npm package: @resourcefulhumans/rheactor-image-service
Description: An image processing backend running on AWS Lambda.
Author: Resourceful Humans GmbH
Latest version: 3.1.0

# rheactor-image-service
  
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An image processing backend running on AWS Lambda.

Uses [gm](https://www.npmjs.com/package/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  |
|:--------:|:-------:|
| ![Original](./test/data/d4d4d4.jpg) | ![Result](./doc/d4d4d4-resized.jpg) |
| JPEG  | JPEG |
| 600x300  | 256x256 |
| ![Original](./test/data/d4d4d4.png) | ![Result](./doc/d4d4d4-png-resized.jpg) |
| PNG  | JPEG |
| 600x300  | 256x256 |
| ![Original](./test/data/11154d.jpg) | ![Result](./doc/11154d-resized.jpg) |
| JPEG  | JPEG | 
| 300x600  | 256x256 |

## Request

Users need to provide an [JsonWebToken](https://jwt.io/) 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**](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-install.html). 
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.