前端实现websocket类封装

随着Web应用程序的发展，越来越多的人开始利用Websocket技术来构建实时应用程序。Websocket是一种在客户端和服务器之间建立持久连接的协议。这种协议可以在一个单独的连接上实现双向通信。与HTTP请求-响应模型不同，Websocket允许服务器自主地向客户端发送数据。这种实时连接的能力使得Websocket在许多应用场景中得到了广泛的应用。

Websocket技术的优点之一是减少了网络延迟。在传统的HTTP请求-响应模型中，客户端必须不断地向服务器发送请求以获取更新的数据。这种不断的请求-响应循环会占用大量的带宽和处理能力。而Websocket的持久连接可以在服务器有新数据时立即向客户端发送，从而减少了网络延迟和服务器负载。

另一个优点是Websocket可以处理大量的并发连接。在传统的HTTP请求-响应模型中，每个请求都必须在服务器上进行处理，这可能会对服务器造成负载压力。但是，Websocket的持久连接可以在服务器上保持打开状态，从而减少了与每个连接相关的开销。这使得服务器可以处理大量的并发连接而不会降低性能。

Websocket还可以用于实时通信。例如，聊天应用程序可以使用Websocket来实现实时消息传递。在这种情况下，Websocket的持久连接可以在服务器上保持打开状态，以便客户端可以接收实时消息。这种实时通信的能力使得Websocket在许多应用程序中得到了广泛的应用。

总之，Websocket技术在现代Web应用程序中发挥着越来越重要的作用。它可以减少网络延迟和服务器负载，处理大量的并发连接，并提供实时通信能力。因此，如果您正在构建一个需要实时更新的Web应用程序，那么Websocket技术可能是您的理想选择。

封装类实现

import { WebSocketConfigOption } from './WebSocketConfigOption';

export class ReconnectableWebSocket {

   private ws!: WebSocket; // ws实例
   private opt: WebSocketConfigOption; // ws配置项
   private lockReconnect: boolean = false; // 避免ws重复连接
   private isClosingWindow: boolean = false;
   private reconnectTimeout: any;
   private heartSendInterval: any;

   constructor(option: WebSocketConfigOption) {
      if (null === option.url || '' === option.url) {
         throw ('url不能为空');
      }
      this.opt = option;
      this.initWebSocket();
   }

   private initWebSocket() {
      if (null == this.opt.secWebSocketProtocol) {
         this.ws = new WebSocket(this.opt.url);
      } else if (this.opt.secWebSocketProtocol.length == 0) {
         this.ws = new WebSocket(this.opt.url);
      } else {
         this.ws = new WebSocket(this.opt.url, this.opt.secWebSocketProtocol);
      }
      this.initEventHandle();
      window.onbeforeunload = () => {
         this.isClosingWindow = true;
         this.ws.close(); // 当窗口关闭时，主动去关闭websocket连接。
      }
   }

   private initEventHandle() {
      this.ws.onclose = () => {
         console.log('ws连接关闭!' + this.opt.url);
         this.opt.onclose && this.opt.onclose();
         this.heartCheckStop();
         if (!this.isClosingWindow) {
            this.reconnect();
         }
      }
      this.ws.onerror = () => {
         console.log('ws连接错误!' + this.opt.url);
         this.opt.onerror && this.opt.onerror();
         this.heartCheckStop();
         if (!this.isClosingWindow) {
            this.reconnect();
         }
      }
      this.ws.onopen = () => {
         console.log('ws连接成功!' + this.opt.url);
         this.opt.onopen && this.opt.onopen();
         this.heartCheckStart();
      }
      this.ws.onmessage = (event: any) => {
         this.opt.onmessage && this.opt.onmessage(event);
      }
   }

   /** 重连 */
   private reconnect() {
      if (this.lockReconnect) {
         return;
      }
      this.lockReconnect = true;
      this.reconnectTimeout = setTimeout(() => {
         this.initWebSocket();
         this.lockReconnect = false;
      }, 2000);
   }

   /** 关闭重连 */
   private reconnectStop(): void {
      clearTimeout(this.reconnectTimeout);
   }

   /** 开启心跳包保持连接 */
   private heartCheckStart(): void {
      this.ws.send('heartCheck');
      this.heartSendInterval = setInterval(() => {
         this.ws.send('heartCheck');
      }, 5 * 60 * 1000);
   }

   /** 关闭心跳包 */
   private heartCheckStop(): void {
      clearInterval(this.heartSendInterval);
   }

   /** 主动关闭连接 */
   public close(): void {
      this.reconnectStop();
      this.heartCheckStop();
      this.isClosingWindow = true;
      this.ws.close();
   }

}

配置类实现

export type WebSocketConfigOption = {

   url: string;
   secWebSocketProtocol?: Array<string>;
   onopen?: () => void;
   onmessage?: (msg: any) => void;
   onerror?: () => void;
   onclose?: () => void;

}

应用示例

import { WebSocketConfigOption } from '../websocket/WebSocketConfigOption';
import { ReconnectableWebSocket } from '../websocket/ReconnectableWebSocket';
import { InnerMqService } from '../../rx/inner-mq.service';

export class MapMessageConnection {

   private ws!: ReconnectableWebSocket;

   constructor(
      private path: string,
      private innerMqService: InnerMqService,
   ) {
      this.connection();
   }

