Introducing Node.js in an Oracle technology environment (including hands-on)

Lucas Jellema, 31st March 2016
Introducing Node.js
1

Overview
• Get used to it: JavaScript on the Server
• First steps with Node.js and yes: hello world!
• Some language essentials: functions (and closures)
• Modules and npm
• The Single Thread or: the quest for scalability
• Handling HTTP requests
– static file serving
– serving rich client web applications [such as Oracle JET]
– Implementing REST APIs and mBaaS (and iPaaS)
• Making HTTP calls to external APIs and Services
• Database interaction from Node.js

3
Supporting Resources on GitHub
• https://github.com/lucasjellema/sig-nodejs-amis-2016

7
JavaScript
in enterprise architecture
Mobile
Client
Browser
Web Tier
Static file
serving
REST
APIs
DBBusiness Tier
Integration
Orchestration
/ BPM
Background
Jobs
ERP
SaaS
External
Service
External
Service

8
Node.js is like a JS-DK –
JavaScript Virtual Machine
Custom
Node.js
app
Custom
Node.js
app Custom
Node.js
app
machine code

9
Brief History of Node.js
• 2009 – unveiled by Ryan Dahl, written on Linux, leveraging Google V8
• 2010
– Initial release of express – the default web application server framework
• 2011
– package manager npm introduced – to publish and share open-source Node.js libraries
and simplify installation, updating and uninstallation of libraries
– Native Windows implementation of Node.js released
• 2011-2015 Many Cloud Platforms supporting Node.js
– Heroku, Joyent, Cloud Foundry, Nodester, NodeJitsu, Microsoft Azure, IBM BlueMix,
Google AppEngine, AWS, …
• 2015
– Oracle releases node-oracledb Database Driver for Node.js
– Various forks brought back together: Node v4.0 including V8 with ES6 features
– Open Source under Governance by the Node.js Foundation under Linux Foundation
– Support for ARM processors
• 2016
– Oracle Application Container Cloud with native support for Node.js applications
– Current release: 5.9.1 (22nd March)

Storage
Compute
DBaaS
Storage
Compute
DBaaS
JCS
SOA
CS
Storage
Compute
ACC
ICS
MCS
DCS
PCS
Compute
ACC
IoT
CS
OSN Sites
CS
mediator-proxy

11
Node.js one of the viable platforms within
new Oracle Micro Services platform

12
Hello World
// my first Node.js program
console.log("Hello World!");

13
Hello World – using a function
function greeting() {
console.log("Hello World!");
}
greeting();

14
Hello World – read
commandline arguments
function greeting(greetedPerson) {
console.log("Hello "+ greetedPerson + "!");
}
// assume command line: node hello-world-3.js someName
var greetee = process.argv[2];
greeting(greetee);

15
Hello World – pass around a
function reference
var g = function greeting(greetedPerson) {
}
g(greetee);

16
Hello World – have one function
execute [a reference to ] another
var g = function greeting(greetedPerson) {
}
function reception( greetFunction, greetee) {
greetFunction(greetee); // execute the passed in function
}
reception(g, greetee);

17
Hello World – callback functions
and time outs – no state yet
// callback functions used with timeout
var g = function (greetedPerson) {
}
var r = function ( greetFunction, greetee) {
greetFunction(greetee);
}
for (var i=2;i<process.argv.length;i++) {
setTimeout( r(g, process.argv[i]), i*1500);
}
console.log('The Main Program Flow is Done!');

18
Hello World – closures with state
executed on time out
}
function getGreeter ( greetee, greetFunction) {
var toGreet = greetee;
console.log('I will greet '+ greetee + ' in a little while');
return function () { greetFunction(toGreet)}; // the closure
}
for (var i=2;i<process.argv.length;i++) {
setTimeout( getGreeter( process.argv[i], g), i*1500);
}
console.log('The Main Program Flow is Done!');

19
Modules
• Node programs can be organized in modules
• A module is file that exports a scope that may contain (public) functions
and shared objects
• Modules are ‘imported’ through the require function
– Add a line such as var localRef = require(‘moduleName’); in a file to get access at
runtime to all the goodies from the module
• Node ships with a set of core modules that can be required into any
program – without additional installation or configuration; for example:
– fs: file system operations
– path: string transformations around file system operations
– os: access to some operating systems details
– util: utility functions, for example util.log to log messages to console with timestamp
– http: for HTTP protocol based network operations

20
File manipulation from Node.js
- using core module fs
//write a file with all command line arguments on separate lines
var fs = require('fs')
, util = require('util');
process.argv.slice(2).forEach(function (val) {
fs.appendFileSync("./output.txt", val + "n");
});
util.log('The Main Program Flow is Done!');

