Objective
The NodeJS Middleware provides the ability to modernize existing API with SOAJS when this API is built using NodeJs as a development language.
The middleware exposes several functionality and configuration that SOAJS offers and which can be consumed by the API upon initialization or during runtime when requests arrive.
This page explains the NodeJs middleware; the functionality and configuration that it offers, how to install it and how to use it.
Scenario
- How to Install
- Features
- Configuration
- Functionality
- How does it work
- on init
- on request
- Using the Middleware
- Initialization State
- Runtime State
- Examples
- NodeJs Express
- NodeJs Hapi
1- How to Install
The SOAJS NodeJs middleware is open source and is available under Github, you can use the following reference to pull the source code → https://github.com/soajs/soajs.nodejs
The middleware is also available as an NPM package and can be download for free.
# install from npm npm install soajs.nodejs
The middleware can also be used as a dependency in your package.json file
{ "dependencies": { "soajs.nodejs": "*" } }
2- Features
Once the middleware is initialized, the following functionality becomes available:
Function | Type | Input | Output | Remarks |
---|---|---|---|---|
getDatabases | Method | dbName (optional) |
| Mongo Client Driver |
getServiceConfig | Method | - | returns service configuration object | Services Config |
getDeployer | Method | - | returns deployer object | Registry |
getCustom | Method | - | returns custom object | Services Config |
getResources | Method | resourceName (optional) |
| Registry |
getServices | Method | serviceName (optional) |
| Service |
getDaemons | Method | daemonName (optional) |
| Daemon |
reload | Method | - | void (reload registry only) | Registry |
This middleware functionality is accessible via the request that is made to the API. The middleware traps the request once it hits the API, injects its functionality and then hands it back to you to add your business logic.
3-How does it work
On Init
The Middleware requires the following environment variables to be set prior to starting your service
Environment Variable | Description | Example | Reference |
---|---|---|---|
SOAJS_REGISTRY_API | The location of the SOAJS API Gateway along with the maintenance port value that it is using in the environment where the service will run in | 127.0.0.1:5000/ | Environment Variables |
SOAJS_ENV | environment code that this service will run in | DEV | Environment Variables |
Once your service starts, the middleware will make a call to the SOAJS API Gateway and retrieve the registry of the environment, it will cache it in memory.
From this registry, it uses variable autoReloadRegistry (which represents the auto reload duration in seconds) and every time this value is met, the middleware automatically pulls the new version of the registry and updates its cached version.
On request
SOAJS midlleware augments your service by trapping all arriving requests and injecting additional data then hands the updated version of request to your business logic.
The following table illustrates the data that gets injected by the middleware on every request:
Property | Code Snippet | Description | Reference |
---|---|---|---|
Tenant | req.soajs.tenant tenant : { id : '', code : '' } | Represents the tenant that is making the call to the API. | Multitenancy |
Key Device Geo | req.soajs[ key | device | geo ] key : { config : {}, iKey : '', eKey : '' }, device : '', geo : {} | Represents the key configuration which belongs to the tenant making the call to the API. | |
Application | req.soajs.application application : { product : '', package : '', appId : '', acl : {}, acl_all_env : {} } | Represents the application information which belongs to the tenant making the call to the API. | |
Package | req.soajs.package package :{ acl :{}, acl_all_env : {} } | Represents the Productization that the tenant making the call to the API is using. | |
URAC | req.soajs.urac urac : {} | Represents the User whose access token was found in the request. | URAC v2 |
Awareness | req.soajs.awareness awareness : { host : '', port : '', getHost : 'function' } | Represents the SOAJS API Gateway internal network host & port based on the environment where the API is deployed and running in. | Request |
4- Using the Middleware
Once you download the middleware, simply require it and instruct the web application server to use it.
Consequently, anywhere in your APIs, invoke req.soajs to access the data and functions that it offers.
// require the mw const soajsMW = require('soajs.nodejs'); // pass it to your service app app.use(soajsMW({ serviceName : 'my_service' })); //... // invoke req.soajs app.post('/foo', (req, res) => { //... let soajs = req.soajs; console.log( JSON.stringify( soajs, null, 2 ) ); //... });
5- Examples
NodeJs Express
The following code snippets shows a basic example built using NodeJs Express Library and how the SOAJS NodeJs Middleware was added to the code to augment the web server created by express.
Full Example on: https://github.com/soajs/soajs.nodejs.express
'use strict'; //Create Express App const express = require('express'); const app = express(); //Require SOAJS Middleware for NodeJs const soajsMW = require('soajs.nodejs'); const url = require('url'); //Instruct the Express App to use the SOAJS Middleware app.use(soajsMW({ serviceName : 'my_service' })); //Invoke the middleware and use it in the Express app API app.get('/hello', (req, res) => { let url_parts = url.parse(req.url, true); let query = url_parts.query; let username = query.username; let lastname = query.lastname; res.send({ "message": `Hello DEMO, I am an EXPRESS service, you are [ ${username} ] and your last name is : [ ${lastname} ]`, "dbs" : req.soajs.reg.getDatabases() }); }); //Invoke the middleware and use it in the Express app API app.post('/hello', function(req, res){ let response = req.soajs; req.soajs.awareness.getHost( (host) => { response.controller = host; res.send(response); }); }); //Start the Express app and set it to listen on port 4382 app.listen(4382);
NodeJs Hapi
The following code snippets shows a basic example built using NodeJs Hapi Library and how the SOAJS NodeJs Middleware was added to the code to augment the web server created by hapi.
Full Example on: https://github.com/soajs/soajs.nodejs.hapi
'use strict'; const url = require('url'); //Create Hapi App const Hapi = require('hapi'); const server = new Hapi.Server(); //Instruct the Hapi app to listen on port 4380 server.connection({ host: '0.0.0.0', port: 4380 }); //Require SOAJS Middleware for NodeJs const soajsMW = require('soajs.nodejs')({serviceName : 'my_service'}); //Instruct the Hapi App to use the SOAJS Middleware server.ext({ type: 'onRequest', method: (request, reply) => { soajsMW(request, reply, (err) => { if (err) { throw err; } return reply.continue(); }); } }); //Invoke the middleware and use it in the Express app API server.route({ method: 'GET', path: '/hello', handler: (request, reply) => { let url_parts = url.parse(request.url, true); let query = url_parts.query; let username = query.username; let lastname = query.lastname; return reply({ "message": `Hello DEMO, I am an Hapi service, you are [ ${username} ] and your last name is : [ ${lastname} ]`, "dbs" : req.soajs.reg.getDatabases() }); } }); //Invoke the middleware and use it in the Express app API server.route({ method: 'POST', path: '/tidbit/hello', handler: (request, reply) => { let response = request.soajs; request.soajs.awareness.getHost( (host) => { response.controller = host; return reply(response); }); } }); //Start the Hapi app server server.start((err) => { if (err) { throw err; } console.log('Server running at:', server.info.uri); });
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