{extract::State, http::StatusCode, response::IntoResponse, routing::get, Form, Router};
 use minijinja::{context, Environment};
@@ -94,12 +94,9 @@ async fn auth(
             return StatusCode::UNAUTHORIZED;
         };
         let mut locked = state.session.lock().await;
-        if locked.contains_key(&s) {
+        if let std::collections::hash_map::Entry::Occupied(mut e) = locked.entry(s) {
             // FIX, when accessed /auth with correct cookie, the cookie's expiration is delayed
-            let Some(v) = locked.insert(
-                s,
-                Instant::now() + Duration::from_secs(*SESSION_ACTIVE_TIME),
-            ) else {
+            let Some(v) = Some(e.insert(Instant::now() + Duration::from_secs(*SESSION_ACTIVE_TIME))) else {
                 tracing::info!("session:{} extended", session_token.value());
                 return StatusCode::UNAUTHORIZED;
             };
@@ -108,13 +105,13 @@ async fn auth(
             }
         }
     }
-    return StatusCode::UNAUTHORIZED;
+    StatusCode::UNAUTHORIZED
 }
 
 async fn login(
     State(state): State<Arc<ServerState>>,
     cookies: Cookies,
-    Query(mut params): Query<HashMap<String, String>>,
+    Query(params): Query<HashMap<String, String>>,
     Form(frm): Form<UserLoginForm>,
 ) -> Result<Redirect, (StatusCode, &'static str)> {
     let conn = state.db.acquire().await;
@@ -137,14 +134,14 @@ async fn login(
             let s = Uuid::new_v4();
             let mut locked = state.session.lock().await;
             locked.insert(
-                s.clone(),
+                s,
                 Instant::now() + Duration::from_secs(*SESSION_ACTIVE_TIME),
             );
             let mut new_cookie = Cookie::new(&*COOKIE_NAME, s.to_string());
             new_cookie.set_domain(".aaronhu.cn");
             cookies.add(new_cookie);
             if let Some(original_uri) = params.get("original_url") {
-                return Ok(Redirect::to(&original_uri));
+                return Ok(Redirect::to(original_uri));
             }
 
             return Err((StatusCode::ACCEPTED, "ok"));
@@ -152,7 +149,7 @@ async fn login(
             return Err((StatusCode::UNAUTHORIZED, "wrong password"));
         }
     }
-    return Err((StatusCode::BAD_GATEWAY, "unreachable"));
+    Err((StatusCode::BAD_GATEWAY, "unreachable"))
 }
 
 async fn login_page(headers: HeaderMap<HeaderValue>) -> impl IntoResponse {
@@ -173,11 +170,11 @@ async fn login_page(headers: HeaderMap<HeaderValue>) -> impl IntoResponse {
             }
         }
     }
-    return Html(
+    Html(
         template
             .render(context! { url => String::new() })
             .unwrap_or("Error".to_string()),
-    );
+    )
 }
 
 pub fn check_otp(key_from_db: String, user_input_otp: String) -> bool {
@@ -196,7 +193,7 @@ pub fn check_otp(key_from_db: String, user_input_otp: String) -> bool {
             return token == user_input_otp;
         }
     }
-    return false;
+    false
 }
 
 async fn gc(state: Arc<ServerState>) -> Result<(), String> {