21
Hello World –
using core module util
var util = require('util');
util.log(util.format('Hello %s!', greetedPerson));
}
function getGreeter ( greetee, greetFunction) {
var toGreet = greetee;
util.log( util.format('I will greet %s in a little while', toGreet));
return function () { greetFunction(toGreet)};
}
process.argv.slice(2).forEach(function (val, index, array) {
setTimeout( getGreeter(val, g), index*1500);
});
util.log('The Main Program Flow is Done!');

22
Packages
• A package is a bundle of resources that supports development of a node
application
– Design time (test, code analyze, format, browserify, package, …)
– Run time
• A package can contain one or more modules that may or may not be
intended to be ‘required’ into a node application
• Packages are [downloaded and] added to the source folders of a node
application
• Package management can be tricky
– An application can depend on multiple packages
– Packages can depend on multiple [versions of] packages themselves
– Gathering and keeping up to date all compatible versions of all required packages is
potentially complex, time consuming and error prone
– Enter: npm
• and package.json – the closest thing to a pom-file

23
Reusing node modules
• “So that's what npm is. It's a way to reuse code from other developers,
and also a way to share your code with them, and it makes it easy to
manage the different versions of code.”
• www.npmjs.org

24
npm
• Bring in a package to your current application
– npm install <package name>
The package is downloaded and installed in folder node_modules
• Create a new application with a neat description
– npm init
This will create a package.json file that
describes the [Node.js] application and its dependencies
• Use
– npm install <package name> --save
To have dependencies on the package added to the package,json file
– npm install
To have all packages listed in package.json installed or updated into the
node_modules folder

25
Node.js can handle incoming
HTTP requests
• Similar to a Java Servlet or PHP page, a Node.js application can contain
logic to interpret and respond to an HTTP request
Browser
Web Tier
Static file
serving
REST
APIs
http request
Any other
HTTP
client

26
Core Modules for (inbound & outbound)
networking: http, https, net, dgram
• No separate installation required (included with core Node.js)
• Handle incoming request and/or make outbound request
• Handle URL (path, query parameters, post payload or Form encoding or
file upload)
• Handle headers, encoding, compression, …
Web Tier
http(s) request http(s) request

27
Simplest form of HTTP handling
// invoke from browser or using curl: curl http://127.0.0.1:3000
var http = require('http');
var server = http.createServer(function handleRequest(req, res) {
res.write('Hello World!');
res.end();
}).listen(3000);
console.log('server running on port 3000');
Web Tierhttp(s) request

28
Interpret request and respond
appropriately
// invoke: curl http://127.0.0.1:3000/do/me/a/resource?name=Lex
var http = require('http')
, url = require('url') ;
console.log('URL '+ req.url);
var queryObject = url.parse(req.url,true).query;
var name = queryObject.name;
console.log('path: '+url.parse(req.url).pathname);
console.log('queryObject: '+JSON.stringify(queryObject));
res.write('Hello '+ name + '!');
res.end();
}).listen(3000);

29
Interpret request and respond
appropriately
// invoke: curl http://127.0.0.1:3000/do/me/a/resource?name=Lex
, url = require('url') ;
console.log('URL '+ req.url);
var queryObject = url.parse(req.url,true).query;
var name = queryObject.name;
console.log('path: '+url.parse(req.url).pathname);
console.log('queryObject: '+JSON.stringify(queryObject));
res.write('Hello '+ name + '!');
res.end();
}).listen(3000);

30
Static File Serving
// serve static file: /public/index.html
, fs= require('fs');
res.writeHead(200, { 'content-type': 'text/html' });
fs.createReadStream('./public/index.html').pipe(res);
}).listen(3000);
Local file
system
index.html

31
Remote Resource Serving –
http in and http out
var http = require('http');
var options = {
host: 'www.un.org', path: '/en/universal-declaration-human-rights/' };
res.writeHead(200, { 'content-type': 'text/html' });
http.get(options, function handleRemoteResponse(resp) {
var body="";
resp.on("data", function(chunk) { //response returned in chunks
body = body+chunk;
});
resp.on("end", function() { //when response is complete, pass it on
res.end(body);
});
}).on('error', function(e) {
console.log("Got error: "+ e.message);
});
}).listen(3000); Remote
Website
http
request

32
Express web application
framework
• Fast, unopinionated, minimalist web framework for Node.js
• Framework on top of core Node.js top facilitate incoming HTTP requests
– “Express provides a thin layer of fundamental web application features, without
obscuring Node.js features that you know and love.”
• Convenient for
– Web Server for static files
– API implementation (REST)
– Any incoming HTTP request handling
• Express is distributed as npm package
– npm install express

