79 lines
2.4 KiB
TypeScript
79 lines
2.4 KiB
TypeScript
// Copyright 2019 @polkadot/extension authors & contributors
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// This software may be modified and distributed under the terms
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// of the Apache-2.0 license. See the LICENSE file for details.
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import { InjectedWindow } from '@polkadot/extension-dapp/types';
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import { MessageTypes } from '../background/types';
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import Injected from './Injected';
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// when sending a message from the injector to the expension, we
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// - create an event - this we send to the loader
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// - the loader takes this evend and uses sendMessage to the extension background
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// - on respoinse, the loader creates a reponse event
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// - this injector, reads listends on the events, maps it to the original
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// - resolves/rejects the promise with the result
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type Handlers = {
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[index: number]: {
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resolve: (data: any) => void,
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reject: (error: Error) => void
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}
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};
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// small helper with the typescript types, just cast window
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const windowInject = window as InjectedWindow;
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const handlers: Handlers = {};
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let idCounter = 0;
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// a generic message sender that creates an event, returning a promise that will
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// resolve once the event is resolved (by the response listener just below this)
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function sendMessage (message: MessageTypes, request: any = null): Promise<any> {
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return new Promise((resolve, reject) => {
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const id = ++idCounter;
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handlers[id] = { resolve, reject };
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window.postMessage({ id, message, origin: 'page', request }, '*');
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});
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}
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// the enable function, called by the dapp to allow access
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async function enable (origin: string): Promise<Injected> {
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await sendMessage('authorize.tab', { origin });
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return new Injected(sendMessage);
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}
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// setup a response listener (events created by the loader for extension responses)
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window.addEventListener('message', ({ data, source }) => {
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// only allow messages from our window, by the loader
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if (source !== window || data.origin !== 'content') {
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return;
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}
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const handler = handlers[data.id];
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if (!handler) {
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console.error(`Uknown response: ${JSON.stringify(data)}`);
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return;
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}
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delete handlers[data.id];
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if (data.error) {
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handler.reject(new Error(data.error));
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} else {
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handler.resolve(data.response);
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}
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});
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// don't clobber the existing object, we will add it it (or create as needed)
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windowInject.injectedWeb3 = windowInject.injectedWeb3 || {};
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// add our enable function
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windowInject.injectedWeb3['polkadot-js'] = {
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enable,
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version: process.env.PKG_VERSION as string
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};
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