From fcb89b94b59252b3bf63adac83b59d88df207a99 Mon Sep 17 00:00:00 2001
From: John Knox <jknox@fb.com>
Date: Mon, 27 Apr 2020 07:11:50 -0700
Subject: [PATCH] Fix wss connection initialisation race

Summary:
The websocket server has a race condition where it only starts listening for messages after the client has finished setting up.
This lets it queue up messages if the client isn't ready.

Reviewed By: passy

Differential Revision: D21256218

fbshipit-source-id: fa8481e11225cc473f03f3afbf4d0c50a48cec91
---
 desktop/app/src/server.tsx | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/desktop/app/src/server.tsx b/desktop/app/src/server.tsx
index 8bf4b6eff..52ec3a974 100644
--- a/desktop/app/src/server.tsx
+++ b/desktop/app/src/server.tsx
@@ -193,6 +193,7 @@ class Server extends EventEmitter {
           case 'connect': {
             const app = message.app;
             const plugins = message.plugins;
+            let resolvedClient: Client | null = null;
             const client = this.addConnection(
               new WebsocketClientFlipperConnection(ws, app, plugins),
               {
@@ -203,15 +204,18 @@ class Server extends EventEmitter {
                 sdk_version: 1,
               },
               {},
-            );
+            ).then((c) => (resolvedClient = c));
             clients[app] = client;
-            client.then((c) => {
-              ws.on('message', (m: any) => {
-                const parsed = JSON.parse(m.toString());
-                if (parsed.app === app) {
-                  c.onMessage(JSON.stringify(parsed.payload));
+
+            ws.on('message', (m: any) => {
+              const parsed = JSON.parse(m.toString());
+              if (parsed.app === app) {
+                const message = JSON.stringify(parsed.payload);
+                if (resolvedClient) {
+                  resolvedClient.onMessage(message);
                 }
-              });
+                client.then((c) => c.onMessage(message));
+              }
             });
             break;
           }