Remote Model

A fetcher for an externally hosted config file, that is released on a different cadence to your service

Written in javascript, for node based projects.

Features

• Auto update after n milliseconds (default, 5 minutes)
• Synchronous call caching
• Hot caching
• Can use any async method inplace of the network operation

Benefits of this approach - multiple callers can request data, but only one network call will be made. This ensures that all parts of your application receive the latest data at the same time.

Quickstart

Install:

npm install --save remote-model

Default behaviour with URL

HTTPS Usage, e.g. download file from remote host:

import remoteModel from 'remote-model'

const myModel = remoteModel({
  url: 'https://raw.githubusercontent.com/connected-web/remote-test/master/info.json',
  updateIntervalMs: 10 * 60 * 1000 // 10 minutes
})

myModel.fetch().then((data) => {
  console.log('[My Model]', data)
})

myModel.notify((data) => {
  console.log('[My Model] Updated', data)
})

Using a custom fetch function

Custom fetch usage, e.g. on a local filesystem:

import remoteModel from 'remote-model'
import fs from 'fs/promises'

const myModel = remoteModel({
  async fetcher() {
    return fs.readFile('local-model-to-watch.json', 'utf8')
  },
  updateIntervalMs: 2 * 60 * 1000 // 2 minutes
})

myModel.fetch().then((data) => {
  console.log('[My Custom Fetch Model]', data)
})

myModel.notify((data) => {
  console.log('[My Custom Fetch Model] Updated', data)
})

HTTPS Agent

In order to access content securely over HTTPS, the https lib is used to create a https agent for network requests. It is recommended that you set up the following environment variables prior to running your script. By default, the script expects the CLIENT_CERT, CLIENT_KEY, and CLIENT_CA to exist, for example:

export CLIENT_CERT="/user/certs/path.crt"
export CLIENT_KEY="/user/certs/path.key"
export CLIENT_CA="/user/certs/ca_bundle.crt"

Changelog

2.0.0

• Change project type to module
• Rewrite require to use module imports
• Rewrite tests to use module imports
• Change process.env to import.meta.env

1.1.1

• Dependabot patches to package dependencies
• Please consider upgrading to ^2.0.0

1.1.0

• Add support for custom fetch function
• Remote model can now cache any execute kind of asynchronous fetch operating
• Updated code base to use Node 14 LTS features

1.0.3

• Fix promise rejection on outstanding promises

1.0.2

• Add information about HTTPS Agent

1.0.1

• Add repository information to package.json

1.0.0

• Extracted first version from existing project
• Added tests for fetch and notify