fh-rest-sync-proxy

Minimalist FH.Sync integrations, from a Cloud Application, that retrieve data from a RESTful API running on a Red Hat Mobile MBaaS Service.

You can read more about the FH.Sync API here. Essentially this module automatically implements the sync.handleList, sync.handleRead, etc. for you.

Install

To use this module you must have fh-mbaas-api version 5.0.0 or higher installed in your package.json. Install example is below.

npm install fh-mbaas-api@5.X --save

This module is not yet published to npm, but you can install from GitHub as shown below. (Only tested using npm CLI version 3)

npm install feedhenry-staff/fh-rest-sync-proxy

Usage

Barebones Example

This example initialises your Cloud Application so that it can serve FH.Sync calls for a Client Application requesting the dataset "orders".

var mbaasSync = require('fh-rest-sync-proxy');

// Create a sync object that communicates with a service
var serviceSync = sync({
  guid: 'jsgduuQ50ZtF6iR3xuaacGvn',
  timeout: 15000
});

var syncOpts = {
  // Place the usual sync options here
  sync_frequency: 10,
  logLevel: 'error'
};

// Intialise a tickets dataset. Any sync calls for "tickets" will be
// routed to the MBaaS Service with guid "jsgduuQ50ZtF6iR3xuaacGvn"
serviceSync.initDataset('orders', syncOpts, function (err) {
  if (err) throw err; // Throw error, or retry init of sync
});

Full Example

This is the same as the previous example, but shows a full Cloud Application entry point.

'use strict';

var express = require('express')
  , mbaasApi = require('fh-mbaas-api')
  , mbaasExpress = mbaasApi.mbaasExpress()
  , app = module.exports = express()
  , mbaasSync = require('fh-rest-sync-proxy')
  , log = require('fh-bunyan').getLogger(__filename);

log.info('starting application');

// Note: the order which we add middleware to Express here is important!
app.use('/sys', mbaasExpress.sys([]));
app.use('/mbaas', mbaasExpress.mbaas);

// Note: important that this is added just before your own Routes
app.use(mbaasExpress.fhmiddleware());

//
app.use('/my-route', require('./routes/my-route'));

// Important that this is last!
app.use(mbaasExpress.errorHandler());


// Create a sync object that communicates with a service
var serviceSync = mbaasSync({
  guid: 'jsgduuQ50ZtF6iR3xuaacGvn',
  timeout: 15000,

  // remove property for a non nested API, e.g /path-to-nested-data-set/orders, vs. /orders
  pathToPrepend: 'path-to-nested-data-set'
});

var syncOpts = {
  // Place the usual sync options here
  sync_frequency: 10,
  logLevel: 'error'
};

// Intialise a orders dataset. Any sync calls for "orders" will be
// routed to the MBaaS Service with guid "jsgduuQ50ZtF6iR3xuaacGvn"
// and the result sent back to the client automatically, e.g
// sync read will go to GET /orders/:id on the service
serviceSync.initDataset('orders', syncOpts, function (err) {
  if (err) throw err; // Throw error, or retry init of sync

  var port = process.env.FH_PORT || process.env.VCAP_APP_PORT || 8001;

  app.listen(port, function() {
    log.info('app started on port: %s', port);
  });
});

Prerequisites

Before adding this module to your Cloud Application you must have created an MBaaS Service that exposes a RESTful API that can be used to query data from a backend store.

If this sounds daunting, fear not; we are working on adapters that can expose common backend stores in the correct format. We'll add a list here soon!

API

module(opts)

Create a sync proxy instance. Supported options are:

[REQUIRED] guid - appId/guid of the MBaaS Service you are making calls to [OPTIONAL] timeout - time to wait before considering a call to opts.guid as timed out [OPTIONAL] pathToPrepend - By default the dataset passed to initDataset is used as the URL to get data, e.g /orders, but you might need a nested path such as /branches/orders. If this is required place "/branches" or your equivalent in opts.pathToPrepend

Module calls return an instance.

instance.initDataset(dataset, syncOptions, callback)

Function used to enable sync passthrough/proxy to the MBaaS identified by opts.guid passed to module(opts). Arguments:

(String) dataset - The name of the dataset being exposed for sync (Object) syncOptions - Options for the underlying fhMbaasApi.sync call. Detailed info here (Function) callback - Called once initialisation is complete

Required MBaaS HTTP API Definition

For sync calls to succeed, your HTTP API must match the structure that sync expects. To easily create APIs like the one below you can use fh-rest-express-router.

In the below examples dataset-name can be anything you like, e.g "orders", "jobs", or "users".

GET /dataset-name

Generic list endpoint that returns an Object containing key value pairs based on a querystring. Keys must be unique IDs and values must be Objects.

Sample URL: GET /users?group=admin

Sample response:

{
  "02833": {
    "group": "admin",
    "firstname": "shadow",
    "lastname": "man"
  },
  "02834": {
    "group": "admin",
    "firstname": "red",
    "lastname": "hat"
  }
}

GET /dataset-name/:id

Returns an Object from the store based on the passed id.

Sample URL: GET /users/02834

Sample response:

{
  "group": "admin",
  "firstname": "red",
  "lastname": "hat"
}

POST /dataset-name/

Accepts an Object that contains data to create a new entry in the backend store. Returns the created Object data and unique ID (uid).

Sample URL: POST /users

Sample response:

{
  "uid": "02834",
  "data": {
    "group": "admin",
    "firstname": "red",
    "lastname": "hat"
  }
}

PUT /dataset-name/:id

Accepts an Object that contains data to update an entry in the backend store. Returns the updated Object.

Sample URL: PUT /users/02834

Sample response:

{
  "firstname": "red",
  "lastname": "hatter"
}

DELETE - /dataset-name/:id

Deletes the data associated with the given id from the backend store. Returns the deleted data.

Sample URL: DELETE /users/02834

Sample response:

{
  "group": "admin",
  "firstname": "red",
  "lastname": "hat"
}

Contributors

• Evan Shortiss
• Jim Dillon

Contributing Guide

Open an Issue to discuss ideas/bugs or get in touch via other means if desired. Alternatively open a PR if you feel you have a feature/fix that does not need significant discussion.

Be sure that running npm test passes for any PR opened!