Use postMessage between page/content (#31)

packages/extension/src/events.ts

@@ -1,14 +0,0 @@
-// Copyright 2019 @polkadot/extension authors & contributors
-// This software may be modified and distributed under the terms
-// of the Apache-2.0 license. See the LICENSE file for details.
-
-const eventTarget = document;
-
-const events = {
-  request: 'PolkadotJsWebRequest',
-  response: 'PolkadotJsWebResponse'
-};
-
-export { eventTarget };
-
-export default events;

packages/extension/src/inject/index.ts

@@ -5,7 +5,6 @@
 import { InjectedWindow } from '@polkadot/extension-dapp/types';
 import { MessageTypes } from '../background/types';
 
-import events, { eventTarget } from '../events';
 import Injected from './Injected';
 
 // when sending a message from the injector to the expension, we
@@ -27,17 +26,15 @@ const windowInject = window as InjectedWindow;
 const callbacks: Callbacks = {};
 let idCounter = 0;
 
-// a generic message sender that creates an event, returning a promise that will resolve once
-// the event is resolved (by the response listener just below this)
+// a generic message sender that creates an event, returning a promise that will
+// resolve once the event is resolved (by the response listener just below this)
 function sendMessage (message: MessageTypes, request: any = null): Promise<any> {
   return new Promise((resolve, reject) => {
     const id = ++idCounter;
 
     callbacks[id] = { resolve, reject };
 
-    eventTarget.dispatchEvent(
-      new CustomEvent(events.request, { detail: { id, message, request } })
-    );
+    window.postMessage({ id, message, origin: 'inject', request }, '*');
   });
 }
 
@@ -49,21 +46,25 @@ async function enable (origin: string): Promise<Injected> {
 }
 
 // setup a response listener (events created by the loader for extension responses)
-eventTarget.addEventListener(events.response, (event) => {
-  const response = (event as CustomEvent).detail;
-  const promise = callbacks[response.id];
-
-  if (!promise) {
-    console.error(`Uknown response: ${JSON.stringify(response)}`);
+window.addEventListener('message', ({ data, source }) => {
+  // only allow messages from our window, by the loader
+  if (source !== window || data.origin !== 'loader') {
     return;
   }
 
-  delete callbacks[response.id];
+  const promise = callbacks[data.id];
 
-  if (response.error) {
-    promise.reject(new Error(response.error));
+  if (!promise) {
+    console.error(`Uknown response: ${JSON.stringify(data)}`);
+    return;
+  }
+
+  delete callbacks[data.id];
+
+  if (data.error) {
+    promise.reject(new Error(data.error));
   } else {
-    promise.resolve(response.response);
+    promise.resolve(data.response);
   }
 });
 

packages/extension/src/loader.ts

@@ -4,23 +4,22 @@
 
 import extension from 'extensionizer';
 
-import events, { eventTarget } from './events';
-
-function sendResponse (detail: any): void {
-  // create the custom event, this will be handled on the injection script
-  eventTarget.dispatchEvent(new CustomEvent(events.response, { detail }));
+function sendResponse (data: any): void {
+  window.postMessage({ ...data, origin: 'loader' }, '*');
 }
 
-// Handle all custom events, passing messages to the extension
-eventTarget.addEventListener(events.request, (event) => {
-  // get the request as part of the the event detailt
-  const request = (event as CustomEvent).detail;
+// Handle all messages, passing messages to the extension
+window.addEventListener('message', ({ data, source }) => {
+  // only allow messages from our window, by the inject
+  if (source !== window || data.origin !== 'inject') {
+    return;
+  }
 
   // pass the detail as-is as a message to the extension
-  extension.runtime.sendMessage(request, (response) => {
+  extension.runtime.sendMessage(data, (response) => {
     if (!response) {
       // no data, send diconnected/unknown error
-      sendResponse({ id: request.id, error: 'Unknown response' });
+      sendResponse({ id: data.id, error: 'Unknown response' });
     } else {
       // handle the response, passing as a custom event
       sendResponse(response);