Storage API

The Storage API provides a pluggable way to configure where the Node-RED runtime stores data.

The information stored by the API includes:

• flow configuration
• flow credentials
• user settings
• user sessions
• node library content

By default, Node-RED uses a local file-system implementation of this API.

The API functions are documented here.

Configuration

The storageModule property in settings.js can be used to identify a custom module to use:

storageModule: require("my-node-red-storage-plugin")

Promises

The API makes extensive use of JavaScript promises.

A promise represents the eventual result of an asynchronous operation. It acts as a placeholder until the result is available.

Node-RED uses the When.js library. The following example shows it in use. For a more complete example, the default file-system implementation is located in red/runtime/storage/localfilesystem.js.

function getFlows() {
    // create and return a promise
    return when.promise(function(resolve,reject) {
        // resolve - a function to be called with the successful result
        // reject - a function to be called if an error occurs
    
        // do some asynchronous work, with a callback on completion
        doAsyncWork(function(err,result) {
            if (err) {
                reject(err);
            } else {
                resolve(result);
            }
        });
    });
}

getFlows()
    .then(function(result) {
        // Called when getFlows completes successfully
    })
    .otherwise(function(err) {
        // Called when getFlows hits an error
    });