node express buffer excel传输到前端下载

深碍√TFBOYSˉ_ 2022-01-19 05:51 258阅读 0赞

## 因为要使用js-xlsx获取json转为xlsx，传输给前端下载。翻了很多的文档，js-xlsx的文档真的难读啊。 ##

*  "xlsx": "^0.14.1"
 *  这个issue能有点帮助 [github.com/SheetJS/js-…][github.com_SheetJS_js-]
 *  这里面有res.download的实现过程 [github.com/expressjs/e…][github.com_expressjs_e]

## 方式1 ##

*  buffer 直接通过stream 传输给前端。好处就是不用先存再download了

const XLSX = require('xlsx');
    var stream = require('stream');
        const book = XLSX.utils.book_new();
        const sheet = XLSX.utils.aoa_to_sheet([
            ["你好", "我不好", "嘻嘻嘻"],
            [1, 2, 3],
            [3, 4, 5],
            [8, 7, 6],
            [213, 123, 123],
        ]);
        XLSX.utils.book_append_sheet(book, sheet, "test");
    
        const fileContents = XLSX.write(book, { type: 'buffer', bookType: 'xlsx', bookSST: false });
        
        var readStream = new stream.PassThrough();
        readStream.end(fileContents);
    
        let fileName = "text.xlsx";
        res.set('Content-disposition', 'attachment; filename=' + fileName);
        res.set('Content-Type', 'text/plain');
    
        readStream.pipe(res);
    复制代码

## 方式2 ##

*  可以在服务器保存一份。

// fileContents 是上面的fileContents，一样的buffer。
        let fileName = moment().format('YYYYMMDDHHmmss') + '.xlsx';
        let filePath = 'doc/' + fileName;
        fs.writeFileSync(filePath, fileContents, { encoding: 'binary' });
        return res.download(filePath, fileName);
        
        //也可以这么写。
        //fs.writeFile(savedFilePath, fileContents, function() {
            //response.status(200).download(savedFilePath, fileName);
        //});
    复制代码

### 最后，前端访问下载推荐使用get,直接用a标签点击下载。如果用post就要创建一个a标签，点击一下，具体的百度谷歌吧。 ###

[参考1 stackoverflow][1 stackoverflow] [比较好的中文参考博客][Link 1]

转载于:https://juejin.im/post/5c920b36f265da6112563703

[github.com_SheetJS_js-]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2FSheetJS%2Fjs-xlsx%2Fissues%2F993
[github.com_expressjs_e]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2Fexpressjs%2Fexpress%2Fblob%2Fmaster%2Flib%2Fresponse.js%23L526
[1 stackoverflow]: https://link.juejin.im?target=https%3A%2F%2Fstackoverflow.com%2Fquestions%2F45922074%2Fnode-express-js-download-file-from-memory-filename-must-be-a-string
[Link 1]: https://link.juejin.im?target=https%3A%2F%2Faotu.io%2Fnotes%2F2016%2F04%2F07%2Fnode-excel%2Findex.html