axios下载文件.net Core

参考：

axios 下载文件 - 简书 (jianshu.com)

1.第一步，优化ajax.js

getDownLoad(pageContext, url, param) {
    var config = axiosProvider.getconfig(pageContext)
    config.params = param
    var req = _ajaxRemote.post(
      url,
      Object.assign({ responseType: 'blob' }, config)
    )
    return this.downloadBase(req)
  },
  postDownLoad(pageContext, url, data, param) {
    var config = axiosProvider.getconfig(pageContext)
    config.params = param
    var req = _ajaxRemote.post(
      url,
      data,
      Object.assign({ responseType: 'blob' }, config)
    )
    return this.downloadBase(req)
  },
  downloadBase(req) {
    return new Promise((resolve, reject) => {
      req
        .then((res) => {
          console.log('req.THEN')
          if (!res) {
            this.$message.error('下载模板文件失败')
            return false
          }
          const blob = new Blob([res.result], {
            type:
              'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8',
          })
          const downloadElement = document.createElement('a')
          const href = window.URL.createObjectURL(blob)
          //从response的headers中获取filename, 后端response.setHeader("Content-disposition", "attachment; filename=xxxx.docx") 设置的文件名;
          let contentDisposition = res.headers['content-disposition']
          let patt = new RegExp('filename=([^;]+\.[^\.;]+);*')
          let result = patt.exec(contentDisposition)
          let filename = decodeURI(result[1])
          // let filename = '模块配置.json';
          downloadElement.style.display = 'none'
          downloadElement.href = href
          downloadElement.download = filename //下载后文件名
          document.body.appendChild(downloadElement)
          downloadElement.click() //点击下载
          document.body.removeChild(downloadElement) //下载完成移除元素
          window.URL.revokeObjectURL(href) //释放掉blob对象
          resolve()
        })
        .catch(() => {
          reject()
        })
    })
  },

2.第二部，后台实现

 　　

　　 注意ms.position=0这句话要有，不然返回会报错

　　如果不添加Access-Control-Expose-Headers的话，Content-Disposition前台会无法获取

 　　也可以直接使用byte[]来返回　　

　　

 　　代码:

　　

 public async Task<IActionResult> export(List<string> rowIDs)
 {
 　　　　　　 var str = Newtonsoft.Json.JsonConvert.SerializeObject(data);
            byte[] bytes = Encoding.UTF8.GetBytes(str);
            
            //new Microsoft.AspNetCore.StaticFiles.FileExtensionContentTypeProvider().Mappings.TryGetValue(".json", out var contenttype);
            System.Net.Mime.ContentDisposition cd = new System.Net.Mime.ContentDisposition()
            {
                FileName = HttpUtility.UrlEncode("模块配置.json"),
                Inline = false
            };

            Response.Headers.Add("Access-Control-Expose-Headers", "Content-Disposition");
            Response.Headers.Add("Content-Disposition", cd.ToString());

            var v = File(bytes, "application/octet-stream");
            return v;
}

　3. 前台实现

由于axios进行了封装，重构了res.data

所以这里Blob的时候有所出入 

      ajax.postDownLoad(this, "/Module/export", rows)
        .then(() => {
          component.loading = false;
        })

注意如果后台没有在Header中添加Access-Control-Expose-Headers的话，这里res.headers['content-disposition']会无法获取