Migrate GetObject (v2) to GetObjectCommand (v3) - aws-sdk - amazon-web-services

Question

I'm trying to migrate an Express endpoint from v2 to v3 of the aws-sdk for JavaScript. The endpoint is a file downloader for AWS S3.
In version 2, I passed the result of GetObject back to the browser in a readable stream. In version 3 that same technique fails with the error:
TypeError: data.Body.createReadStream is not a function
How do I work with the data that returned from the new GetObjectCommand? Is it a blob? I'm struggling to find anything useful in the v3 SDK docs.
Here are the two versions of the endpoint:
import AWS from 'aws-sdk'
import dotenv from 'dotenv'
import { GetObjectCommand, S3Client } from '#aws-sdk/client-s3'
dotenv.config()
// VERSION 3 DOWNLOADER - FAILS
const getFileFromS3v3 = async (req, res) => {
const client = new S3Client({ region: 'us-west-2' })
const params = {
Bucket: process.env.AWS_BUCKET,
Key: 'Tired.pdf',
}
const command = new GetObjectCommand(params)
try {
const data = await client.send(command)
console.log(data)
data.Body.createReadStream().pipe(res)
} catch (error) {
console.log(error)
}
}
// VERSION 2 DOWNLOADER - WORKS
const getFileFromS3 = async (req, res) => {
const filename = req.query.filename
var s3 = new AWS.S3()
var s3Params = {
Bucket: process.env.AWS_BUCKET,
Key: 'Tired.pdf',
}
// if the file header exists, stream the file to the response
s3.headObject(s3Params, (err) => {
if (err && err.code === 'NotFound') {
console.log('File not found: ' + filename)
} else {
s3.getObject(s3Params).createReadStream().pipe(res)
}
})
}
export { getFileFromS3, getFileFromS3v3 }

Answer 1

This version 3 code works. Thanks to a major assist, the trick was to pipe data.Body and not use any of the fileStream methods.
import { GetObjectCommand, S3Client } from '#aws-sdk/client-s3'
import dotenv from 'dotenv'
dotenv.config()
const getFileFromS3 = async (req, res) => {
const key = req.query.filename
const client = new S3Client({ region: process.env.AWS_REGION })
const params = {
Bucket: process.env.AWS_BUCKET,
Key: key,
}
const command = new GetObjectCommand(params)
try {
const data = await client.send(command)
data.Body.pipe(res)
} catch (error) {
console.log(error)
}
}
export { getFileFromS3 }
When called from this frontend function the code above returns the file from S3 to the browser.
const downloadFile = async (filename) => {
const options = {
url: `/api/documents/?filename=${filename}`,
method: 'get',
responseType: 'blob',
}
try {
const res = await axios(options)
fileDownload(res.data, filename)
} catch (error) {
console.log(error)
}
}