feat: cancel playlist adding mid-operation (closes #840)

app/main.py

@@ -302,6 +302,11 @@ async def add(request):
     )
     return web.Response(text=serializer.encode(status))
 
+@routes.post(config.URL_PREFIX + 'cancel-add')
+async def cancel_add(request):
+    dqueue.cancel_add()
+    return web.Response(text=serializer.encode({'status': 'ok'}), content_type='application/json')
+
 @routes.post(config.URL_PREFIX + 'delete')
 async def delete(request):
     post = await request.json()
@@ -433,6 +438,7 @@ async def add_cors(request):
     return web.Response(text=serializer.encode({"status": "ok"}))
 
 app.router.add_route('OPTIONS', config.URL_PREFIX + 'add', add_cors)
+app.router.add_route('OPTIONS', config.URL_PREFIX + 'cancel-add', add_cors)
 
 async def on_prepare(request, response):
     if 'Origin' in request.headers:

app/ytdl.py

@@ -535,6 +535,11 @@ class DownloadQueue:
         self.active_downloads = set()
         self.semaphore = asyncio.Semaphore(int(self.config.MAX_CONCURRENT_DOWNLOADS))
         self.done.load()
+        self._add_canceled = False
+
+    def cancel_add(self):
+        self._add_canceled = True
+        log.info('Playlist add operation canceled by user')
 
     async def __import_queue(self):
         for k, v in self.queue.saved_items():
@@ -699,6 +704,9 @@ class DownloadQueue:
                 log.info(f'Item limit is set. Processing only first {playlist_item_limit} entries')
                 entries = entries[:playlist_item_limit]
             for index, etr in enumerate(entries, start=1):
+                if self._add_canceled:
+                    log.info(f'Playlist add canceled after processing {len(already)} entries')
+                    return {'status': 'ok', 'msg': f'Canceled - added {len(already)} items before cancel'}
                 etr["_type"] = "video"
                 etr[etype] = entry.get("id") or entry.get("channel_id") or entry.get("channel")
                 etr[f"{etype}_index"] = '{{0:0{0:d}d}}'.format(index_digits).format(index)
@@ -771,6 +779,8 @@ class DownloadQueue:
             f'{playlist_item_limit=} {auto_start=} {split_by_chapters=} {chapter_template=} '
             f'{subtitle_format=} {subtitle_language=} {subtitle_mode=}'
         )
+        if already is None:
+            self._add_canceled = False
         already = set() if already is None else already
         if url in already:
             log.info('recursion detected, skipping')

ui/src/app/app.html

@@ -98,15 +98,17 @@
               name="addUrl"
               [(ngModel)]="addUrl"
               [disabled]="addInProgress || downloads.loading">
-            <button class="btn btn-primary btn-lg px-4"
-              type="submit"
-              (click)="addDownload()"
-              [disabled]="addInProgress || downloads.loading">
-              @if (addInProgress) {
-                <span class="spinner-border spinner-border-sm" role="status" id="add-spinner"></span>
-              }
-              {{ addInProgress ? "Adding..." : "Download" }}
-            </button>
+            @if (addInProgress) {
+              <button class="btn btn-danger btn-lg px-3" type="button" (click)="cancelAdding()">
+                <fa-icon [icon]="faTimesCircle" class="me-1" /> Cancel
+              </button>
+            } @else {
+              <button class="btn btn-primary btn-lg px-4" type="submit"
+                (click)="addDownload()"
+                [disabled]="downloads.loading">
+                Download
+              </button>
+            }
           </div>
         </div>
       </div>

ui/src/app/app.ts

@@ -433,6 +433,13 @@ export class App implements AfterViewInit, OnInit {
     });
   }
 
+  cancelAdding() {
+    this.downloads.cancelAdd().subscribe({
+      next: () => { this.addInProgress = false; },
+      error: () => { this.addInProgress = false; }
+    });
+  }
+
   downloadItemByKey(id: string) {
     this.downloads.startById([id]).subscribe();
   }

ui/src/app/services/downloads.service.ts

@@ -208,6 +208,9 @@ export class DownloadsService {
   public exportQueueUrls(): string[] {
     return Array.from(this.queue.values()).map(download => download.url);
   }
-  
-  
+  public cancelAdd() {
+    return this.http.post<any>('cancel-add', {}).pipe(
+      catchError(this.handleHTTPError)
+    );
+  }
 }