AWS Lambda Image Resizer Demo

This example code shows image resizing, either based on binary input to an API Gateway and Lambda, or as an event-driven flow from images placed in an S3 subpath.

For the API Gateway case, it:

• Takes the binary input of a JPG image;
• converts it into a buffer;
• converts it according to your settings into a number of resized images using Sharp;
• and then puts them in an S3 bucket in designated area for resized files.

For the S3 event-driven case it does the same, but assumes that the input is a JPG file added to the original path of an S3 bucket.

All in all, the infrastructure used is API Gateway v2 (HTTP API), Lambda, and S3.

This example simplifies what has been a complicated and tricky process using Lambda Layers and other workarounds - doing it this way is much easier and more straightforward.

Prerequisites

It is assumed that:

• You have a recent Node.js version installed (ideally version 20 or later)
• You have an AWS account
• You have sufficient privileges to deploy infrastructure such as Lambda, API Gateway and S3 to AWS
• You are logged into AWS through your environment

Preparation

Make sure to set a unique value in serverless.yml for custom.imagesBucketName.

If you want to set the paths for where to locate the original files and the output destination, they are available under custom.imagesBucketPrefix (Default: original/) and custom.resizedImagesPath (Default: images-resized).

Also, you can change the resizing settings in src/handler.ts in the conversions object.

Local development

Run npm start.

Deployment

Run npm run deploy.

Remove the stack

Run npm run teardown.

Example call

Using the provided example image, you could call your API similar to this:

curl -X POST https://RANDOM.execute-api.REGION.amazonaws.com/ \
  -H "Content-Type: image/jpg" \
  --data-binary '@image.jpg'