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200 lines
5.5 KiB
200 lines
5.5 KiB
import { IWorkerController, WorkerMessageType, IWorkerMessage } from './worker.core'; |
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const COMMUNICATION_TIMEOUT = 30000; |
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/** |
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* 通信通道 |
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*/ |
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export class WorkerChannel { |
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/** |
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* Web Worker 实例 |
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*/ |
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private worker: Worker; |
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/** |
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* 上层通信控制器 |
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*/ |
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private controller: IWorkerController; |
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/** |
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* 会话响应器 Map |
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*/ |
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private sessionHandlerMap: { |
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[propsName: string]: Function; |
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}; |
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public constructor(worker: Worker, controller: IWorkerController) { |
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this.worker = worker; |
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this.controller = controller; |
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this.sessionHandlerMap = {}; |
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// 绑定 worker onmessage 事件的回调 |
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this.worker.addEventListener('message', this.onmessage.bind(this)); |
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} |
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/** |
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* 发送响应 |
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* |
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* @param sessionId 会话 Id |
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* @param payload 负载 |
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*/ |
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public response(sessionId: string, actionType: string, payload: any): void { |
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this.postMessage({ |
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messageType: WorkerMessageType.REPLY, |
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actionType, |
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payload, |
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sessionId, |
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}); |
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} |
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/** |
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* 发送请求, 不等待响应 |
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* |
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* @param actionType 事务类型 |
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* @param payload 负载 |
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*/ |
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public request(actionType: string, payload: any): void { |
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const sessionId = this.generateSessionId(); |
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this.postMessage({ |
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messageType: WorkerMessageType.REQUEST, |
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actionType, |
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payload, |
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sessionId, |
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}); |
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// 不等待结果, 还会收到响应, 添加个空的会话响应器 |
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this.addSessionHandler(sessionId, () => {}); |
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} |
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/** |
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* 发送请求, 并等待响应 |
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* |
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* @param actionType 事务类型 |
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* @param payload 负载 |
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* @param timeout 响应超时 |
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* @returns {Promise<IWorkerMessage>} 等待响应的 Promise |
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*/ |
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public requestPromise<T>(actionType: string, payload: any, timeout = COMMUNICATION_TIMEOUT): Promise<T> { |
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const sessionId = this.generateSessionId(); |
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const message = { |
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messageType: WorkerMessageType.REQUEST, |
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actionType, |
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payload, |
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sessionId, |
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}; |
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// 请求封装为一个 Promise, 等待会话响应器进行 resolve |
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const PromiseFunction = (resolve: Function, reject: Function): any => { |
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// 启动请求超时计时器 |
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const timeoutHandler = setTimeout(() => { |
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clearTimeout(timeoutHandler); |
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reject(); |
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}, timeout); |
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const sessionHandler: Function = (message: IWorkerMessage) => { |
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// 会话回调函数, 开始处理响应 |
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this.deleteSessionHandler(message.sessionId); |
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clearTimeout(timeoutHandler); |
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resolve(message.payload); |
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}; |
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this.addSessionHandler(sessionId, sessionHandler); |
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// 开始发送请求 |
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this.postMessage(message); |
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}; |
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return new Promise(PromiseFunction); |
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} |
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/** |
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* 收到会话消息的处理函数 |
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* |
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* 发现是请求, 调用通信控制器的事务处理器进行处理, 获取事务结果并响应; |
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* 发现是响应,调用会话响应器 |
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* @param event worker 通信事件 |
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*/ |
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private onmessage(event: { data: IWorkerMessage }): void { |
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const { data: message } = event; |
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const { messageType, sessionId, actionType } = message; |
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// 接收到请求 |
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if (messageType === WorkerMessageType.REQUEST) { |
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// 处理请求 |
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this.controller.actionHandler(message) |
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.then(actionResult => { |
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// 响应请求 |
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this.response(sessionId, actionType, actionResult); |
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}); |
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} |
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// 接收到响应 |
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if (messageType === WorkerMessageType.REPLY) { |
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// 处理响应 |
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if (this.hasSessionHandler(sessionId)) { |
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this.sessionHandlerMap[sessionId](message); |
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} else { |
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throw new Error(`Session \`${sessionId}\` handler no exist`); |
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} |
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} |
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} |
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/** |
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* 封装的 worker 原生 postMessage 接口 |
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* 支持 structured clone 和 transfer 2种通信模式 |
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* |
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* @param message 会话消息 |
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*/ |
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private postMessage(message: IWorkerMessage): void { |
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this.worker.postMessage(message); |
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} |
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/** |
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* 添加会话响应器 |
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* |
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* @param sessionId 会话 Id |
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* @param handler 会话响应器 |
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*/ |
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private addSessionHandler(sessionId: string, handler: Function): void { |
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if (!this.hasSessionHandler(sessionId)) { |
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this.sessionHandlerMap[sessionId] = handler; |
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} else { |
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throw new Error(`SessionId \`${sessionId}\` already exist!`); |
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} |
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} |
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/** |
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* 移除会话响应器 |
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* |
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* @param sessionId |
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*/ |
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private deleteSessionHandler(sessionId: string): void { |
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if (this.hasSessionHandler(sessionId)) { |
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delete this.sessionHandlerMap[sessionId]; |
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} |
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} |
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/** |
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* 生成每次独立会话的 Id |
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* |
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* @returns 会话 Id |
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*/ |
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private generateSessionId(): string { |
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const sessionId = `w_${BI.UUID()}`; |
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return sessionId; |
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} |
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/** |
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* 判断是否有指定会话的处理器 |
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* |
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* @param sessionId 会话 Id |
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* @returns {boolean} 判断结果 |
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*/ |
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private hasSessionHandler(sessionId: string): boolean { |
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return !!this.sessionHandlerMap[sessionId]; |
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} |
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}
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