diff --git a/packages/hydrooj/src/handler/import.ts b/packages/hydrooj/src/handler/import.ts
index bf988bd96..844ed0eb4 100644
--- a/packages/hydrooj/src/handler/import.ts
+++ b/packages/hydrooj/src/handler/import.ts
@@ -1,6 +1,8 @@
+import { sleep } from '@hydrooj/utils';
 import { Context } from '../context';
 import { ValidationError } from '../error';
 import { PERM, PRIV } from '../model/builtin';
+import MessageModel from '../model/message';
 import problem from '../model/problem';
 import { Handler, param, Types } from '../service/server';
 
@@ -15,8 +17,16 @@ class ProblemImportHydroHandler extends Handler {
         if (keepUser) this.checkPriv(PRIV.PRIV_EDIT_SYSTEM);
         if (!this.request.files.file) throw new ValidationError('file');
         if (preferredPrefix && !/^[a-zA-Z]+$/.test(preferredPrefix)) throw new ValidationError('preferredPrefix');
-        await problem.import(domainId, this.request.files.file.filepath, keepUser ? null : this.user._id, preferredPrefix);
-        this.response.redirect = this.url('problem_main');
+        const promise = problem.import(
+            domainId, this.request.files.file.filepath, keepUser ? null : this.user._id,
+            preferredPrefix, this.progress.bind(this),
+        ).catch((e) => MessageModel.send(1, this.user._id, `Import failed: ${e.message}\n${e.stack}`));
+        let resolved = false;
+        await Promise.race([
+            promise.then(() => { resolved = true; }),
+            sleep(5000),
+        ]);
+        this.response.redirect = this.url('problem_main', resolved ? {} : { query: { showImport: 1 } });
     }
 }
 
diff --git a/packages/hydrooj/src/model/problem.ts b/packages/hydrooj/src/model/problem.ts
index ef1bde802..55e0d1357 100644
--- a/packages/hydrooj/src/model/problem.ts
+++ b/packages/hydrooj/src/model/problem.ts
@@ -445,7 +445,7 @@ export class ProblemModel {
         return true;
     }
 
-    static async import(domainId: string, filepath: string, operator = 1, preferredPrefix?: string) {
+    static async import(domainId: string, filepath: string, operator = 1, preferredPrefix?: string, progress = null) {
         let tmpdir = '';
         let del = false;
         try {
@@ -527,7 +527,11 @@ export class ProblemModel {
                     if (count > 5) continue;
                     await RecordModel.add(domainId, docId, operator, f.name.split('.')[1], await fs.readFile(loc, 'utf-8'), true);
                 }
-                if (process.env.HYDRO_CLI) logger.info(`Imported problem ${pdoc.pid} (${pdoc.title})`);
+                if (process.env.HYDRO_CLI) {
+                    logger.info(`Imported problem ${pdoc.pid} (${pdoc.title})`);
+                } else {
+                    progress?.(`Imported problem ${pdoc.pid} (${pdoc.title})`);
+                }
             }
         } finally {
             if (del) await fs.remove(tmpdir);
diff --git a/packages/hydrooj/src/service/server.ts b/packages/hydrooj/src/service/server.ts
index e86a69b1a..54fb52490 100644
--- a/packages/hydrooj/src/service/server.ts
+++ b/packages/hydrooj/src/service/server.ts
@@ -249,7 +249,7 @@ export async function apply(ctx: Context) {
             checkPriv(...args: number[]) {
                 if (!this.user.hasPriv(...args)) throw new PrivilegeError(...args);
             },
-            progress(message: string, params: any[]) {
+            progress(message: string, params: any[] = []) {
                 Hydro.model.message.sendInfo(this.user._id, JSON.stringify({ message, params }));
             },
             async limitRate(
diff --git a/packages/ui-default/components/message/worker.ts b/packages/ui-default/components/message/worker.ts
index 28d722b75..463438260 100644
--- a/packages/ui-default/components/message/worker.ts
+++ b/packages/ui-default/components/message/worker.ts
@@ -9,7 +9,7 @@ console.log('SharedWorker init');
 
 let conn: ReconnectingWebsocket;
 let lcookie: string;
-let ports: MessagePort[] = [];
+const ports: Set<MessagePort> = new Set();
 interface RequestInitSharedConnPayload {
   type: 'conn';
   cookie: string;
@@ -29,6 +29,7 @@ function broadcastMsg(message: any) {
   for (const p of ports) p.postMessage(message);
 }
 function initConn(path: string, port: MessagePort, cookie: any) {
+  ports.add(port);
   if (cookie !== lcookie) conn?.close();
   else if (conn && conn.readyState === conn.OPEN) return;
   const url = new URL(path, location.origin);
@@ -37,7 +38,6 @@ function initConn(path: string, port: MessagePort, cookie: any) {
   console.log('Init connection for', path);
   conn?.close();
   conn = new ReconnectingWebsocket(url.toString());
-  ports.push(port);
   conn.onopen = () => {
     console.log('Connected to', path);
     broadcastMsg({ type: 'open' });
@@ -85,8 +85,8 @@ self.onconnect = function (e) { // eslint-disable-line no-undef
 
   port.addEventListener('message', (msg: { data: RequestPayload }) => {
     if (msg.data.type === 'conn') initConn(msg.data.path, port, msg.data.cookie);
-    if (msg.data.type === 'ack') ack[msg.data.id]();
-    if (msg.data.type === 'unload') ports = ports.filter((i) => i !== port);
+    if (msg.data.type === 'ack') ack[msg.data.id]?.();
+    if (msg.data.type === 'unload') ports.delete(port);
   });
 
   port.start();