Download xlsx from S3 and parse it

Question

I need a service to download an excel file from Amazon S3, then parse with node-xlsx

The problem is that I can\'t get xlsx to parse the file. When I try to read back

Answer 1

If you want use async/wait, here solution:

    const AWS = require('aws-sdk');
    const XLSX = require('xlsx');

    AWS.config.update({
      accessKeyId: AMAZON_ACCESS_KEY,
      secretAccessKey: AMAZON_SECRET_ACCESS_KEY,
    });

    // Get buffered file from s3    
    function getBufferFromS3(file, callback){
      const buffers = [];
      const s3 = new AWS.S3();
      const stream = s3.getObject({ Bucket: 'yor_buket', Key: file}).createReadStream();
      stream.on('data', data => buffers.push(data));
      stream.on('end', () => callback(null, Buffer.concat(buffers)));
      stream.on('error', error => callback(error));
    }

    // promisify read stream from s3
    function getBufferFromS3Promise(file) {
      return new Promise((resolve, reject) => {
        getBufferFromS3(file, (error, s3buffer) => {
          if (error) return reject(error);
          return resolve(s3buffer);
        });
      });
    };

    // create workbook from buffer
    const buffer = await getBufferFromS3Promise(file);
    const workbook = XLSX.read(buffer);


    // If you want to send the workbook as a download to the api end point in node
    const fileName = "Categories.xlsx";
    res.setHeader('Content-disposition', 'attachment; filename=' + fileName);
    res.setHeader('Content-type', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
    const wbout = XLSX.write(workbook, { bookType: 'xlsx', type: 'buffer'});
    res.send(new Buffer(wbout));