nodejs koa框架下载和导入excel

const service = require("../service/model.service");
const urlencode = require("urlencode");
const helper = require("../../utils/helper");
module.exports = {
   /**
 * @description: 下载导入度量模板
 * @param {type} 
 * @return: 
 */
   "GET /model/metricsDown": async (ctx, bean) => {
      let excel = await service.metricsDown(bean);
      if (!excel) {
         throw new Error("下载失败");
      }
      let name = urlencode(excel.sheetName + '.xlsx', "utf-8");
      ctx.response.set(
         "Content-Disposition",
         "attachment; " + helper.setDownLoadFilename(ctx.req.headers["user-agent"], name)
      );
      ctx.response.body = excel.buffer; // 返回在响应体里
   },
   /**
   * @description: 导入度量
   * @param {type} 
   * @return: 
   */
   "POST /model/metricsImport": async (ctx, bean) => {
      const file = ctx.request.files.file; // 获取上传文件
      let result = await service.metricsImport(file, bean);
      return result
   },
}

const dao = require("../dao/model.dao");
const mysql = require("mysql");
const h = require("../../utils/helper");
const { v4: uuidv4 } = require('uuid');
const xlsx = require("node-xlsx");
const path = require('path');
const fs = require('fs');
module.exports = {
   /**
  * @description: 下载导入度量模板
  * @param {*} need
  * @return {*}
  */
   async metricsDown() {
      var data = [['度量名称', '度量英文名', '度量SQL'], ['必填项', '必填项', '必填项']];
      const sheetName = '导入度量模板';
      var buffer = xlsx.build([{ name: sheetName + ".xlsx", data: data }]);
      return {
         sheetName,
         buffer,
      };
   },
   /**
 * @description: 导入度量
 * @param {*} need
 * @return {*}
 */
   async metricsImport(file, params) {
      // 创建可读流
      if (!params.fileName || !params.code) throw new Error("参数不合法！！！");

      const reader = fs.createReadStream(file.path);
      if (!params.fileName.endsWith('xls') && !params.fileName.endsWith('xlsx')) {
         throw new Error('请上传xls或xlsx格式的文件');
      }
      let filePath = path.join(__dirname, "../../../download/") + `${file.name}`;
      // 创建可写流
      const upStream = fs.createWriteStream(filePath);
      // 可读流通过管道写入可写流
      reader.pipe(upStream);
      return filePath
   },
}