【Angular2】基于localStorage实现本地备份操作记录

引言

项目中需要对用户的操作记录备份起来，如果后端出现任何问题，可以从前端把用户操作记录提取出来，然后后期把数据导入到数据库

功能

1.监测每条记录的提交情况，分辨出是客户端和服务器问题；
2.呼吸灯动态显示当前整体提交状况；
3.监控中心可以查看每条记录的提交情况；
4.监控中心可以控制对每条记录的监控状态；
5.监控中心可以切换对操作记录的备份模式；

设计思路

1.首先各个题型组件在调取服务之后，通过服务返回的值来判断提交情况，并记录操作，如果有问题则为服务端故障，同时更新网络状态；

2.如果调取服务出现任何异常导致无法获取返回值，则为客户端问题，记录操作并标记，同时更新网络状态；

3.呼吸灯实时监测网络状态，累计3次故障后客户端报警；

4..进入监控中心，读取所有操作记录及其标记，显示提交情况，同时根据具体情况选择性的关闭对应的记录的监测（否则会一直报警）；

5.监控中心如果出现很多问题或者关键性问题，可以开启备份操作下载功能，用户操作完成之后会把操作自动下载到本地；

代码说明

各题目组件 ts

/* 向后台提交学生答案 */
  public updateStudentAnswerToBackend(answer: Answer) {
    let url: string = "examinationEvaluation-web/onlineExam/updatePaperRecordByRecord" + this.authGuardService.getTicket();
    let body: string = JSON.stringify(answer);
    this.exampapaerservice.post(url,body).subscribe(
      res => {
        if (res.json().code == "1111" || res.json().data != true) {
          this.backupAnswer(answer,1); //备份答案
        } else {
          this.backupAnswer(answer,0); //备份答案
        }
      }
    );
    console.log("学生提交答案-radio");
  }

  /* 备份用户答案 */
  private backupAnswer(answer: Answer,status: number) {
    //备份答案记录
    console.log("answer-backup-log---"+ExamPaperService.userOperationAmount);
    ExamPaperService.userOperationAmount++; //操作序号递增
    localStorage.setItem("userOperationAmount",ExamPaperService.userOperationAmount.toString()); //记录操作序号
    localStorage.setItem(answer.studentId + ExamPaperService.userOperationAmount,JSON.stringify(answer) + status); //记录操作内容
    //记录提交情况
    let flag: boolean = true;
    let ns: string[] = JSON.parse(localStorage.getItem("NetWorkState"));
    for (var i = 0; i < ns.length; i++) {
      if (answer.questionMainId == ns[i]) { flag = false; }
    }
    if (status != 0 && flag) {
      ns[0] = (parseInt(ns[0]) + 1).toString();
      localStorage.setItem("NetWorkState",JSON.stringify(ns));
    }
  }

公共服务 ts

/* 处理失败提交 */
  public handleUpdateAnswerError(error: Response) {
    //保存用户答案到localStorage
    let answer: Answer = <Answer>(JSON.parse(ExamPaperService.studentAnswer));
    this.backupAnswer(answer,2);
    return Observable.throw(error.json().error || '网络问题：server error');
  }

  /* 备份用户答案 */
  private backupAnswer(answer: Answer,status: number) {
    //备份答案记录
    console.log("answer-backup-log---" + ExamPaperService.userOperationAmount);
    ExamPaperService.userOperationAmount++; //操作序号递增
    localStorage.setItem("userOperationAmount",JSON.stringify(ns));
    }
  }

监控中心 ts

ngOnInit() {
    //获得当前操作数量
    this.getUserOperationAmount();
    //初始化网络状态
    let networkList: string[] = [];
    networkList.push("0");
    localStorage.setItem("NetWorkState",JSON.stringify(networkList));
    //初始化备份模式
    localStorage.setItem("NetWorkBackupPattern","0");
    //开始监测
    this.startMonitorNetworkStatus();
  }

