The Websocket reuires some node.js packages these can be installed via (in the websocket directory):

npm init -y

npm install redis
npm install ws
npm install dotenv

To run the Websocket, a libary like pm2 is recomendend.

npm install pm2 -g

To now start the Websocket use:

pm2 start index.js --max-memory-restart 1G --node-args="--max-old-space-size=1024" --name="WebSocket WKVS"

The --max-memory-restart and --max-old-space-size may be set higher, if many connections are predicted and the server has enough RAM.

All proesses of pm2 can be listed via:

pm2 list

To stopp the Websocket and remove it from pm2, use:

pm2 stop "WebSocket WKVS"

pm2 remove "WebSocket WKVS"

The whole PHP code depends on multiple composer packages. To install these create a folder composer in the document root:

mkdir composer && cd composer

Then install the composer packages:

composer require vlucas/phpdotenv &&
composer require phpmailer/phpmailer &&
composer require shuchkin/simplexlsx &&
composer require sprain/swiss-qr-bill &&
composer require james-heinrich/getid3 &&
composer require chriskonnertz/string-calc &&
composer require tecnickcom/tcpdf

WKVS was developed with the folowing versions:

vlucas/phpdotenv 5.6
phpmailer/phpmailer 7.0
shuchkin/simplexlsx 1.1
sprain/swiss-qr-bill 5.3
james-heinrich/getid3 1.9
chriskonnertz/string-calc 2.0
tecnickcom/tcpdf 6.11