Category Archives: javascript

Easy Web Application Development for Beginners with Node-RED (2)

Objective

In this tutorial I will create a Node-RED server application that will process a request from a client web form. The server will save the request data in a NoSQL database.

Requirements

You must have:

  • Access to a Bluemix account.

1. Create a Node-RED Starter Application

Start to create a Node-RED Starter server application. A client application sends a form request to the Node-RED server, the server processes the form data and sends a response back to the client.

Node-RED is a so-called visual workflow editor, which lets you create an application workflow by dragging and dropping visual nodes onto an editor.
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Creating a Nodejs App with Watson AlchemyAPI and CloudantDB

WIP

Requirements:

Overview:

  1. Setup
  2. Setup Details
  3. Add Watson AlchemyAPI
  4. Add Cloudant DB

Setup

  1. Login to Bluemix, in a separate tab login to Github,
  2. In Bluemix open Catalog->Boilerplates and create a ‘Node.js Cloudant DB Web Starter’ Boilerplate, named ‘<username>-nodejs-app1’, click CREATE
  3. Go to ‘Overview’, scroll down to ‘Continuous delivery’ and click ‘Enable’
  4. In the ‘Toolchain Settings’, change the name of the Toolchain to ‘<username>-nodejs-app1’, and click Create,
  5. If the Github THINK or CODE icon displays a configuration error, from the block’s dropdown icon in the topright, click the ‘Configure’ link to correct the configuration of your Github account,
  6. Go to your Github account and make sure that the repository for the new Bluemix app is created successfully,
  7. Copy the Git URL, on localhost open a commandline terminal, change to your development directory and clone the new repository,
    cd ~/dev/src/bluemix
    git clone https://github.com/remkohdev/remkohdev-nodejs-app1.git
    cd remkohdev-nodejs-app1
  8. Open the project directory in your favorite editor,
  9. Open the ‘package.json’ file and change the ‘name’ property to ‘<username>-nodejs-app1’,
  10. From the commandline, in your project directory,
    git status
    git add .
    commit -m "change package.json name property"

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Learning JavaScript 101 (wad-js-01)

JavaScript

Introduction

  1. Java and JavaScript?
  2. ECMAScript ES6
  3. V8 Engine
  4. The JavaScript Ecosystem
    • Browser and HTML
    • Server Side: Node.js
    • Mobile

QAVideos (3) – Extending the Data Model and Using Open API Initiative (OAI) in Node.js

(updated: 20170319) WIP
This is part 3 in a series to build a sample application called QAVideos using API Connect. QAVideos is a Question and Answer application that uses videos instead of text. Think of QAVideos as StackOverflow meets Youtube. QAVideos will use LoopBack, API Connect, Open API Initiative (OAI formerly Swagger.io), OpenWhisk, Object Storage.

  • In part 1 ‘QAVideos (Part 1), Adding User Management to Node.js’, I added User Management to a Node.js app using API Connect.
  • In part 2 ‘QAVideos (Part 2), Adding a Custom Model and ORM in Node.js‘, I added a custom data model, i.e. a Video model, and used ORM to persist the model to a PostgreSQL database.
  • In part 3 ‘QAVideos (Part 3), Extend Model and Using Open API Initiative (OAI) in Node.js‘, I extend the built-in User model with a Member, add a Question and Answer based on the Video model, and add a Sticker, while using the Open API Specification to define and manage the application and APIs.
  • In next parts, the idea is to add other possibly features: deploy the OAI definition file to Bluemix via API Connect, add Object Storage for Video support, create an Ionic/Apache Cordova based mobile client, add an automated build, deployment and test script, add a Content Delivery Network (CDN) to the backend, add event-driven OpenWhisk APIs, containerize the application, add chat, and possibly more.

