我想在 flask 里返回 pandas 生成的 Excel 表格, 但又不想保存这个文件 有没有办法,跳过生成文件这个步骤? 我想到用流处理,但不知道该怎么弄 - V2EX
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aieike

我想在 flask 里返回 pandas 生成的 Excel 表格, 但又不想保存这个文件 有没有办法,跳过生成文件这个步骤? 我想到用流处理,但不知道该怎么弄

  •  
  •   aieike
    AIEIKE Aug 19, 2019 3824 views
    This topic created in 2453 days ago, the information mentioned may be changed or developed.

    这是代码

    def download_excel(): try: logger.info('download_excel, %s' % str(request.form)) form_data = json.loads(request.form.get('data')) header_names = form_data['header_names'] headers = form_data['headers'] rows = form_data['list'] data = OrderedDefault(list) for row in rows: for i, header_name in enumerate(header_names): header = headers[i] data[header_name].append(row[header]) file_name = 'temp_data/temp.xlsx' pd.DataFrame(data).to_excel(file_name, index=False) respOnse= make_response(send_file(file_name)) return response except Exception as e: logger.exception(e) return make_response('Error', 301) 
    Supplement 1    Aug 20, 2019

    修改完后代码

    def download_excel(): try: logger.info('download_excel, %s' % str(request.form)) form_data = json.loads(request.form.get('data')) header_names = form_data['header_names'] headers = form_data['headers'] rows = form_data['list'] data = OrderedDefault(list) for row in rows: for i, header_name in enumerate(header_names): header = headers[i] data[header_name].append(row[header]) bf = io.BytesIO() pd.DataFrame(data).to_excel(bf, index=False) logger.info('Excel file size: {}'.format(bf.tell())) bf.seek(0) return send_file(bf, mimetype='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet') except Exception as e: logger.exception(e) return make_response('Error', 301) 
    16 replies    2019-08-27 20:04:29 +08:00
    Nostalgiaaaa
        1
    Nostalgiaaaa  
       Aug 19, 2019
    试试 StringIO ?
    aieike
        2
    aieike  
    OP
       Aug 19, 2019
    @Nostalgiaaaa 我试了,但没成功,可能我的方法不对
    vZexc0m
        3
    vZexc0m  
       Aug 19, 2019
    julyclyde
        5
    julyclyde  
       Aug 19, 2019
    @aieike “没成功”三个字没什么信息量
    你需要写的是“但是遇到了叉叉错误”
    aieike
        6
    aieike  
    OP
       Aug 19, 2019
    @vZexc0m 谢谢, 用这句解决了
    respOnse= send_file(buffer,
    attachment_filename=filename,
    as_attachment=True)
    wuwukai007
        7
    wuwukai007  
       Aug 19, 2019 via Android
    有个问题,这个 io 是放在内存当中,如何放入 redis 中呢,或者集成到类似 django 的 cache 中
    janxin
        8
    janxin  
       Aug 19, 2019
    @wuwukai007 这个 io 是 file-like,支持读写操作
    wuwukai007
        9
    wuwukai007  
       Aug 19, 2019 via Android
    @ janxin 我的意思是,如果用户量大的话,这个 io 是用的本地的内存,怎么用 redis 之类作为 io 的存储
    reself
        10
    reself  
       Aug 19, 2019 via Android
    用 BytesIO 试试看,pandas 有个 ExcelWriter 组件,可以往 filelike 的对象里写东西。对了,io 对象写好过后记得要 seek(0)。
    1462326016
        11
    1462326016  
       Aug 20, 2019
    一楼的意思应该是 BytesIO ?
    ebingtel
        12
    ebingtel  
       Aug 20, 2019
    @wuwukai007 既然是 file-like,可以 read 出来,存进 redis 的吧?但是存个 excel 的 io 好,还是存原始的数据,这个还需要权衡下
    aieike
        13
    aieike  
    OP
       Aug 20, 2019
    @reself 对的, 我当时没有 seek(0), 也没加 minetype, 所以报错了
    aieike
        14
    aieike  
    OP
       Aug 20, 2019
    还有一个问题,想问一下, 这个 Bytesio 需不需要像文件那样 close
    LUXiaobo
        15
    LUXiaobo  
       Aug 21, 2019
    试试 tempfile
    aieike
        16
    aieike  
    OP
       Aug 27, 2019
    @LUXiaobo 是个不错的方法[赞]
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