33
Express - Simplest form of HTTP
handling
var express = require('express')
, http = require('http');
var app = express()
.use(function (req, res, next) {
res.end('Hello World!');
});
// Create HTTP server with Express app as the request listener
http.createServer(app)
.listen(3000);

34
Express – Even simpler form of HTTP
handling (or at least simpler code)
var express = require('express');
express().use(function (req, res, next) {
res.end('Hello World!');
}).listen(3000);

35
Static File Serving
// static file server for all resources in public and below
// will server public/index.html when invoked at http://127.0.0.1:3000
var express = require('express'); //npm install express
express().use(express.static(__dirname + '/public'))
.listen(3000);
Integration
Tierhttp(s) request
Local file
system
index.html
image.jpg
some-pdf.pdf

36
Oracle JET on Node.js
• Oracle JET is a rich client web application
• All the action is on the client
• Role of Node.js: serve the JET application with all its required resources
– All static HTML, CSS and JS files
app
.js

37
Oracle JET on Node.js
• Oracle JET is a rich client web application
• All the action is on the client
• Role of Node.js: serve the JET application with all its required resources
– All static HTML, CSS and JS files
• Additionally: Node.js can provide back end APIs and proxy that JET
application leverages
REST
API
app
.js

38
Handling Form Submit and other
HTTP POST requests
// static file server for all resources in public and below
// AND handle forms submission to path /forms/...
var express = require('express'); //npm install express
var bodyParser = require('body-parser'); // npm install body-parser
var app = express()
.use(bodyParser.urlencoded({ extended: true}))
.post('/forms/*', function (req, res) { //process
console.log(JSON.stringify(req.body));
res.end('Thank you '+ req.body.firstname
+' '+req.body.lastname);
})
.use(express.static(__dirname + '/public'))
.listen(3000);
Integration
Tier
POST request Local
file
system

39
Handling REST GET requests
var express = require('express'), fs = require('fs');
var departments= JSON.parse(fs.readFileSync('departments.json', 'utf8'));
var app = express()
.get('/departments/:departmentId', function (req, res) {
var department = getDepartment(req.params['departmentId']);
console.log(JSON.stringify(department));
res.send( department);
})
.get('/departments', function (req, res) {
res.send( departments);
})
.use(express.static(__dirname + '/public'))
.listen(3000);
function getDepartment(depIdentifier) {
for (var i=0; i< departments.length; i++) {
if (departments[i].DEPARTMENT_ID == deptIdentifier) {
return departments[i];
}//if
}//for
}// getDepartment
Integration
Tier
GET request
Local file
system
departments
.json

40
Handling REST GET & Form
POST requests
var express = require('express'),bodyParser = require('body-parser')
, fs = require('fs');
var app = express()
.use(bodyParser.urlencoded({ extended: true}))
.post('/forms/department', function (req, res) { //process
console.log(JSON.stringify(req.body));
departments.push( {"DEPARTMENT_ID":req.body.departmentId
,"DEPARTMENT_NAME":req.body.departmentName});
res.end('Thank you for the new department '+
req.body.departmentId+" "+req.body.departmentName);
})
.get('/departments/:departmentId', function (req, res) {
…
.listen(3000);
Integration
Tier
GET request
Local file
system
departments
.json
Form Submit

41
Serve Department details –
retrieved from external REST API
var express = require('express'),bodyParser = require('body-parser')
, fs = require('fs'), https = require('https');
var app = express()
.get('/departmentdetails/:departmentId', function (req, res) {
var departmentId = req.params['departmentId'];
var department = getDepartment(departmentId);
// get employee details for department from remote API
https.get({ host: 'data-api-oraclecloud.com', port: 443,
path: '/departments/'+departmentId, method: 'GET'
}, function handleRemoteResponse(resp) {
var body="";
resp.on("data", function(chunk) {body += chunk; });
resp.on("end", function() {
department.employees = JSON.parse(body);
res.send(department); });
});
})
.listen(3000);
Integration
Tier
GET request
Local file
system
departments
.json
REST
API

43
Access speed for data
retrieved from various sources
Source: Beginning Node.js - by Basarat Ali Syed Apress, released: December 2014

44
Threads in web application
handling HTTP-requests

45
Ready-to-run Threads in web
application handling HTTP-requests

46
cash
registers
desk to collect
large pieces
Warehouse
Exit
waiting area
shopping area
Only a single desk to handle all
customers who want to have stuff
from the warehouse brought to them
– compare with over a dozen cash
registers

47
Single Thread model in Node.js

48
Single Thread
• No synchronous calls or blocking waits are done on the thread
– intensive work too is pushed to another process
• After the question is asked, the thread moves
• When a response arrives – as an asynchronous event – the callback
function is given the opportuniy to act on it
– Again, as quickly as possible, not tying up shared resources!