   /** 连接 */
   private connection(): void {
      let wsConfig: WebSocketConfigOption = {
         url: this.path,
         onopen: () => {
         },
         onerror: () => {
         },
         onmessage: (msg: any) => {
            if (msg.data && msg.data !== '') {
               let data = JSON.parse(msg.data);
               this.innerMqService.pub(data.title, data.content);
            }
         }
      }
      this.ws = new ReconnectableWebSocket(wsConfig);
   }

   /** 断开连接 */
   public disConnection(): void {
      this.ws.close();
   }

}

import { InnerMqClient } from '../../rx/inner-mq.service';
import { SubmitService } from '../../service/submit.service';
import { MapBase } from '../../map/map-base';
import { CommonUtil } from '../../util/common-util';
import { MapPage } from '../../view/page/map/map.page';
import { MapDraw } from '../../map/draw/map-draw';
import { MapWrap } from '../../map/draw/map-wrap';
import { GeoUtil } from "../../map/geo-util";
import { Point } from "../../map/entity/Point";

export class MapMessageProcessor {

   constructor(
      private mqClient: InnerMqClient,
      private submitService: SubmitService,
      private mapBase: MapBase,
      private mapPage: MapPage,
   ) {
      /** 放大 */
      mqClient.sub('ZoomIn').subscribe((res) => {
         mapBase.zoomIn();
      });
      /** 缩小 */
      mqClient.sub('ZoomOut').subscribe((res) => {
         mapBase.zoomOut();
      });
      /** 拖动 */
      mqClient.sub('Pan').subscribe((res) => {
         mapBase.pan();
      });
      /** 显示网格 */
      mqClient.sub('GridSwitch').subscribe((res) => {
         let update;
         if (mapBase.getGridVisible()) {
            mapBase.closeGrid();
            update = false;
         } else {
            mapBase.showGrid();
            update = true;
         }
         let config = mapBase.getMapConfig();
         if (config) {
            config.grid = update;
            CommonUtil.setConfigCache(config);
            mapBase.setMapConfig(config);
         }
      });
      /** 切换图层源 */
      mqClient.sub('SwitchResource').subscribe((res) => {
         // 切换图层
         debugger
         let lastType = mapBase.getCurrentCoordinateType();
         mapBase.switchMapResource(res);
         let currentType = mapBase.getCurrentCoordinateType();
         // 保存设置
         let config = mapBase.getMapConfig();
         if (config) {
            config.layer = res;
            CommonUtil.setConfigCache(config);
            mapBase.setMapConfig(config);
         }
         // 检查坐标类型
         if (lastType != currentType) {
            if (lastType == 'wgs84' && currentType == 'gcj02') {
               mapBase.turnMapFeaturesFromWgs84ToGcj02();
            } else if (lastType == 'gcj02' && currentType == 'wgs84') {
               mapBase.turnMapFeaturesFromGcj02ToWgs84();
            }
         }
         // 回调
         setTimeout(() => {
            mapPage.updateShowInfo();
         });
      });
      /** 绘制类型切换 - */
      mqClient.sub('SwitchDrawType').subscribe((res) => {
         mapBase.setDrawType(res);
      });
      /** 绘制 - */
      mqClient.sub('OpenDraw').subscribe((res) => {
         mapBase.pan();
         mapBase.removeDrawedFeatures();
         mapBase.openDraw({
            drawEnd: () => {
               setTimeout(() => {
                  mapBase.removeDrawInteraction();
               })
            },
            modifyEnd: () => {
            }
         });
      });
      /** 绘制指定多边形并定位 - */
      mqClient.sub('DrawPolygonAndPositioning').subscribe((res) => {
         mapBase.pan();
         mapBase.removeDrawedFeatures();
         let blocks = JSON.parse(res);
         for (let i = 0; i < blocks.length; i++) {
            let points: Array<Point> = [];
            for (let j = 0; j < blocks[i].length; j++) {
               let point = new Point(blocks[i][j].lng, blocks[i][j].lat);
               if (mapBase.getCurrentCoordinateType() == 'wgs84') {
                  points.push(GeoUtil.gcj02_To_wgs84(point));
               } else {
                  points.push(point);
               }
            }
            let feature = MapDraw.createPolygonFeature(points);
            MapWrap.addFeature(mapBase, mapBase.drawLayerName, feature);
         }
         mapBase.setFitviewFromDrawLayer();
      });
      /** fitview - */
      mqClient.sub('Fitview').subscribe((res) => {
         mapBase.setFitviewFromDrawLayer();
      });
      /** 删除绘制 - */
      mqClient.sub('RemoveDrawedShape').subscribe((res) => {
         mapBase.removeDrawedFeatures();
      });
      /** 提交区块下载 - */
      mqClient.sub('SubmitBlockDownload').subscribe((res) => {
         let data = {
            tileName: this.mapBase?.getCurrentXyzName(),
            mapType: CommonUtil.getMapType(this.mapBase?.getCurrentXyzName()),
            tileUrl: this.mapBase?.getCurrentXyzUrlResources(),
            points: this.mapBase?.getDrawedPoints(),
         };
         this.submitService.blockDownload(data).then((r) => {
         });
      });
      /** 提交世界下载 - */
      mqClient.sub('SubmitWorldDownload').subscribe((res) => {
         let data = {
            tileName: this.mapBase?.getCurrentXyzName(),
            mapType: CommonUtil.getMapType(this.mapBase?.getCurrentXyzName()),
            tileUrl: this.mapBase?.getCurrentXyzUrlResources()
         };
         this.submitService.worldDownload(data).then((r) => {
         });
      });
   }

}

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