Prerequisites

  • Node, npm, and API Connect must be installed,
  • Check if the ‘apic’ tool is installed, by running ‘apic -v’ from the commandline. If not installed, follow the installation instructions, here.
  • Get the source code from part 2 of this tutorial.
  • Install the ‘npm’ dependencies,
    npm install
  • Configure the file ‘~/server/datasources.json’,
  • Test if QAVideos (part 2) is running correctly by typing ‘apic start’ in the root directory, open a browser and go to ‘http://0.0.0.0:4001’ in your browser.

Table of Content

  1. The OAI Definition File
  2. Create the Extended Data Model

Open API Initiative (OAI, based on Swagger)

The OAI is based on Swagger.io, an API Framework. The OAI is an open API definition standard. Frameworks like API Connect use the OAI definition file to generate the server, client, data model and documentation.

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QAVideos (2) – Add Custom Model and ORM to Node.js

(updated: 20170318)
This is part 2 in a series to build QAVideos. QAVideos is a Question and Answer application that uses videos instead of text. Think of QAVideos as StackOverflow meets Youtube. QAVideos will use LoopBack, API Connect, Open API Initiative (OAI formerly Swagger.io), OpenWhisk, Object Storage.

In part 1 ‘QAVideos (Part 1), Adding User Management to Node.js with API Connect‘, I showed how to add User Management to a Node.js app using API Connect.
In this part 2, I will add a custom data model, i.e. a Video model and use ORM to persist data to a PostGreSQL database.
Part 3 (to be updated) is found here, which adds model extensions and uses Open API Initiative (formerly Swagger) support.

Source code for QAVideos is released per part via https://github.com/remkohdev/qavideos/releases.

Requirements

  • Install Node.js and npm,
  • Install API Connect.
  • Check if the ‘apic’ tool is installed, by running ‘apic -v’ from the commandline. If not installed, follow the installation instructions, here.
  • Get the source code for part 1 of this tutorial and follow the installation instructions for QAVideos Release v1.0.0. First clone the repository, then make sure you fetch all the remote tags to your local repository, and then checkout the v1.0.0 tag.
    git clone https://github.com/remkohdev/qavideos.git
    git fetch --all --tags --prune
    git checkout tags/v1.0.0

Table of Contents

  1. Create Data Model
  2. Define Relation
  3. Adding ACL
  4. Add Video Functionality
  5. Add Data Source

1. Create Data Model

First, test if QAVideos (part 1) is running correctly. Open a commandline, change your directory to the root directory of your QAVideos application, type ‘apic start’, and browse to ‘http://0.0.0.0:4001‘ in your browser.

Now, I want to add a custom model ‘Video’ so that users can manage their list of videos. To do this, I create a model for the Video with the ‘apic’ tool, and define the relationship between Video and User (a User can own many videos), and specify the access level of Users to Video objects using an Access Control List (ACL).
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QAVideos (1) – Adding User Management to Node.js

(updated: 2017-03-14)
QAVideos is a Question and Answer application that uses videos instead of text. Think of QAVideos as StackOverflow meets Youtube. QAVideos will use LoopBack, API Connect, Open API Initiative (OAI formerly Swagger.io), OpenWhisk, Object Storage.

Requirements:

  1. QAVideos (1) – Adding User Management to Node.js. Part 1 creates the ‘StrongLoop’ application with built-in User and Role management with authentication, with an API layer based on Open API Initiative (OAI), formerly Swagger.io, and I add an Angular.js based web UI.
  2. QAVideos (2) – Add Custom Model and ORM to Node.js. Part 2 adds custom object models and ORM to a PostGreSQL database.
  3. QAVideos (3) – Extend Model and Using Swagger.io in Node.js. Part 3 adds object model extensions and takes a closer look at Open API Initiative (OAI) support.

Steps:

  1. Application Design
  2. Create the Application
  3. Add Static Pages
  4. Add Angular
  5. Add Signup
  6. Create an Authentication Service Provider
  7. Add Login
  8. Add Logout

1. Application Design

The initial design of the QAVideos application is very simple. A user can register, login and logout. An authenticated user can create, update and delete videos to the platform and see a list of their videos. Unauthenticated users can see all videos.

