diff --git a/packages/backend/server/src/core/sync/events/events.gateway.ts b/packages/backend/server/src/core/sync/events/events.gateway.ts
index a637675f10..b71e70278d 100644
--- a/packages/backend/server/src/core/sync/events/events.gateway.ts
+++ b/packages/backend/server/src/core/sync/events/events.gateway.ts
@@ -38,27 +38,21 @@ export const GatewayErrorWrapper = (): MethodDecorator => {
       return desc;
     }
 
-    desc.value = function (...args: any[]) {
-      let result: any;
+    desc.value = async function (...args: any[]) {
       try {
-        result = originalMethod.apply(this, args);
+        return await originalMethod.apply(this, args);
       } catch (e) {
-        metrics.socketio.counter('unhandled_errors').add(1);
-        return {
-          error: new InternalError(e as Error),
-        };
-      }
-
-      if (result instanceof Promise) {
-        return result.catch(e => {
-          metrics.socketio.counter('unhandled_errors').add(1);
-          new Logger('EventsGateway').error(e, e.stack);
+        if (e instanceof EventError) {
           return {
-            error: new InternalError(e),
+            error: e,
           };
-        });
-      } else {
-        return result;
+        } else {
+          metrics.socketio.counter('unhandled_errors').add(1);
+          new Logger('EventsGateway').error(e, (e as Error).stack);
+          return {
+            error: new InternalError(e as Error),
+          };
+        }
       }
     };
 
@@ -85,6 +79,14 @@ type EventResponse<Data = any> =
           data: Data;
         });
 
+function Sync(workspaceId: string): `${string}:sync` {
+  return `${workspaceId}:sync`;
+}
+
+function Awareness(workspaceId: string): `${string}:awareness` {
+  return `${workspaceId}:awareness`;
+}
+
 @WebSocketGateway({
   cors: !AFFiNE.node.prod,
   transports: ['websocket'],
@@ -113,7 +115,7 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     metrics.socketio.gauge('realtime_connections').record(this.connectionCount);
   }
 
-  checkVersion(client: Socket, version?: string) {
+  assertVersion(client: Socket, version?: string) {
     if (
       // @todo(@darkskygit): remove this flag after 0.12 goes stable
       AFFiNE.featureFlags.syncClientVersionCheck &&
@@ -126,14 +128,48 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
           version ? ` ${version}` : ''
         } is outdated, please update to ${AFFiNE.version}`,
       });
-      return {
-        error: new EventError(
-          EventErrorCode.VERSION_REJECTED,
-          `Client version ${version} is outdated, please update to ${AFFiNE.version}`
-        ),
-      };
+
+      throw new EventError(
+        EventErrorCode.VERSION_REJECTED,
+        `Client version ${version} is outdated, please update to ${AFFiNE.version}`
+      );
+    }
+  }
+
+  async joinWorkspace(
+    client: Socket,
+    room: `${string}:${'sync' | 'awareness'}`
+  ) {
+    await client.join(room);
+  }
+
+  async leaveWorkspace(
+    client: Socket,
+    room: `${string}:${'sync' | 'awareness'}`
+  ) {
+    await client.leave(room);
+  }
+
+  assertInWorkspace(client: Socket, room: `${string}:${'sync' | 'awareness'}`) {
+    if (!client.rooms.has(room)) {
+      throw new NotInWorkspaceError(room);
+    }
+  }
+
+  async assertWorkspaceAccessible(
+    workspaceId: string,
+    userId: string,
+    permission: Permission = Permission.Read
+  ) {
+    if (
+      !(await this.permissions.isWorkspaceMember(
+        workspaceId,
+        userId,
+        permission
+      ))
+    ) {
+      throw new AccessDeniedError(workspaceId);
     }
-    return null;
   }
 
   @Auth()
@@ -144,29 +180,19 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     @MessageBody('version') version: string | undefined,
     @ConnectedSocket() client: Socket
   ): Promise<EventResponse<{ clientId: string }>> {
-    const versionError = this.checkVersion(client, version);
-    if (versionError) {
-      return versionError;
-    }
-
-    const canWrite = await this.permissions.tryCheckWorkspace(
+    this.assertVersion(client, version);
+    await this.assertWorkspaceAccessible(
       workspaceId,
       user.id,
       Permission.Write
     );
 
