Koa/Node环境下，实现前后端文件创建和文件下载

后端代码示例：

const datasrc = await project.dataSource('info_platform_database');
const {
  knex
} = datasrc;
const db = 'info_platform';
const name = 'export_data';
const table = `${db}.${name}`;
// 导入文件处理需要的工具
const { Blob, Buffer } = require('node:buffer');

const {
  ctx
} = this;

const urlPre = 'https://example.com/';
const params = ctx.request.body;

const sql = `
  select
    info_platform.content.source_id as source_id 
  from
  	info_platform.content
  where info_platform.content.source_id >= ${params.minId} and info_platform.content.source_id <= ${params.maxId}
  order by
    info_platform.content.source_id asc`
let [data] = await knex.raw(sql)
data = data.map(item => urlPre+item.source_id) // 假设文件内容是URL拼接

// 先通过Blob构造文件内的数据，再获取其arrayBuffer数据
const blob = await (new Blob([data.join('\n')], { type: 'text/plain', endings: 'native' })).arrayBuffer();
// 通过Buffer.from将arrayBuffer转换成Buffer，只有Buffer类型才能被顺利传输过去下载
ctx.body = Buffer.from(blob);

前端代码示例：

async (row) => {
  const { data } = await axios.post(`https://.../exportUrlFile`, { //调用后端对应接口
    minId: row.min_id,
    maxId: row.max_id,
  }, {
    responseType: 'arraybuffer', // 此处需要设置为arraybuffer
  });

  function download(blob, fileName) {
    const url = blobToUrl(blob);
    const link = document.createElement('a');
    link.style.display = 'none';
    link.href = new URL(url);
    link.setAttribute('download', fileName);
    document.body.appendChild(link);
    link.click();
  };

  function blobToUrl(blob) {
    try {
      const file = new Blob([blob])
      console.log(file);
      let url = null;
      if (window.createObjectURL !== undefined) {
        console.log("createObjectURL");
        url = window.createObjectURL(file);
      } else if (window.webkitURL !== undefined) {
        console.log("webkitURL");
        console.log(window.webkitURL)
        url = window.webkitURL.createObjectURL(file);
        console.log(file);
      } else if (window.URL !== undefined) {
        console.log("URL");
        url = window.URL.createObjectURL(file)
      }
      return url;
    } catch (e) {
      console.log(e)
      alert('系统出错')
    }
  };
  download(data, 'URL链接.txt')
}

参考文章：juejin.cn/post/718766…