node-red-storage-hooks

Hook into Node-Red's storage API from your settings.js

What is it?

A storage plugin for Node-Red for when you want to hook into any of it's storage functions without writing an entire module yourself.

Why?

As an example: when you have a read-only filesystem you could use this to make your filesystem writable as a pre-hook and read-only again as a post-hook.

How to use?

Install using npm install node-red-storage-hooks from your node-red folder. Then edit your settings file and add storageModule: require("node-red-storage-hooks"). By default it uses the default localStorage plugin built in Node-RED. To use another storage plugin use: storageModule: require("node-red-storage-hooks").with('a-custom-storage-plugin')

API Hooks

Each of the API methods described by Node-RED has a hook, these can be found at https://nodered.org/docs/api/storage/methods/. Look there if you want to find out the function parameters. There's also a general pre-write hook, a post-write hook, a pre-read hook and a post-read hook. These are called outside of the specific hooks (for example: 1: pre-write, 2: pre-saveFlows, 3: actual save, 4: post-saveFlows, 5: post-write)

To hook into a function you can use pre_<function-name>: function(...parameters) { console.log('I'm in a pre-hook!'); }. Your hooks should return a promise that resolves the object you want to pass into the original localStorage plugin.

Examples

const fs = require('fs');

const settings = {
  storageModule: require("node-red-storage-hooks"),
  pre_saveFlows: (flows) => {
    return new Promise((resolve, reject) => {
      fs.writeFile('/home/foo/bar.json', JSON.stringify(flows), (err) => {
        if (err) { reject(err); }
        else { resolve(flows); }
      });
    });
  }
};