-    if (canWrite) {
-      await client.join(`${workspaceId}:sync`);
-      return {
-        data: {
-          clientId: client.id,
-        },
-      };
-    } else {
-      return {
-        error: new AccessDeniedError(workspaceId),
-      };
-    }
+    await this.joinWorkspace(client, Sync(workspaceId));
+    return {
+      data: {
+        clientId: client.id,
+      },
+    };
   }
 
   @Auth()
@@ -177,47 +203,18 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     @MessageBody('version') version: string | undefined,
     @ConnectedSocket() client: Socket
   ): Promise<EventResponse<{ clientId: string }>> {
-    const versionError = this.checkVersion(client, version);
-    if (versionError) {
-      return versionError;
-    }
-
-    const canWrite = await this.permissions.tryCheckWorkspace(
+    this.assertVersion(client, version);
+    await this.assertWorkspaceAccessible(
       workspaceId,
       user.id,
       Permission.Write
     );
 
-    if (canWrite) {
-      await client.join(`${workspaceId}:awareness`);
-      return {
-        data: {
-          clientId: client.id,
-        },
-      };
-    } else {
-      return {
-        error: new AccessDeniedError(workspaceId),
-      };
-    }
-  }
-
-  /**
-   * @deprecated use `client-handshake-sync` and `client-handshake-awareness` instead
-   */
-  @Auth()
-  @SubscribeMessage('client-handshake')
-  async handleClientHandShake(
-    @MessageBody() workspaceId: string,
-    @ConnectedSocket() client: Socket
-  ): Promise<EventResponse<{ clientId: string }>> {
-    const versionError = this.checkVersion(client);
-    if (versionError) {
-      return versionError;
-    }
-    // should unreachable
+    await this.joinWorkspace(client, Awareness(workspaceId));
     return {
-      error: new AccessDeniedError(workspaceId),
+      data: {
+        clientId: client.id,
+      },
     };
   }
 
@@ -226,14 +223,9 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     @MessageBody() workspaceId: string,
     @ConnectedSocket() client: Socket
   ): Promise<EventResponse> {
-    if (client.rooms.has(`${workspaceId}:sync`)) {
-      await client.leave(`${workspaceId}:sync`);
-      return {};
-    } else {
-      return {
-        error: new NotInWorkspaceError(workspaceId),
-      };
-    }
+    this.assertInWorkspace(client, Sync(workspaceId));
+    await this.leaveWorkspace(client, Sync(workspaceId));
+    return {};
   }
 
   @SubscribeMessage('client-leave-awareness')
@@ -241,14 +233,9 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     @MessageBody() workspaceId: string,
     @ConnectedSocket() client: Socket
   ): Promise<EventResponse> {
-    if (client.rooms.has(`${workspaceId}:awareness`)) {
-      await client.leave(`${workspaceId}:awareness`);
-      return {};
-    } else {
-      return {
-        error: new NotInWorkspaceError(workspaceId),
-      };
-    }
+    this.assertInWorkspace(client, Awareness(workspaceId));
+    await this.leaveWorkspace(client, Awareness(workspaceId));
+    return {};
   }
 
   @SubscribeMessage('client-pre-sync')
@@ -257,11 +244,7 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     @MessageBody()
     { workspaceId, timestamp }: { workspaceId: string; timestamp?: number }
   ): Promise<EventResponse<Record<string, number>>> {
-    if (!client.rooms.has(`${workspaceId}:sync`)) {
-      return {
-        error: new NotInWorkspaceError(workspaceId),
-      };
-    }
+    this.assertInWorkspace(client, Sync(workspaceId));
 
     const stats = await this.docManager.getStats(workspaceId, timestamp);
 
