使用 Nodejs Lambda 从 S3 上的 .xlsx 文件中读取数据

Question

I'm still new in NodeJs and AWS, so forgive me if this is a noob question.

I am trying to read the data from an excel file (.xlsx). The lambda function receives the extension of the file type.

Here is my code:

exports.handler = async (event, context, callback) => {
    console.log('Received event:', JSON.stringify(event, null, 2));
    if (event.fileExt === undefined) {
        callback("400 Invalid Input");
    }
    
    let returnData = "";
    const S3 = require('aws-sdk/clients/s3');
    const s3 = new S3();
    

    switch(event.fileExt)
    {
        case "plain":
        case "txt":
            // Extract text
            const params = {Bucket: 'filestation', Key: 'MyTXT.'+event.fileExt};
            
            try {
                await s3.getObject(params, function(err, data) {
                  if (err) console.log(err, err.stack); // an error occurred
                  else{           // successful response
                      returnData = data.Body.toString('utf-8');
                      context.done(null, returnData);
                  }
                }).promise();
        
            } catch (error) {
                console.log(error);
                return;
            }  
           
            break;
        case "xls":
        case "xlsx":
            returnData = "Excel";
            // Extract text
            
            const params2 = {Bucket: 'filestation', Key: 'MyExcel.'+event.fileExt};
            const readXlsxFile = require("read-excel-file/node"); 
            
            try {     
                const doc = await s3.getObject(params2);     
                const parsedDoc = await readXlsxFile(doc);     
                console.log(parsedDoc)   
            } catch (err) {     
                console.log(err);     
                const message = `Error getting object.`;     
                console.log(message);     
                throw new Error(message);   
            } 
            
            break;
        case "docx":
            returnData = "Word doc";
            // Extract text
            break;
        default:
            callback("400 Invalid Operator");
            break;
    }
    callback(null, returnData);
};

The textfile part works. But the xlsx part makes the function time out. I did install the read-excel-file dependency and uploaded the zip so that I have access to it. But the function times out with this message: "errorMessage": "2020-11-02T13:06:50.948Z 120bfb48-f29c-4e3f-9507-fc88125515fd Task timed out after 3.01 seconds"

Any help would be appreciated! Thanks for your time.

Answer 1

using the xlsx npm library. here's how we did it.

assuming the file is under the root project path.

const xlsx = require('xlsx');

// read your excel file
let readFile = xlsx.readFile('file_example_XLSX_5000.xlsx')

// get first-sheet's name
let sheetName = readFile.SheetNames[0];

// convert sheets to JSON. Best if sheet has a headers specified.
console.log(xlsx.utils.sheet_to_json(readFile.Sheets[sheetName]));

Answer 2

You need to install xlsx (SheetJs) library into the project: npm install xlsx

and then import the "read" function into the lambda, get the s3 object's body and send to xlsx like this:

const { read } = require('sheetjs-style');
const aws = require('aws-sdk');
const s3 = new aws.S3({ apiVersion: '2006-03-01' });

exports.handler = async (event) => {
    const bucketName = 'excel-files';
    const fileKey = 'Demo Data.xlsx';

    // Simple GetObject
    let file = await s3.getObject({Bucket: bucketName, Key: fileKey}).promise();
    const wb = read(file.Body);

    const response = {
        statusCode: 200,
        body: JSON.stringify({
            read: wb.Sheets,
        }),
    };
    return response;
};

(of course, you can receive the bucket and filekey from parameters if you send them...)

Very Important: Use the READ (not the readFile) function and send the Body property (with capital "B") as a paremeter

Answer 3

I changed the timeout to 20 seconds and it works. Only one issue remains: const parsedDoc = await readXlsxFile(doc); wants to receive a string (filepath) and not a file.

Answer 4

Solved by using xlsx NPM library. Using a stream and giving it buffers.