  /* 开始监测网络状态 */
  startMonitorNetworkStatus() {
    this.timer = setInterval(() => { this.networkState = parseInt(JSON.parse(localStorage.getItem("NetWorkState"))[0]); let el: Element = document.getElementById("networkstate"); if (this.networkState == 1) { el.setAttribute("class","breathe-yellow-btn"); } else if (this.networkState == 3) { el.setAttribute("class","breathe-red-btn"); } else if (this.networkState > 3) { this.display_error = true; let ns: string[] = JSON.parse(localStorage.getItem("NetWorkState")); ns[0] = "3"; localStorage.setItem("NetWorkState",JSON.stringify(ns)); } },1000); } /* 刷新状态 */ refreshStatus() { this.getAnswerStatus(); this.getMonitorStatus(); } /* 清除缓存 */ clearLocalStorage() { localStorage.clear(); } /* 获得题目提交状态 */ getAnswerStatus() { console.log("Start-getAnswerStatus-------"); for (var i = 0; i < parseInt(localStorage.getItem("userOperationAmount")); i++) { let answerLog: string = localStorage.getItem(localStorage.getItem("userId") + i); let answerStatus = answerLog.substring(answerLog.length - 1); let answer: Answer = JSON.parse(answerLog.substring(0,answerLog.length - 1)); if (answerStatus == "0") { let el = document.getElementById("network" + answer.questionMainId); if (el != null) { el.setAttribute("class","badge badge-success badge_postion"); el.innerHTML = "成功提交"; } } if (answerStatus == "1") { let el = document.getElementById("network" + answer.questionMainId); if (el != null) { el.setAttribute("class","badge badge-warning badge_postion"); el.innerHTML = "客户端故障"; } } if (answerStatus == "2") { let el = document.getElementById("network" + answer.questionMainId); if (el != null) { el.setAttribute("class","badge badge-important badge_postion"); el.innerHTML = "服务器故障"; } } } } /* 获得检测状态 */ getMonitorStatus() { console.log("Start-getMonitorStatus-------"); let idList: string[] = JSON.parse(localStorage.getItem("NetWorkState")); for (var i = 1; i < idList.length; i++) { let el = document.getElementById("monitor" + idList[i]); if (el != null) { el.setAttribute("class","btn btn-danger btn-xs pull-right"); el.innerHTML = "监测已停止"; } } } /* 获得操作记录数量 */ getUserOperationAmount() { let amount: number = 1; while (localStorage.getItem("userId" + amount)!=null) { amount++; } localStorage.setItem("userOperationAmount",(amount-1).toString()); } /* 切换监测状态 */ changeMonitorStatus(monitorId: string) { console.log("Start-changeMonitorStatus-------"); let exitFlag: boolean = true; let questionId = monitorId.substring(7,monitorId.length); let idList: string[] = JSON.parse(localStorage.getItem("NetWorkState")); for (var i = 0; i < idList.length; i++) { if (questionId == idList[i]) { //切换为开始 let el = document.getElementById("monitor" + idList[i]); if (el != null) { el.setAttribute("class","btn btn-primary btn-xs pull-right"); el.innerHTML = "正在监测中"; } idList.splice(i,1); localStorage.setItem("NetWorkState",JSON.stringify(idList)); exitFlag = false; } } //切换为停止 if (exitFlag) { let el = document.getElementById(monitorId); if (el != null) { el.setAttribute("class","btn btn-danger btn-xs pull-right"); el.innerHTML = "监测已停止"; } idList.push(questionId); localStorage.setItem("NetWorkState",JSON.stringify(idList)); } } private backupPatternStatus: boolean = false; //备份模式状态 /* 切换备份模式 */ changeBackupPattern() { if (this.backupPatternStatus) { //切换为不备份 let el = document.getElementById("networkbackuppattern"); if (el != null) { el.setAttribute("class","btn btn-info pull-left"); el.innerHTML = "非备份模式"; localStorage.setItem("NetWorkBackupPattern","0"); this.backupPatternStatus = false; } } else { //切换为开始备份 let el = document.getElementById("networkbackuppattern"); if (el != null) { el.setAttribute("class","btn btn-warning pull-left"); el.innerHTML = "备份模式中"; localStorage.setItem("NetWorkBackupPattern","1"); this.backupPatternStatus = true; } } } /* --------------------------------------------------------- */ private openNum: number = 0;//点击三次可以打开 /* 打开模态框 */ openModal(modal: HTMLElement) { this.openNum++; if (this.openNum > 2) { this.refreshStatus(); modal.style.visibility = 'visible'; this.openNum = 0; } } /* 关闭模态框 */ close(modal: HTMLElement) { modal.style.visibility = 'hidden'; } /* 拖动模态框 */ draggable() { $('.modal-dialog').draggable(); } 

本地备份下载 ts

/* 创建备份文本并下载 */
  createBackupText() {
    let userLog: string = "";
    for (var i = 0; i < parseInt(localStorage.getItem("userOperationAmount")); i++){
      userLog = userLog +localStorage.getItem(localStorage.getItem("userId")+i);
    }
    let data = new Blob([userLog],{ type: 'application/json' })
    var link = document.createElement("a");
    link.setAttribute("href",window.URL.createObjectURL(data));
    link.setAttribute("download",localStorage.getItem("userId") + '.json');
    link.style.visibility = 'hidden';
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    console.log("------ Start Create File And Download --------");

  }

小结

要针对不同的业务场景采取不同的解决方案，尽可能考虑全面