@@ -284,11 +267,7 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     },
     @ConnectedSocket() client: Socket
   ): Promise<EventResponse<{ accepted: true; timestamp?: number }>> {
-    if (!client.rooms.has(`${workspaceId}:sync`)) {
-      return {
-        error: new NotInWorkspaceError(workspaceId),
-      };
-    }
+    this.assertInWorkspace(client, Sync(workspaceId));
 
     const docId = new DocID(guid, workspaceId);
     const buffers = updates.map(update => Buffer.from(update, 'base64'));
@@ -299,7 +278,7 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     );
 
     client
-      .to(`${docId.workspace}:sync`)
+      .to(Sync(workspaceId))
       .emit('server-updates', { workspaceId, guid, updates, timestamp });
 
     return {
@@ -310,11 +289,9 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     };
   }
 
-  @Auth()
   @SubscribeMessage('doc-load-v2')
   async loadDocV2(
     @ConnectedSocket() client: Socket,
-    @CurrentUser() user: CurrentUser,
     @MessageBody()
     {
       workspaceId,
@@ -326,17 +303,7 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
       stateVector?: string;
     }
   ): Promise<EventResponse<{ missing: string; state?: string }>> {
-    if (!client.rooms.has(`${workspaceId}:sync`)) {
-      const canRead = await this.permissions.tryCheckWorkspace(
-        workspaceId,
-        user.id
-      );
-      if (!canRead) {
-        return {
-          error: new AccessDeniedError(workspaceId),
-        };
-      }
-    }
+    this.assertInWorkspace(client, Sync(workspaceId));
 
     const docId = new DocID(guid, workspaceId);
     const doc = await this.docManager.get(docId.workspace, docId.guid);
@@ -363,40 +330,33 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     };
   }
 
-  @Auth()
   @SubscribeMessage('awareness-init')
   async handleInitAwareness(
     @MessageBody() workspaceId: string,
     @ConnectedSocket() client: Socket
   ): Promise<EventResponse<{ clientId: string }>> {
-    if (client.rooms.has(`${workspaceId}:awareness`)) {
-      client.to(`${workspaceId}:awareness`).emit('new-client-awareness-init');
-      return {
-        data: {
-          clientId: client.id,
-        },
-      };
-    } else {
-      return {
-        error: new NotInWorkspaceError(workspaceId),
-      };
-    }
+    this.assertInWorkspace(client, Awareness(workspaceId));
+    client.to(Awareness(workspaceId)).emit('new-client-awareness-init');
+    return {
+      data: {
+        clientId: client.id,
+      },
+    };
   }
 
   @SubscribeMessage('awareness-update')
   async handleHelpGatheringAwareness(
-    @MessageBody() message: { workspaceId: string; awarenessUpdate: string },
+    @MessageBody()
+    {
+      workspaceId,
+      awarenessUpdate,
+    }: { workspaceId: string; awarenessUpdate: string },
     @ConnectedSocket() client: Socket
   ): Promise<EventResponse> {
-    if (client.rooms.has(`${message.workspaceId}:awareness`)) {
-      client
-        .to(`${message.workspaceId}:awareness`)
-        .emit('server-awareness-broadcast', message);
-      return {};
-    } else {
-      return {
-        error: new NotInWorkspaceError(message.workspaceId),
-      };
-    }
+    this.assertInWorkspace(client, Awareness(workspaceId));
+    client
+      .to(Awareness(workspaceId))
+      .emit('server-awareness-broadcast', { workspaceId, awarenessUpdate });
+    return {};
   }
 }
diff --git a/packages/backend/server/src/core/workspaces/permission.ts b/packages/backend/server/src/core/workspaces/permission.ts
index c188e1166b..1c750c73f9 100644
--- a/packages/backend/server/src/core/workspaces/permission.ts
+++ b/packages/backend/server/src/core/workspaces/permission.ts
@@ -73,6 +73,28 @@ export class PermissionService {
     return this.tryCheckPage(ws, id, user);
   }
 