50
The single thread way: Nginx

51
The single thread way: Nginx

52
Asynchronously assembling
the HTTP response
• Receive HTTP request
– Possibly leverage cookie to re-establish state/context
• Set work in motion to collect data (remote API call, DB call) and register
callback – with original request scope
• Stop processing, vanish, release resources
• When callback is invoked, use response to construct the response
– Complete and send the response
Callback == Closure
(function to execute with
context to execute in)

53
Artist API
• Provide rich JSON message for an artist
• External APIs invoked: Spotify and Echonest
• External calls are made in parallel
– Waiting is done in parallel
– Constructing the response is done when both responses are in
Integration
Tier
GET request
for some artist

54
async
• The node module async is a utility module which provides straight-
forward, powerful functions for working with asynchronous JavaScript.
• Available for server side Node.js and for use in the browser client
• Program easily with asynchronous interactions
– Coordinate parallel or sequential calls and deal with errors
• Example operations:
– Map
– Reduce
– Filter
– Waterfall
– Parallel
– ForEachOf
– Series

55
async – execute in parallel
var async = require(‘async')
, fs = require(‘fs');
var obj = {dev: "/dev.json", test: "/test.json", prod: "/prod.json"};
var configs = {};
async.forEachOf(obj, function (value, key, callback) {
fs.readFile(__dirname + value, "utf8", function (err, data) {
if (err) return callback(err);
try {
configs[key] = JSON.parse(data);
} catch (e) {
return callback(e);
}
callback();
});
}, function (err) { // when all parallel actions are done – do something
if (err) { console.error(err.message); return;}
// configs is now a map of JSON data
doSomethingWith(configs);
})
For each property
in the object…
… execute this
function
Asynchronously
read the file .. and when done,
call this function
Notify forEachOf of the
completion of this branch
When all parallel branches under
forEachOf are done, do this function

56
node-oracledb database driver
• The node-oracledb driver connects to Oracle Database
for fast and functional applications. It is an open source
project with Apache 2.0 license.
• It is maintained as an NPM package by Oracle and is under active
development.
• https://github.com/oracle/node-oracledb or
npm install node-oracledb
• Note: the Oracle Application Container Cloud preloads this driver to any
instance of a Node.js container – ready to connect to DBaaS or on
premises database
• Support for SQL and PL/SQL, Transaction Management, CLOBs and
BLOBs, Ref Cursors, Types and Collections, authentication, …
– Leveraging OCI Oracle (Fat) Client Libraries

57
Connect to Oracle Database
from node application …
var oracledb = require('oracledb');
var dbConfig = require('./dbconfig.js');
oracledb.getConnection(
{
user : dbConfig.user,
password : dbConfig.password,
connectString : dbConfig.connectString
},
function(err, connection)
{
if (err) {
console.error(err.message);
return;
}
connection.execute(
...
Integration
Tier

58
… and perform SQL or PL/SQL
...
connection.execute(
"SELECT department_id, department_name " +
"FROM departments " +
"WHERE department_id = :did",
[180],
function(err, result)
{
if (err) {
console.error(err.message);
doRelease(connection);
return;
}
console.log(result.metaData);
console.log(result.rows);
doRelease(connection);
});
});
function doRelease(connection)
{ connection.release( function(err) {…});}
Integration
Tier

59
Oracle Application Container Cloud
for Node.js with DB driver
Application Container Cloud
Docker
Node.js ContainerREST clients
data-api
RES
T
API
DBaaS
Service
Binding
oracledb
DB driver
MyJCSDB
demos PDB1
H
R

60
Next steps and beyond
• API Development
• Explore npm packages – 10Ks of them
– For SOAP, XML, IMDB, Dictionary, Geography, Text-to-Speech, Loopback mBaaS …
• Advanced topics: Web Sockets , security, scaling, H/A, state in a stateless
world, queuing and scheduling ‘background jobs’
• Creating your own modules and NPM packages
– Contribute to existing packages
• Promises – for an escape from callback hell
• IDEs – Visual Studio Code, WebStorm, NetBeans
• Debugging
• Testing
• Deployment
• Rethink mBaaS & iPaaS

Introducing Node.js in an Oracle technology environment (including hands-on)

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