From 33e527f39ace8265f50a0a720ec23f82054a249b Mon Sep 17 00:00:00 2001
From: Michel Weststrate <mweststrate@fb.com>
Date: Mon, 16 Nov 2020 13:08:05 -0800
Subject: [PATCH] Add `onUnhandledMesssage` handler

Summary: This diff adds the `client.onUnhandledMessage` handler, to be able to handle messages for which we don't know the names upfront. Some existing plugins that only send one kind of message can benefit from this, as can generic plugins, like the createTablePlugin

Reviewed By: passy

Differential Revision: D24949453

fbshipit-source-id: 0fed81e28aee350632c09ee3bb834f306dc8b100
---
 .../flipper-plugin/src/__tests__/TestPlugin.tsx  |  7 +++++++
 .../src/__tests__/test-utils.node.tsx            |  9 +++++++++
 desktop/flipper-plugin/src/plugin/Plugin.tsx     | 16 +++++++++++++++-
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/desktop/flipper-plugin/src/__tests__/TestPlugin.tsx b/desktop/flipper-plugin/src/__tests__/TestPlugin.tsx
index 433ac5fed..8c0c557b8 100644
--- a/desktop/flipper-plugin/src/__tests__/TestPlugin.tsx
+++ b/desktop/flipper-plugin/src/__tests__/TestPlugin.tsx
@@ -36,6 +36,7 @@ export function plugin(client: PluginClient<Events, Methods>) {
       persist: 'counter',
     },
   );
+  const unhandledMessages = createState<any[]>([]);
 
   client.onConnect(connectStub);
   client.onDisconnect(disconnectStub);
@@ -47,6 +48,11 @@ export function plugin(client: PluginClient<Events, Methods>) {
       draft.count += delta;
     });
   });
+  client.onUnhandledMessage((event, params) => {
+    unhandledMessages.update((draft) => {
+      draft.push({event, params});
+    });
+  });
 
   function _unused_JustTypeChecks() {
     // @ts-expect-error Argument of type '"bla"' is not assignable
@@ -77,6 +83,7 @@ export function plugin(client: PluginClient<Events, Methods>) {
     disconnectStub,
     getCurrentState,
     state,
+    unhandledMessages,
     appId: client.appId,
     appName: client.appName,
   };
diff --git a/desktop/flipper-plugin/src/__tests__/test-utils.node.tsx b/desktop/flipper-plugin/src/__tests__/test-utils.node.tsx
index 0ad83cb8b..cd222bc06 100644
--- a/desktop/flipper-plugin/src/__tests__/test-utils.node.tsx
+++ b/desktop/flipper-plugin/src/__tests__/test-utils.node.tsx
@@ -180,6 +180,15 @@ test('a plugin can receive messages', async () => {
       },
     }
   `);
+
+  expect(instance.unhandledMessages.get().length).toBe(0);
+  sendEvent('unhandled' as any, {hello: 'world'});
+  expect(instance.unhandledMessages.get()).toEqual([
+    {
+      event: 'unhandled',
+      params: {hello: 'world'},
+    },
+  ]);
 });
 
 test('plugins support non-serializable state', async () => {
diff --git a/desktop/flipper-plugin/src/plugin/Plugin.tsx b/desktop/flipper-plugin/src/plugin/Plugin.tsx
index 3fdf08400..2b3d1ac97 100644
--- a/desktop/flipper-plugin/src/plugin/Plugin.tsx
+++ b/desktop/flipper-plugin/src/plugin/Plugin.tsx
@@ -63,6 +63,13 @@ export interface PluginClient<
     callback: (params: Events[Event]) => void,
   ): void;
 
+  /**
+   * Subscribe to all messages arriving from the devices not handled by another listener.
+   *
+   * This handler is untyped, and onMessage should be favored over using onUnhandledMessage if the event name is known upfront.
+   */
+  onUnhandledMessage(callback: (event: string, params: any) => void): void;
+
   /**
    * Send a message to the connected client
    */
@@ -156,6 +163,9 @@ export class SandyPluginInstance extends BasePluginInstance {
       onMessage: (event, callback) => {
         this.events.on('event-' + event, callback);
       },
+      onUnhandledMessage: (callback) => {
+        this.events.on('unhandled-event', callback);
+      },
       supportsMethod: async (method) => {
         this.assertConnected();
         return await realClient.supportsMethod(
@@ -212,7 +222,11 @@ export class SandyPluginInstance extends BasePluginInstance {
 
   receiveMessages(messages: Message[]) {
     messages.forEach((message) => {
-      this.events.emit('event-' + message.method, message.params);
+      if (this.events.listenerCount('event-' + message.method) > 0) {
+        this.events.emit('event-' + message.method, message.params);
+      } else {
+        this.events.emit('unhandled-event', message.method, message.params);
+      }
     });
   }