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Using AWS S3 Buckets in a NodeJS App

Gonzalo P.
Jan 16, 2018 · 4 min read

AWS S3 is a simple storage service offered by Amazon AWS that give you the ability to use it as a webservice. Imagine a Dropbox or Google Drive that allows you to upload or download files programmatically with an API.

We will go through all the process of using a S3 with NodeJS, from creating the S3 Bucket and access credentials to actually use the bucket.

First, you need to know how a few concepts:

  • S3 Bucket: is a storage unit from the S3 service from Amazon. You can store different type of files (data) and have metadata that describes the actual data or file.
  • Access Key ID: Is the identification for a certain access key that allows an application or user to access a set of preconfigured AWS Resource (like a S3 Bucket for example).
  • Secret Access key: Is the secret part of the Access Key ID. Think of it as a password for a specific Access Key ID (they must be used always in pairs)

Now that we understand all of this concepts, we must configure the Amazon Console before start coding.

Step 1: Get your key pairs

The easy way to obtain a key pair is to create them for your default account for AWS Console.

Go to the top bar and click your user account

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Then, click in “My security credentials” and “Access keys”, finally, click “Create New Access Key”.

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A modal window should pop and it will tell you that your access key pairs have been created. Click in “Show access key” to see both of the keys

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Copy and store them in a secure place. We will use them later.

Step 2: Create a Bucket

Go to “Services/Storage/S3” and then click in “Create Bucket”.

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Then, fill the information required in the form. The bucket name must be unique, so be creative :)

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For this example we are leaving the properties and permissions with the default values

Click next, next, next and you will have the bucket created.

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The way that we will need to identificate the bucket is with the “Bucket name” (in this case is “creative-bucket-name-6355123”). So keep it in mind for later use.

Step 3: Creating a Node JS project an example file for upload

Before you start coding, let’s create the basic project.

Create a blank project using the command and typing the information required (project name, repo, licence, etc).

npm init

Then, create a folder in the root directory with the name “data” and create a text file called “file.txt” with the following content:

Hi, I am a file uploaded to S3 resource using NodeJS :)

Now, go to the root folder and write the following command to install the AWS Package of NPM inside the project.

npm install aws-sdk --save

Now, create a “index.js” file in the root folder and put the following content

Now, replace the following text:

  • Replace in Line 7, “<Access Key Here>” with the Access Key ID from the step 1.
  • Replace in Line 8, “<Secret Access Key Here>” with the Secret Access Keyfrom the step 1.
  • Replace in Line 16, “<Bucket Name here>” with your Bucket name created in the step 2.

All set, if you run “npm start” you should see a console message indicating the URL of the file uploaded. Go to your AWS console and check if your file is up.

The key parts of this code are:

  • Line 6: Access configuration
  • Line 12: File to upload
  • Line 15: Upload parameters
  • Line 21: Uploading file and response callback (second parameter with the function).
  • Line 23: Handling error

That’s it! you can leave questions or doubts that you could have in the comments area bellow and I will complement the post.

Happy coding!


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