定時獲取伺服器時間戳的一個類（Typescript）
阿新 • • 發佈：2019-05-23
export class TimeStampService {
private _local_timestamp: number; // 本地時間戳
private _server_timestamp: number; // 伺服器端時間戳
private _duration: number = 1000 * 60 * 5; // 時間戳更新頻率 （毫秒)
private _timeDiffer: number; // 伺服器和本地的時間差 伺服器-本地
constructor(
) {
this._timeDiffer = 0;
this.getTimeDiffer();
}
private getTimeDiffer() {
const xhr = new XMLHttpRequest();
xhr.open('get', environment.URL_TIME, true);
const that = this;
xhr.onload = function () {
if (this.status === 200) {
const result = JSON.parse(this.response);
const now = new Date().getTime();
that._timeDiffer = result.data.timestamp - now;
}
};
xhr.onerror = function () {
console.log('xhr error', xhr);
};
xhr.send();
}
get Duration() {
return this._duration;
}
get ServerTimeStamp() {
if (!this._local_timestamp) {
this._local_timestamp = new Date().getTime();
} else {
const now = new Date().getTime();
// 提前30秒做一次非同步矯正
if (now - this._local_timestamp > this.Duration - 1000 * 30) {
this.getTimeDiffer(); // 更新差值 防止使用者修改本地時間
}
if (now - this._local_timestamp > this.Duration) {
this._local_timestamp = now;
}
}
this._server_timestamp = this._local_timestamp + this._timeDiffer;
return this._server_timestamp;
}
}