NodeJs MW

Objective

The NodeJS Middleware provides the ability to modernize existing API with SOAJS when these APIs are built using NodeJs as a development language.

The middleware exposes several functionality and configuration that SOAJS and which can be consumed by the Microservice upon initialization or during runtime when requests to its APIs 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
1. Configuration
2. Functionality
How does it work
1. on init
2. on request
Using the Middleware
1. Initialization State
2. Runtime State
Examples
1. NodeJs Express
2. NodeJs Hapi

1- How to Install

Source Code: https://github.com/soajs/soajs.nodejs

// install from npm
npm install soajs.nodejs

// require it in your project
const soajsMW = require('soajs.nodejs');

2- Features

Once the mw is initialized, the following list of functions will be available to use through 'req.soajs.reg'

Function	Input	Output	Remarks
getDatabases	dbName (optional)	returns database object if dbName provided returns all core and tenant meta databases otherwise	Mongo Client Driver
getServiceConfig	-	returns service configuration object	Services Config
getDeployer	-	returns deployer object
getCustom	-	returns custom object	Services Config
getResources	resourceName (optional)	returns resource object if resourceName provided returns all resources otherwise
getServices	serviceName (optional)	returns service object if serviceName provided returns all services otherwise	Service
getDaemons	daemonName (optional)	returns daemon object if daemonName provided returns all daemons otherwise	Daemon
reload	-	void (reload registry only)	Registry

3-How does it work

On Init:

Using the following environment variables:

```
SOAJS_REGISTRY_API
```

```
SOAJS_ENV
```

the middleware is going to invoke the controller and get the registry. Using the service configuration provided, the mw will auto reload the registry every "serviceConfig.awareness.autoRelaodRegistry"

Once the registry is loaded, the middleware is now ready to act on request.

On request:

Once a request is reached, the SOAJS controller will be passing through the request headers a 'soajsinjectobj' which will be mapped within the middleware to the following standard object:

{
  tenant : {
    id : '',
    code : ''
  },
  key : {
    config : {},
    iKey : '',
    eKey : ''
  },
  application : {
    product : '',
    package : '',
    appId : '',
    acl : {},
    acl_all_env : {}
  },
  package :{
    acl :{},
    acl_all_env : {}
  },
  device : '',
  geo : {},
  urac : {},
  awareness : {
    host : '',
    port : '',
    getHost : 'function'
  }
}

Hence you can now use the set of functions appended to req.soajs.reg (shown in features)

4- Using the Middleware

Require this Middle Ware in your restful nodejs service, and append it to your app.

Consequently, anywhere in your APIs you can get your soajs object and use the data / functions as follows:

// require the mw
const soajsMW = require('soajs.nodejs');

// pass it to your service app
app.use(soajsMW({
	serviceName : 'test'
}));

// use it in your requests
app.post('/helloworld', function(req, res){ 
	var soajs = req.soajs;
	// soajs.key.iKey;
	// soajs.reg.getDatabases(); });
});

5- Examples

Express Example

'use strict';

var express = require('express');
var app = express();
const soajsMW = require('soajs.nodejs');

var url = require('url');

app.use(soajsMW({
serviceName : 'test'
}));

app.get('/tidbit/hello', function(req, res){
var url_parts = url.parse(req.url, true);
var query = url_parts.query;

var username = query.username;
var 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()
});
});

app.post('/tidbit/hello', function(req, res){
var response = req.soajs;

req.soajs.awareness.getHost(function(host){

response.controller = host;
res.send(response);
});
});

app.listen(4382);

Full Example on: https://github.com/soajs/soajs.nodejs.express

Hapi Example

'use strict';

const Hapi = require('hapi');
const soajsMW = require('soajs.nodejs')({serviceName : 'test'});
var url = require('url');

const server = new Hapi.Server();
server.connection({
    host: '0.0.0.0',
    port: 4380
});
server.ext({
    type: 'onRequest',
    method: function (request, reply) {
        soajsMW(request, reply, function (err){
            if (err) {
                throw err;
            }
            return reply.continue();
        });
    }
});
server.route({
    method: 'GET',
    path: '/tidbit/hello',
    handler: function (request, reply) {

	    var url_parts = url.parse(request.url, true);
	    var query = url_parts.query;

	    var username = query.username;
	    var lastname = query.lastname;

        return reply({
	        "message": "Hello, I am a HAPI service, you are ["+username+"] and your last name is : ["+lastname+"]"
        });
    }
});

server.route({
	method: 'POST',
	path: '/tidbit/hello',
	handler: function (request, reply) {
		var response = request.soajs;
		request.soajs.awareness.getHost(function(host){
			response.controller = host;
			return reply(response);
		});
	}
});

server.start((err) => {

    if (err) {
        throw err;
    }
    console.log('Server running at:', server.info.uri);
});

Full Example on: https://github.com/soajs/soajs.nodejs.hapi