+  /**
+   * Returns whether a given user is a member of a workspace and has the given or higher permission.
+   */
+  async isWorkspaceMember(
+    ws: string,
+    user: string,
+    permission: Permission
+  ): Promise<boolean> {
+    const count = await this.prisma.workspaceUserPermission.count({
+      where: {
+        workspaceId: ws,
+        userId: user,
+        accepted: true,
+        type: {
+          gte: permission,
+        },
+      },
+    });
+
+    return count !== 0;
+  }
+
   async checkWorkspace(
     ws: string,
     user?: string,
diff --git a/packages/backend/server/src/fundamentals/metrics/utils.ts b/packages/backend/server/src/fundamentals/metrics/utils.ts
index e4d16a3492..83bcd1856c 100644
--- a/packages/backend/server/src/fundamentals/metrics/utils.ts
+++ b/packages/backend/server/src/fundamentals/metrics/utils.ts
@@ -18,11 +18,16 @@ export const CallTimer = (
       return desc;
     }
 
-    desc.value = function (...args: any[]) {
+    desc.value = async function (...args: any[]) {
       const timer = metrics[scope].histogram(name, {
         description: `function call time costs of ${name}`,
         unit: 'ms',
       });
+      metrics[scope]
+        .counter(`${name}_calls`, {
+          description: `function call counts of ${name}`,
+        })
+        .add(1, attrs);
 
       const start = Date.now();
 
@@ -30,19 +35,10 @@ export const CallTimer = (
         timer.record(Date.now() - start, attrs);
       };
 
-      let result: any;
       try {
-        result = originalMethod.apply(this, args);
-      } catch (e) {
+        return await originalMethod.apply(this, args);
+      } finally {
         end();
-        throw e;
-      }
-
-      if (result instanceof Promise) {
-        return result.finally(end);
-      } else {
-        end();
-        return result;
       }
     };
 
diff --git a/packages/frontend/workspace-impl/src/cloud/awareness.ts b/packages/frontend/workspace-impl/src/cloud/awareness.ts
index 450ae25972..431c5e1855 100644
--- a/packages/frontend/workspace-impl/src/cloud/awareness.ts
+++ b/packages/frontend/workspace-impl/src/cloud/awareness.ts
@@ -104,7 +104,7 @@ export class AffineCloudAwarenessProvider implements AwarenessProvider {
     uint8ArrayToBase64(awarenessUpdate)
       .then(encodedAwarenessUpdate => {
         this.socket.emit('awareness-update', {
-          guid: this.workspaceId,
+          workspaceId: this.workspaceId,
           awarenessUpdate: encodedAwarenessUpdate,
         });
       })
@@ -120,11 +120,19 @@ export class AffineCloudAwarenessProvider implements AwarenessProvider {
   };
 
   handleConnect = () => {
-    this.socket.emit('client-handshake-awareness', {
-      workspaceId: this.workspaceId,
-      version: runtimeConfig.appVersion,
-    });
-    this.socket.emit('awareness-init', this.workspaceId);
+    this.socket.emit(
+      'client-handshake-awareness',
+      {
+        workspaceId: this.workspaceId,
+        version: runtimeConfig.appVersion,
+      },
+      (res: any) => {
+        logger.debug('awareness handshake finished', res);
+        this.socket.emit('awareness-init', this.workspaceId, (res: any) => {
+          logger.debug('awareness-init finished', res);
+        });
+      }
+    );
   };
 
   handleReject = (_msg: RejectByVersion) => {
diff --git a/packages/frontend/workspace-impl/src/cloud/sync.ts b/packages/frontend/workspace-impl/src/cloud/sync.ts
index 1ce7349640..ca14d2f17b 100644
--- a/packages/frontend/workspace-impl/src/cloud/sync.ts
+++ b/packages/frontend/workspace-impl/src/cloud/sync.ts
@@ -42,10 +42,16 @@ export class AffineSyncStorage implements SyncStorage {
   }
 
   handleConnect = () => {
-    this.socket.emit('client-handshake-sync', {
-      workspaceId: this.workspaceId,
-      version: runtimeConfig.appVersion,
-    });
+    this.socket.emit(
+      'client-handshake-sync',
+      {
+        workspaceId: this.workspaceId,
+        version: runtimeConfig.appVersion,
+      },
+      (res: any) => {
+        logger.debug('client handshake finished', res);
+      }
+    );
   };
 
   handleReject = (message: RejectByVersion) => {