Use count API endpoint for comments

Based on arsnova-comment-service commit
  b88aa32c54ba773373b817d36313787ae895e809

src/app/components/shared/room-page/room-page.component.ts

@@ -35,9 +35,9 @@ export class RoomPageComponent implements OnInit {
     this.roomService.getRoomByShortId(id).subscribe(room => {
       this.room = room;
       this.isLoading = false;
-      this.commentService.getComments(this.room.id)
-        .subscribe(comments => {
-          this.commentCounter = comments.length;
+      this.commentService.countByRoomId(this.room.id)
+        .subscribe(commentCounter => {
+          this.commentCounter = commentCounter;
         });
       this.wsCommentService.getCommentStream(this.room.id).subscribe((message: Message) => {
         const msg = JSON.parse(message.body);

src/app/services/http/comment.service.ts

@@ -14,7 +14,8 @@ export class CommentService extends BaseHttpService {
   private apiUrl = {
     base: '/api',
     comment: '/comment',
-    find: '/find'
+    find: '/find',
+    count: '/count'
   };
 
   constructor(private http: HttpClient) {
@@ -74,4 +75,15 @@ export class CommentService extends BaseHttpService {
       catchError(this.handleError<Comment>('deleteComment'))
     );
   }
+
+  countByRoomId(roomId: string): Observable<number> {
+    const connectionUrl = this.apiUrl.base + this.apiUrl.comment + this.apiUrl.find + this.apiUrl.count;
+    return this.http.post<number>(connectionUrl, {
+      properties: { roomId: roomId },
+      externalFilters: {}
+    }, httpOptions).pipe(
+      tap(_ => ''),
+      catchError(this.handleError<number>('countByRoomId', 0))
+    );
+  }
 }