README.md

Realtime HTTP/JSON Data Server

This NodeJS/Express module can serve JSON-SCADA realtime data for the web-based interface.

It can also server the HTML files from the src/htdocs folder.

It is possible to access Grafana on "/grafana" path adjusting the JS_GRAFANA_SERVER environment variable.

It is recommended to apply a reverse proxy (Nginx) on top of this service to serve securely to client on external networks. For best scalability static files should be served directly via Nginx or Apache, redirecting /grafana to the Grafana server and /Invoke to this Node.js service.

Example Nginx config as a reverse proxy

# data API
location /Invoke/ {
    proxy_set_header   X-Forwarded-For $remote_addr;
    proxy_set_header   Host $http_host;
    proxy_pass         http://127.0.0.1:8080/Invoke/;
}

# Grafana server
location /grafana/ {
    proxy_set_header   X-Forwarded-For $remote_addr;
    proxy_set_header   Host $http_host;
    proxy_pass         http://127.0.0.1:3000/;
}

# Supervisor web access, if desired
location /supervisor/ {
    proxy_set_header   X-Forwarded-For $remote_addr;
    proxy_set_header   Host $http_host;
    proxy_pass         http://127.0.0.1:9000/;
}

# Static files
location / {
    root /home/username/json-scada/src/htdocs;
}

Data Services API, File Services API

See https://github.com/riclolsen/json-scada/tree/master/src/server_realtime_auth#read-service.

Environment Variables

• JS_IP_BIND [String] - IP address for server to listen. Use "0.0.0.0" to listen on all interfaces. Default="localhost" (local host only).
• JS_HTTP_PORT [Integer] - HTTP Port for server listening. Default=8080.
• JS_GRAFANA_SERVER [Integer] - HTTP URL to the Grafana server (for reverse proxy on /grafana). Default="http://127.0.0.1:3000".
• JS_CONFIG_FILE [String] - JSON SCADA config file name. Default="../../conf/json-scada.json".
• JS_READ_FROM_SECONDARY [String] - Use "TRUE" to change the preferred read to a secondary MongoDB server. By default all read operations are directed to the primary server.

For connection to the PostgreSQL historian, it is possible to use the standard Libpq environment variables.

• https://www.postgresql.org/docs/current/libpq-envars.html

Command line arguments

This process has no command line arguments.