GeoCASe-thumbnail

The GeoCASe-UI 2.0 requires an image-server to generate thumbnails of images from various domains.

The docker-compose starts two services:

• An express server which queries:
• a h2non/Imaginary container for making images

Requirements

• docker
• docker-compose
• node.js

Build

docker-compose up starts the services and exposes http://localhost:2020. You can change the port in docker-compose.yml. Try out the endpoints to test if the service is running properly:

Enviroment variables

• THUMBNAIL_WIDTH, defined in docker-compose.yml.

Endpoints

• /
• /thumbnails: List all rendered thumbnails.
• /thumbnail?url=...: Generate a thumbnail. If it already exists a cached version will be returned. Add &force to the queryvariables to ignore the cache. The url should be encoded with encodeURIComponent or similar
• /thumbnail/delete?url=...: Delete a thumbnail. If url starts with an *{string}, it removes all thumbnails with an url containing {string}.

Services

Express

Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications.

Imaginary

Imaginary is a Fast HTTP microservice written in Go for high-level image processing backed by bimg and libvips. imaginary can be used as private or public HTTP service for massive image processing with first-class support for Docker & Fly.io. It's almost dependency-free and only uses net/http native package without additional abstractions for better performance.

Testing

Some test-urls were downloaded from GeoCASe 2.0. You can render an html file showing these images with:

npm install
node testdata
serve testdata

The first time you load the page the images need to be created. After reload they should come from the cache and display considerately faster.