Added circular JSON handling to forwardToMain (#2242)

tonyanziano · web-flow · commit e8794098bae7 · 2021-03-09T13:30:16.000-08:00
* Added circular JSON handling to forwardToMain

* Added changelog entry

* Updated changelog
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,8 +5,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## Unreleased
+## Fixed
+- [client] Added circular JSON handling to `forwardToMain.ts` which fixed a bug preventing the Emulator from connecting to Direct Line Speech bots in PR [2242](https://github.com/microsoft/BotFramework-Emulator/pull/2242)
 
-## v4.12.0 - 2021 - 3 - 04
+## v4.12.0 - 2021 - 3 - 05
 ## Added
 - [client/main] Added UI to open bot dialog that allows the user to set transcript testing properties `randomSeed` and `randomValue` in PR [2209](https://github.com/microsoft/BotFramework-Emulator/pull/2209)
 - [client] Added a dialog to the "Conversation -> Send System Activity" menu that allows the user to send custom activity payloads to their bot in PR [2213](https://github.com/microsoft/BotFramework-Emulator/pull/2213)
diff --git a/packages/app/client/src/state/middleware/forwardToMain.spec.ts b/packages/app/client/src/state/middleware/forwardToMain.spec.ts
@@ -79,4 +79,33 @@ describe('forwardToMain middleware', () => {
     expect(mockNext).toHaveBeenCalledWith(mockAction);
     expect(mockIpcRenderer.sendSync).toHaveBeenCalledWith('sync-store', mockAction);
   });
+
+  it('should skip forwarding the action to the main process if the payload has a circular structure', () => {
+    const innerObject = { outerObject: undefined };
+    const outerObject = { innerObject: undefined };
+    innerObject.outerObject = outerObject;
+    outerObject.innerObject = innerObject;
+    const mockNext = jest.fn();
+    const mockAction: any = {
+      type: 'actionType',
+      payload: { outerObject },
+    };
+    forwardToMain(null)(mockNext)(mockAction);
+
+    expect(mockNext).toHaveBeenCalledWith(mockAction);
+    expect(mockIpcRenderer.sendSync).not.toHaveBeenCalled();
+  });
+
+  it('should surface errors that are not circular JSON errors', () => {
+    const mockNext = jest.fn();
+    const mockAction: any = {
+      type: 'actionType',
+      payload: { someProp: 123 },
+    };
+    mockIpcRenderer.sendSync.mockImplementationOnce(() => {
+      throw new Error('some error >:(');
+    });
+
+    expect(() => forwardToMain(null)(mockNext)(mockAction)).toThrowError(new Error('some error >:('));
+  });
 });
diff --git a/packages/app/client/src/state/middleware/forwardToMain.ts b/packages/app/client/src/state/middleware/forwardToMain.ts
@@ -45,11 +45,20 @@ export const forwardToMain: Middleware = _store => next => action => {
     return next(action);
   }
 
-  // Electron 9 does not allow functions to be sent over ipc (https://www.electronjs.org/docs/api/ipc-renderer#ipcrenderersendchannel-args)
-  // JSON.stringify() removes function properties from objects -- these functions do not need to be maintained in the main process' copy of state
-  const processedAction = JSON.parse(JSON.stringify(action));
+  try {
+    // Electron 9 does not allow functions to be sent over ipc (https://www.electronjs.org/docs/api/ipc-renderer#ipcrenderersendchannel-args)
+    // JSON.stringify() removes function properties from objects -- these functions do not need to be maintained in the main process' copy of state
+    const processedAction = JSON.parse(JSON.stringify(action));
 
-  // forward the action over ipc to the main process
-  ipcRenderer.sendSync('sync-store', processedAction);
-  return next(action);
+    // forward the action over ipc to the main process
+    ipcRenderer.sendSync('sync-store', processedAction);
+    return next(action);
+  } catch (e) {
+    if (e.message && e.message.includes('circular structure')) {
+      // the payload of the action contains a circular JSON structure and cannot be stringified;
+      // skip forwarding the action to the main process
+      return next(action);
+    }
+    throw e;
+  }
 };
