需求：加載驗證碼；1.下載驗證碼圖像文件；2.獲取header里面驗證碼ID

踩坑--踩坑--踩坑

根據文檔使用 request.downloadFile 請求，官方示例:

// pages/xxx.ets
// 將網絡資源文件下載到應用文件目錄并讀取一段內容
import common from '@ohos.app.ability.common';
import fs from '@ohos.file.fs';
import request from '@ohos.request';

// 獲取應用文件路徑
let context = getContext(this) as common.UIAbilityContext;
let filesDir = context.filesDir;

try {
  request.downloadFile(context, {
    url: 'https://xxxx/xxxx.txt',
    filePath: filesDir + '/xxxx.txt'
  }).then((downloadTask) = > {
    downloadTask.on('complete', () = > {
      console.info('download complete');
      let file = fs.openSync(filesDir + '/xxxx.txt', fs.OpenMode.READ_WRITE);
      let buf = new ArrayBuffer(1024);
      let readLen = fs.readSync(file.fd, buf);
      console.info(`The content of file: ${String.fromCharCode.apply(null, new Uint8Array(buf.slice(0, readLen)))}`);
      fs.closeSync(file);
    })
  }).catch((err) = > {
    console.error(`Invoke downloadTask failed, code is ${err.code}, message is ${err.message}`);
  });
} catch (err) {
  console.error(`Invoke downloadFile failed, code is ${err.code}, message is ${err.message}`);
}復制

里面存在一個解決不到的問題是，獲取不到header里面驗證碼ID，downloadTask 無法獲取....只能換常規方法獲取了。

換 httpRequest.request 來請求，示例代碼如下：

/**
   * 下載文件(驗證碼使用)
   */
  static httpFileDownload(url: string, params?: any): Promise< ResponseResultJson > {
    LogUtils.i("下載文件URL：" + url + "n請求參數:" + (params != undefined ? "n請求參數:" + JSON.stringify(params) : "無參數"));
    //
    let httpRequest = http.createHttp();
    httpRequest.on('headersReceive', (header) = > {
      //用于訂閱HTTP響應頭，此接口會比request請求先返回。可以根據業務需要訂閱此消息
    });
    //
    let responseResult = httpRequest.request(url, {
      method: http.RequestMethod.GET,
      readTimeout: RequestConstants.readTimeout,
      connectTimeout: RequestConstants.connectTimeout,
      header: {
        'Content-Type': ContentType.JSON
      },
      expectDataType: http.HttpDataType.ARRAY_BUFFER, // 可選，指定返回數據的類型
      extraData: params
    });
    let responseResultJson = new ResponseResultJson();
    return responseResult.then(async (responseResult: http.HttpResponse) = > {
      LogUtils.i("文件下載請求響應URL：" + url + "n響應結果:" + "n" + JSON.stringify(responseResult));
      if (responseResult.responseCode === ResponseConstants.RESPONSE_SUCCESS) {
        let header = responseResult.header
        LogUtils.i('解析響應 header n' + JSON.stringify(header));
        let headerJson = JSON.stringify(header)
        let headerObj = JSON.parse(headerJson)
        let sessionId = headerObj.sessionid as string
        let serverModel = headerObj.servermodel as string
        let encryptType = headerObj.encrypttype as string
        //保存 header
        await AppHelper.commitSessionId(sessionId);
        await AppHelper.commitServerModel(serverModel);
        await AppHelper.commitEncryptType(encryptType);
        //解析文件
        let result = responseResult.result as ArrayBuffer
        // let filePath = FileConstants.rootFile + "/verifyCode_" + TimeExUtils.getNowYMDHMS1() + '.jpg'
        let isHave = fs.accessSync(FileConstants.pathFile) //檢查文件目錄是否存在
        if (!isHave) fs.mkdirSync(FileConstants.pathFile) //創建目錄
        //
        let filePath = FileConstants.pathFile + "verifyCode_" + TimeExUtils.getNowYMDHMS1() + '.jpg'
        let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
        fs.writeSync(file.fd, result); //將數據寫入文件
        fs.closeSync(file); //關閉文件
        //
        LogUtils.i("保存文件成功:n" + filePath + "t" + await FileUtils.getPathSize(filePath));
        //結果
        responseResultJson.code = ResponseConstants.CODE_SUCCESS
        responseResultJson.isSuccess = true
        responseResultJson.status = responseResult.responseCode
        responseResultJson.serverModel = serverModel
        responseResultJson.filePath = filePath
      } else {
        responseResultJson.code = ResponseConstants.CODE_ERROR;
        responseResultJson.message = "業務異常:" + JSON.stringify(responseResult)
        responseResultJson.isSuccess = false
      }
      return responseResultJson;
    }).catch((error) = > {
      LogUtils.i("文件下載請求響應URL：" + url + "n請求異常:n" + JSON.stringify(error))
      responseResultJson.code = ResponseConstants.CODE_ERROR;
      responseResultJson.message = "請求異常:n" + JSON.stringify(error)
      responseResultJson.isSuccess = false
      return responseResultJson;
    });
  }復制

里面無用工具類可以不用在意...里面獲取header可以有2種方法

方法一：

資料拿取+mau123789是v喔
 httpRequest.on('headersReceive', (header) = > {
      //用于訂閱HTTP響應頭，此接口會比request請求先返回?？梢愿鶕I務需要訂閱此消息
    });

方法二：

let header = responseResult.header
        LogUtils.i('解析響應 header n' + JSON.stringify(header));
        let headerJson = JSON.stringify(header)
        let headerObj = JSON.parse(headerJson)
        let sessionId = headerObj.sessionid as string
        let serverModel = headerObj.servermodel as string
        let encryptType = headerObj.encrypttype as string

獲取的值是一樣的。

獲取驗證碼文件關鍵代碼：

1.參數里面的 expectDataType 需要設置為 http.HttpDataType.ARRAY_BUFFER；

2. 結果轉換為ArrayBuffer，let result = responseResult.result as ArrayBuffer

運行日志：

運行效果：

完畢啦?。。?！ 驗證碼獲取成功了?。。?！

審核編輯 黃宇