fix(backend): replace blocking std::fs with async tokio::fs

backend/src/handlers/mod.rs

@@ -189,16 +189,21 @@ async fn delete_torrent_with_data(
     })?;
 
     // Resolve Paths (Canonicalize) to prevent .. traversal and symlink attacks
-    let root_path = std::fs::canonicalize(std::path::Path::new(&root_path_str)).map_err(|e| {
-        (
-            StatusCode::INTERNAL_SERVER_ERROR,
-            format!("Invalid download root configuration (on server): {}", e),
-        )
-    })?;
+    let root_path = tokio::fs::canonicalize(std::path::Path::new(&root_path_str))
+        .await
+        .map_err(|e| {
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                format!("Invalid download root configuration (on server): {}", e),
+            )
+        })?;
 
     // Check if target path exists before trying to resolve it
     let target_path_raw = std::path::Path::new(&path);
-    if !target_path_raw.exists() {
+    if !tokio::fs::try_exists(target_path_raw)
+        .await
+        .unwrap_or(false)
+    {
         tracing::warn!(
             "Data path not found: {:?}. Removing torrent only.",
             target_path_raw
@@ -214,12 +219,14 @@ async fn delete_torrent_with_data(
         return Ok("Torrent removed (Data not found)");
     }
 
-    let target_path = std::fs::canonicalize(target_path_raw).map_err(|e| {
-        (
-            StatusCode::INTERNAL_SERVER_ERROR,
-            format!("Invalid data path: {}", e),
-        )
-    })?;
+    let target_path = tokio::fs::canonicalize(target_path_raw)
+        .await
+        .map_err(|e| {
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                format!("Invalid data path: {}", e),
+            )
+        })?;
 
     tracing::info!(
         "Delete request: Target='{:?}', Root='{:?}'",
@@ -258,9 +265,9 @@ async fn delete_torrent_with_data(
 
     // 3. Delete Files via Native FS
     let delete_result = if target_path.is_dir() {
-        std::fs::remove_dir_all(&target_path)
+        tokio::fs::remove_dir_all(&target_path).await
     } else {
-        std::fs::remove_file(&target_path)
+        tokio::fs::remove_file(&target_path).await
     };
 
     match delete_result {
@@ -601,14 +608,18 @@ pub async fn set_global_limit_handler(
     if let Some(down) = payload.max_download_rate {
         // Convert bytes/s to KB/s (divide by 1024)
         let down_kb = down / 1024;
-        tracing::info!("Setting download limit: {} bytes/s = {} KB/s", down, down_kb);
-        
+        tracing::info!(
+            "Setting download limit: {} bytes/s = {} KB/s",
+            down,
+            down_kb
+        );
+
         // Use set_kb with empty string as first param (throttle name), then value
         if let Err(e) = client
-            .call("throttle.global_down.max_rate.set_kb", &[
-                RpcParam::from(""),
-                RpcParam::Int(down_kb),
-            ])
+            .call(
+                "throttle.global_down.max_rate.set_kb",
+                &[RpcParam::from(""), RpcParam::Int(down_kb)],
+            )
             .await
         {
             tracing::error!("Failed to set download limit: {}", e);
@@ -624,12 +635,12 @@ pub async fn set_global_limit_handler(
         // Convert bytes/s to KB/s
         let up_kb = up / 1024;
         tracing::info!("Setting upload limit: {} bytes/s = {} KB/s", up, up_kb);
-        
+
         if let Err(e) = client
-            .call("throttle.global_up.max_rate.set_kb", &[
-                RpcParam::from(""),
-                RpcParam::Int(up_kb),
-            ])
+            .call(
+                "throttle.global_up.max_rate.set_kb",
+                &[RpcParam::from(""), RpcParam::Int(up_kb)],
+            )
             .await
         {
             tracing::error!("Failed to set upload limit: {}", e);