node-shiny-proxy

node-shiny-proxy is a simple way to deploy R Shiny apps. It runs some instances of your Shiny app(s) using Rscript on your system and sets up a reverse proxy to expose them to your users. It relies on the popular http-proxy and http-proxy-middleware for proxying. As a pure Node.js solution it is platform-independent.

It is intended mainly as a proof of concept deployment option; for more robust solution you should go to Rstudio's Shiny Server or to ShinyProxy. However, depending on your needs, you may find some of its features useful:

it runs several instances of your Shiny apps to overcome the single-process limitation of the free version of Shiny Server,
it works cross-platform (where R and Node.js run) and does not rely on Java or Docker as ShinyProxy does,
it basically a middleware for a Node.js Express application, so it can be extended easily to suit your needs (authentication, etc.),
it can host different Shiny apps at "nested" paths (for instance one app at / and another at /some-app).

Installation

npm install --save shiny-proxy

Simple example

The following example will serve two Shiny apps located in the shiny-apps/main-app and shiny-apps/my-appfolders:

import express from 'express';
import ShinyProxy from 'shiny-proxy';

const shinyProxy = new ShinyProxy({
    portRangeStart: 4000,
    apps: [
        {
            id: 'main-app',
            path: '/',
            appDir: 'shiny-apps/main-app'
        },
        {
            id: 'my-app',
            path: '/my-app',
            appDir: 'shiny-apps/my-app'
        }
    ]
});

const app = express();

app.use(shinyProxy.middleware);

app.listen(3000);

Options

A shiny-proxy object is created with new ShinyProxy(options). This section described available options.

Main settings

options.portRangeStart: the start of the port range to serve Shiny apps instances on localhost (defaults to 4000). Shiny apps instances will be served on available tcp ports starting from there.
options.RscriptPath: the path to Rscript executable (by default, /usr/lib/R/bin/Rscript).
options.redirect404: the path to redirect "page not found" errors to (by default, /404).
options.redirect500: the path to redirect "internal server errors" to (by default, /500). On error, shiny-proxy will try to launch new instance of your apps.
options.apps: an array of Shiny apps settings.

Apps settings

options.apps[i].id: a unique string identifier for the Shiny app.
options.apps[i].path: the path to serve the Shiny app on.
options.apps[i].appDir: the path of the folder containing the Shiny app (with either app.R or server.R and ui.R).
options.apps[i].workers: the number of instances of the app to run (by default 2).

License

MIT License (MIT)