From f0234bbbed4b9ddab0f630cde5ee8966ebdf2363 Mon Sep 17 00:00:00 2001
From: Wenzhao Hu <wzhudev@gmail.com>
Date: Tue, 26 Nov 2024 19:13:43 +0800
Subject: [PATCH] fix: fix client may miss the INITIALIZE event (#4158)

---
 .../rpc/src/services/rpc/channel.service.ts   |  3 +-
 packages/rpc/src/services/rpc/rpc.service.ts  | 30 ++++++++++++++-----
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/packages/rpc/src/services/rpc/channel.service.ts b/packages/rpc/src/services/rpc/channel.service.ts
index 5de377bc72..25c56163f6 100644
--- a/packages/rpc/src/services/rpc/channel.service.ts
+++ b/packages/rpc/src/services/rpc/channel.service.ts
@@ -15,9 +15,8 @@
  */
 
 import type { IDisposable } from '@univerjs/core';
-import { createIdentifier } from '@univerjs/core';
-
 import type { IChannel, IMessageProtocol } from './rpc.service';
+import { createIdentifier } from '@univerjs/core';
 import { ChannelClient, ChannelServer } from './rpc.service';
 
 export interface IRPCChannelService {
diff --git a/packages/rpc/src/services/rpc/rpc.service.ts b/packages/rpc/src/services/rpc/rpc.service.ts
index e03eb5b031..b53f3c4f67 100644
--- a/packages/rpc/src/services/rpc/rpc.service.ts
+++ b/packages/rpc/src/services/rpc/rpc.service.ts
@@ -122,14 +122,22 @@ export interface IChannelClient {
     getChannel<T extends IChannel>(channelName: string): T;
 }
 
-/**
- *
- */
 export interface IChannelServer {
     registerChannel<T extends IChannel>(channelName: string, channel: T): void;
 }
 
 enum RequestType {
+    /**
+     * In Univer, we cannot make sure that when IPCServer constructs, the process (or thread)
+     * where the corresponding IPCClient residents has bootstrapped and been ready to recieve messages.
+     * This may result in the IPCClient hanging there, waiting for the `INITIALIZE` message that it has
+     * already missed. So the client should send a REQUEST_INITIALIZATION in case of that.
+     *
+     * Later, we may want a more sophisticated RPC system where the server can serve more than
+     * one clients, and this event may be removed.
+     */
+    REQUEST_INITIALIZATION = 50,
+
     /** A simple remote calling wrapper in a Promise. */
     CALL = 100,
 
@@ -168,7 +176,8 @@ interface IRPCResponse {
     /** It should be the same as its corresponding requests' `seq`. */
     seq: number;
     type: ResponseType;
-    data?: any;
+
+    data?: any; // TODO: replace it with ISerializable.
 }
 
 interface IResponseHandler {
@@ -187,8 +196,7 @@ export class ChannelClient extends RxDisposable implements IChannelClient {
     constructor(private readonly _protocol: IMessageProtocol) {
         super();
 
-        // TODO: subscribe to the state of the protocol and see if it is connected \
-        // and initialized.
+        this._protocol.send({ type: RequestType.REQUEST_INITIALIZATION });
         this._protocol.onMessage.pipe(takeUntil(this.dispose$)).subscribe((message) => this._onMessage(message));
     }
 
@@ -334,7 +342,7 @@ export class ChannelServer extends RxDisposable implements IChannelServer {
         super();
 
         this._protocol.onMessage.pipe(takeUntil(this.dispose$)).subscribe((message) => this._onRequest(message));
-        this._sendResponse({ seq: -1, type: ResponseType.INITIALIZE });
+        this._sendInitialize();
     }
 
     override dispose(): void {
@@ -350,6 +358,9 @@ export class ChannelServer extends RxDisposable implements IChannelServer {
 
     private _onRequest(request: IRPCRequest): void {
         switch (request.type) {
+            case RequestType.REQUEST_INITIALIZATION:
+                this._sendInitialize();
+                break;
             case RequestType.CALL:
                 this._onMethodCall(request);
                 break;
@@ -364,6 +375,10 @@ export class ChannelServer extends RxDisposable implements IChannelServer {
         }
     }
 
+    private _sendInitialize(): void {
+        this._sendResponse({ seq: -1, type: ResponseType.INITIALIZE });
+    }
+
     private _onMethodCall(request: IRPCRequest): void {
         const { channelName, method, args } = request;
         const channel = this._channels.get(channelName);
@@ -436,3 +451,4 @@ export class ChannelServer extends RxDisposable implements IChannelServer {
         this._protocol.send(response);
     }
 }
+