do-socket-service

This repository provides a simple server that forwards all messages received via a socket.io socket.

Installation

A Docker image is hosted on Dockerhub as datascienceinstitute/do-socket-service.

You can start a Docker container based on this image:

docker run -it -d --restart=always --name do-socket-service -p 8080:8080 datascienceinstitute/do-socket-service:latest

or via:

docker-compose up -d

Usage

The socket.io client is available at /socket.io.js endpoint.

Dynamic namespaces are supported and accessible with the do- prefix. These require authentication and are the recommended method for connecting sockets.

A legacy /sharedsocket namespace without authentication is also available, but is deprecated and scheduled for removal in the next release.

An admin UI for monitoring the socket server and its connections is available at the /admin endpoint, for further information please see the documentation provided by socket.io.

Please see the .env.example, config.example.json and credentials.example.json files, which provide sample setups for injecting environment variables, server configuration and authenticating users respectively.

Custom Behaviour

Sockets can come in two optional flavours, controllers and views. This follows the model used by the Open Visualisation Environment. The socket's type is provided via the socket' s data property. If unspecified, none of the custom behaviour below will be applied.

Alongside broadcasting messages to all sockets in the namespace, the server provides two events - __count__, __connect__ and __disconnect__.

Querying the server with a __count__ message will see it respond with a __count__ message containing the number of connected view sockets. Whenever a view socket connects, the __connect__ event is broadcast, notifying the remaining sockets of the disconnection. Whenever a view socket disconnects, the __disconnect__ event will be broadcast, notifying the remaining sockets of the disconnection.

These messages were implemented to enable the stateful sharing of computation across a pool of connections, as required by the controller/view model implemented by the .