Image server

The image server is a simple nodejs express server that allows images to be uploaded with Multer and resizes the based on url scheme, resizing is done with the node-steam library.

See: https://github.com/Amsterdam/openstad-image-server

Http-bearer is used fo validating requests so only registered clients can upload images.

Knex migrations create the clients table for registering clients that are allowed to use the API.

Prerequisites

• Git

• Node.js and npm

• ImageMagick

• MySQL

Installation

1. Run npm install

npm i

2. Configure .env

DB_NAME=
DB_USER=
DB_PASSWORD=
PORT_API=
PORT_IMAGE_SERVER=
IMAGES_DIR=
THROTTLE_CC_PROCESSORS=4
THROTTLE_CC_PREFETCHER= 20
THROTTLE_CC_REQUESTS= 100
APP_URL=
CACHE_TTS=
CACHE_OPTIMIZED_TTS=
CACHE_OPTIMIZED_TTS=

For throttle see options in node-steam.

The app url is used to return a full url after upload.

Images directory defaults to images, if doesn't get created, create it manually.

3. Install knex globally

npm install knex -g

4. Run knex migration

knex migrate:latest

5. Add a client to mysql

See clients

6. Run the server

Run npm (or pm2, or whatever runner you use).

npm run start

Clients

For every site create a row in the MySQL clients table. Generate a random token that's safe. Currently there is no interface for creating so create it command line or through an mysql interface like sequelpro or phpmyadmin. The seed will generate one if the ENV values is

Uploading an image

Example with node.js, using node-fetch & form-data. Pass the access_token that you've generated for the client, can be in url or as header "Bearer: ${token}" make sure it's over HTTPS.

const FormData = require('form-data');
const fetch = require('node-fetch');

exports.upload = function (token, buffer, fileName) {
  const form = new FormData();
  form.append('image', buffer, fileName);
  form.append('field', 'files');

  return fetch(process.env.IMAGE_API_URL+ '/image?access_token=' + process.env.IMAGE_API_ACCESS_TOKEN, {
    method: 'POST',
    body: form,
  })
  .then(function(res) {
    return res.json();
  })
  .then(function(json) {
    //json.url
  })
  .catch(function(err) {
    // handle error
  })
}

Displaying & Resizing image

Example for creating a thumbnail resize and crop:

http://imageserver.com/image/path.png/:/rs=w:350,h:250;cp=w:350,h:250

For all options (resizing, cropping, filter, etc) check node-steam.