folder create idempotency

backend/src/openapi.rs

@@ -502,7 +502,10 @@ mod doc {
         post,
         path = "/api/folders",
         request_body = CreateFolderRequest,
-        responses((status = 200, description = "Folder created", body = FolderResponse)),
+        responses(
+            (status = 201, description = "Folder created", body = FolderResponse),
+            (status = 200, description = "Folder already existed", body = FolderResponse)
+        ),
         tag = "Folders"
     )]
     pub(super) fn create_folder() {}

backend/src/routes/folders.rs

@@ -179,7 +179,7 @@ pub async fn create_folder(
         ..
     }: TenantScopedConn,
     Json(payload): Json<CreateFolderRequest>,
-) -> AppResult<Json<FolderResponse>> {
+) -> AppResult<(StatusCode, Json<FolderResponse>)> {
     if payload.name.trim().is_empty() {
         return Err(AppError::bad_request("name must not be empty"));
     }
@@ -202,8 +202,8 @@ pub async fn create_folder(
             .optional()?
     };
 
-    let folder: Folder = if let Some(folder) = existing {
-        folder
+    let (folder, created): (Folder, bool) = if let Some(folder) = existing {
+        (folder, false)
     } else {
         let new_folder = NewFolder {
             id: Uuid::new_v4(),
@@ -220,28 +220,43 @@ pub async fn create_folder(
             .optional()?;
 
         if let Some(id) = inserted_id {
-            folders::table
-                .find(id)
-                .filter(folders::tenant_id.eq(tenant_id))
-                .first(&mut conn)?
+            (
+                folders::table
+                    .find(id)
+                    .filter(folders::tenant_id.eq(tenant_id))
+                    .first(&mut conn)?,
+                true,
+            )
         } else if let Some(parent_id) = payload.parent_id {
-            folders::table
-                .filter(folders::tenant_id.eq(tenant_id))
-                .filter(folders::parent_id.eq(Some(parent_id)))
-                .filter(folders::name.eq(name))
-                .first(&mut conn)?
+            (
+                folders::table
+                    .filter(folders::tenant_id.eq(tenant_id))
+                    .filter(folders::parent_id.eq(Some(parent_id)))
+                    .filter(folders::name.eq(name))
+                    .first(&mut conn)?,
+                false,
+            )
         } else {
-            folders::table
-                .filter(folders::tenant_id.eq(tenant_id))
-                .filter(folders::parent_id.is_null())
-                .filter(folders::name.eq(name))
-                .first(&mut conn)?
+            (
+                folders::table
+                    .filter(folders::tenant_id.eq(tenant_id))
+                    .filter(folders::parent_id.is_null())
+                    .filter(folders::name.eq(name))
+                    .first(&mut conn)?,
+                false,
+            )
         }
     };
 
-    Ok(Json(FolderResponse {
+    let response = Json(FolderResponse {
         folder: folder_to_info(folder),
-    }))
+    });
+
+    if created {
+        Ok((StatusCode::CREATED, response))
+    } else {
+        Ok((StatusCode::OK, response))
+    }
 }
 
 pub async fn list_folder_contents(