How to upload files to S3 from Node.js

Jun 22, 2021

Learn how to upload files to AWS S3 from Node.js: create a bucket and an IAM user, store the keys in .env, then send the file with the aws-sdk s3.upload().

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I had a simple use case.

I was building a job board and it was time to build the form to submit a new job offer.

The recruiter can enter the company details, the job details, and the company logo image.

The data is stored in the database, and at first I tried to store the logo in the database, but after a while I realized that while technically ok, I had some issues with storing the binary data and it was taking too long for the task. So I said, “ok let’s just upload it to S3”.

S3 is one of the wonderful services provided by AWS. Since I already use AWS for other things, adding a S3 bucket is easy.

So I went to create an S3 bucket.

I already had an AWS account. If you don’t, start here: https://aws.amazon.com.

Once you have an account set up, create a IAM user in AWS. Login to AWS, click your name on top and then “My Security Credentials”

AWS console dropdown menu showing My Security Credentials option

On the sidebar click “Users”, and “Add user”. Enable “Programmatic access”.

AWS Add user form with Programmatic access checkbox selected

Move to the next screen via the buttons you find in the bottom of the page (“Next: Permissions”).

Click the “Attach existing policies directly”:

AWS IAM permissions screen with Attach existing policies directly option highlighted

Type “S3” in the filter to show the S3 policies

AWS IAM policies filtered by S3 showing Amazon S3 related policies

Select the AmazonS3FullAccess permission:

AWS IAM policies list with AmazonS3FullAccess policy selected

Once the user is created, you’ll have a pair of access key ID and secret access key. Copy those to your .env file in the project you have, or store them somewhere so you can use them later.

Next, go in S3 and create a bucket. From the S3 homepage https://s3.console.aws.amazon.com click the “Create bucket” button.

Set a name, choose an AWS region, disable “Block all public access” (we’ll get to permissions in another post) and click the Create bucket button at the bottom of the page.

AWS S3 Create bucket form with bucket name and region settings

Done! Now it’s time to dive into Node.js. I use this code in Next.js, server side, in an API call.

First install the aws-sdk package with npm install aws-sdk.

As mentioned, store your AWS access codes in .env:

AWS_ACCESS_KEY_ID=<the access key>
AWS_SECRET_ACCESS_KEY=<the secret>
AWS_BUCKET_NAME=<the bucket name>

Add

import AWS from 'aws-sdk'

on top.

Then initialize the s3 object with:

const s3 = new AWS.S3({
  accessKeyId: process.env.AWS_ACCESS_KEY_ID,
  secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY
})

Now when you want to upload a file, load it from the storage

const filename = 'the-file-name'
const fileContent = fs.readFileSync(fileName)

const params = {
  Bucket: process.env.AWS_BUCKET_NAME,
  Key: `${filename}.jpg`,
  Body: fileContent
}

s3.upload(params, (err, data) => {
  if (err) {
    reject(err)
  }
  resolve(data.Location)
})

Tagged: Node.js · All topics

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