diff --git a/packages/hydrooj/src/handler/contest.ts b/packages/hydrooj/src/handler/contest.ts
index 9ffe4efa9..5b681cb53 100644
--- a/packages/hydrooj/src/handler/contest.ts
+++ b/packages/hydrooj/src/handler/contest.ts
@@ -81,6 +81,7 @@ export class ContestListHandler extends Handler {
             ...rule ? { rule } : { rule: { $in: rules } },
             ...group ? { assign: { $in: [group] } } : {},
         };
+        await this.ctx.parallel('contest/list', q, this);
         const cursor = contest.getMulti(domainId, q).sort({ endAt: -1, beginAt: -1, _id: -1 });
         let qs = rule ? `rule=${rule}` : '';
         if (group) qs += qs ? `&group=${group}` : `group=${group}`;
diff --git a/packages/hydrooj/src/service/bus.ts b/packages/hydrooj/src/service/bus.ts
index 888724415..fecf86a30 100644
--- a/packages/hydrooj/src/service/bus.ts
+++ b/packages/hydrooj/src/service/bus.ts
@@ -94,6 +94,7 @@ export interface EventMap extends LifecycleEvents, HandlerEvents {
 
     'contest/before-add': (payload: Partial<Tdoc>) => VoidReturn
     'contest/add': (payload: Partial<Tdoc>, id: ObjectId) => VoidReturn
+    'contest/list': (query: Fileter<Tdoc>, handler: any) => VoidReturn
     'contest/scoreboard': (tdoc: Tdoc, rows: ScoreboardRow[], udict: BaseUserDict, pdict: ProblemDict) => VoidReturn
     'contest/balloon': (domainId: string, tid: ObjectId, bdoc: ContestBalloonDoc) => VoidReturn