About StrongLoop

If you are not familiar with IBM API Connect (formerly StrongLoop), it is an API platform for Node.js and includes Loopback to quicly compose and manage APIs, and use graphical tools like the API Connect Designer to create, edit, manage and deploy your APIs. I will use the Loopback library that is part of API Connect to compose the model and the APIs.

You must install the API Connect cli for this tutorial. Test to see if you have API Connect cli installed:
$ apic -v
API Connect: v5.0.6.2 (apiconnect: v2.5.21)

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How to create a MEAN+ stack application (MongoDB, Express, Angular, Node + Bootstrap, Jade)

Steps

      Create a Node.js with Express.js App
      Create a Git repository and clone to localhost
      Add Angular.js
      Add Bootstrap
      Add MongoDb
      Add Jade
      Add an API for GET /people
      Connect to MongoDb
      Create a sortable table with Angular

Create a Node.js with Express.js App

I will be using Bluemix to host, build and deploy my Node.js application and the MongoDb service. I am developing on my localhost for unit testing before I upload my application to Bluemix, but you can also use the online editor and online Git instead.

1. If you do not have a Bluemix account yet, sign up for a free account at http://ibm.biz/bluemixnyc,
2. Once you have an account, go to your Bluemix console at https://console.ng.bluemix.net/,
3. Go to your Dashboard,
4. In the ‘Cloud Foundry Apps’ box, click ‘CREATE APP’,

5. Choose ‘WEB’

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[JavaScript] Find Related Concepts as D3js Bubble Chart

The Find Related Concepts API from IDOL OnDemand returns the most relevant terms and concepts from related documents. Here’s represented as a D3 Bubble Chart. Thanks to incredibly good work by Mike Bostock. For a description of the API go here https://www.idolondemand.com/developer/apis/findrelatedconcepts#overview
For D3 Data-Driven Documents go here: http://d3js.org

[JavaScript] POST upload file with XHR FormData

This example uses the Optical Character Recognition (OCR) API from IDOL OnDemand. For details see here: https://www.idolondemand.com/developer/apis/ocrdocument#overview

HTML5 and JavaScript: Flip an Image using HTML5 Canvas

See the working code example on jsfiddle.


<!DOCTYPE html>
<html>
<head>
<title>Flipping an Image Horizontally and Vertically</title>
<script src="jquery-1.11.1.min.js"></script>
<script type="text/javascript">
var imageurl = null;
//
$(document).ready( function() {
$('#loadimage').click(function() {
urlProvided();
});
$('#mirrorh').click(function() {
mirror(1,0);
});
$('#mirrorv').click(function() {
mirror(0,1);
});
});
//
function urlProvided() {
var userinput = document.getElementById('imageurl');
imageurl = userinput.value;
loadImage();
}
function loadImage(){
//
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
//
var img = new Image();
img.src = imageurl;
img.onload = function(){
ctx.drawImage(img,0,0);
};
//
var w = img.width;
var h = img.height;
canvas.width = w;
canvas.height = h;
}
//
function mirror(mirrorh,mirrorv){
//
var canvas=document.getElementById('canvas');
var ctx=canvas.getContext('2d');
//
var img = new Image();
img.src = imageurl;
//
ctx.clearRect(0,0,canvas.width,canvas.height);
ctx.save();
//
var w = img.width;
var h = img.height;
if(mirrorh){
ctx.scale(1, -1);
ctx.translate(0, -h);
}
if(mirrorv){
ctx.scale(-1, 1);
ctx.translate(-w,0);
}
ctx.drawImage(img,0,0,img.width,img.height,null,null,w,h);
ctx.save();
}
</script>
</head>
<body>
<div>
Your image URL: <input type="text" id="imageurl"></input><button id="loadimage">load image</button>
</div>
<div>
<button id="mirrorh">mirrorh</button>
<button id="mirrorv">mirrorv</button>
</div>
<div>
<canvas id="canvas"></canvas>
</div>
</body>
</html>