Download AWS S3 file directly to a directory - node.js

Question

I want to automatically save the file im downloading from AWS S3 to my application folder. Right now this can be done manually. Code below:
router.get("/download", (req, res) => {
//File S3 URL
var fileKey =
"key";
AWS.config.update({
accessKeyId: IAM_USER_KEY,
secretAccessKey: IAM_USER_SECRET,
Bucket: BUCKET_NAME
});
var s3 = new AWS.S3();
var file = fs.createWriteStream("test.csv");
var options = {
Bucket: "name",
Key: fileKey
};
res.attachment(fileKey);
var fileStream = s3
.getObject(options)
.createReadStream()
.on("error", error => {
console.log(error);
res.json({ error: "An error has occured, check console." });
})
.on("httpData", function(data) {
file.write(data);
})
.on("httpDone", function() {
file.end();
});
fileStream.pipe(res);
// fse.writeFileSync("text.csv");
});
As mentioned before, the file can be download and saved manually. But how can write the file and save it automatically in an specific folder?
Thank you

Answer 1

Here's an example of downloading an S3 object to a specific local file:
const AWS = require('aws-sdk');
var s3 = new AWS.S3({apiVersion: '2006-03-01'});
var params = {Bucket: 'mybucket', Key: 'test.csv'};
var file = require('fs').createWriteStream('/tmp/test.csv');
s3.getObject(params).createReadStream().pipe(file);

Answer 2

The code for jarmod's answer, promisified:
const AWS = require('aws-sdk');
const s3 = new AWS.S3({apiVersion: '2006-03-01'});
const params = {Bucket: 'mybucket', Key: 'test.csv'};
const file = require('fs').createWriteStream('/tmp/test.csv');
new Promise((resolve, reject) => {
const pipe = s3.getObject(params).createReadStream().pipe(file);
pipe.on('error', reject);
pipe.on('close', resolve);
});