@resourcefulhumans/rheactor-image-service

rheactor-image-service

An image processing backend running on AWS Lambda.

Uses gm with GraphicsMagick (which is available by default) on AWS lambda.

It takes JPEG or PNG images that are uploaded base64 encoded, crops and resizes them on the fly to 256x256px size, and stores them on an S3 bucket.

Original	Result
JPEG	JPEG
600x300	256x256
PNG	JPEG
600x300	256x256
JPEG	JPEG
300x600	256x256

Request

Users need to provide an JsonWebToken which is checked against the configured public key.

POST /upload
Content-Type: application/vnd.resourceful-humans.rheactor-image-service.v1+json
Authorization: Bearer <token>

{
  "$context":"https://github.com/ResourcefulHumans/rheactor-image-service#Upload",
  "image":"R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7",
  "mimeType":"image/png"
}

Response

Content-Type: application/vnd.resourceful-humans.rheactor-image-service.v1+json

{
  "$context":"https://github.com/ResourcefulHumans/rheactor-image-service#UploadResult",
  "url":"https://s3.eu-central-1.amazonaws.com/rheactor-image-service/example.com/33f24f55-e435-4198-a148-fdd1095ffa96-user-5.jpg",
  "mimeType":"image/jpeg"
}

This implementation expects token's sub to be an URL, which will be used to prefix and suffix URLs. A sub value of https://example.com/user/5 was used in the example above.

Configuration

These environment variables need to be set on the lambda function:

• S3_BUCKET
  Name of the S3 bucket, e.g. rheactor-image-service to where files are uploaded.
• S3_REGION
  Region to use.
• MOUNT_URL
  Public endpoint for the lamba function (as provided by API Gateway)
• WEB_LOCATION
  Public URL for the bucket
• PUBLIC_KEY_FILE
  Public key file in the bucket to be used for verifying tokens

Setup

npm install

# Configure these environment variables
AWS_ROLE=…
AWS_ACCESS_KEY_ID=…
AWS_SECRET_ACCESS_KEY=…
AWS_REGION=…
AWS_FUNCTION_NAME=…
NODE_ENV=…
VERSION=…

# install this as a new lambda function
make install

Local testing

For local testing use AWS SAM CLI. It has docker as a dependency. To start local testing run sam local start-api command. It will read template.yml and create local container with built function. It is required to build the project first - all files must be in build folder.

Because lambda function is not setting any additional CORS headers, easiest way is to use nginx to append them. Config for that is included in repo.