Tuesday 28 November 2017

On Demand Image Resizing With AWS

Delivering the image according to the device and resolution is always a big challenge. If you want to convert the image dynamically based on the resolution without using any expensive service provider like cloudinary, here is the solution for you which uses the Amazon resources.

AWS offers a simple solution that automatically deploys and configures a serverless architecture that is optimized for dynamic image manipulation. The diagram below presents the Serverless Image Handler architecture you can deploy in minutes using the solution's implementation guide and accompanying AWS CloudFormation template.


  • Amazon CloudFront provides a caching layer to reduce the cost of image processing.
  • Amazon API Gateway provides API endpoint powered by AWS Lambda functions to dynamically make image modifications.
  • AWS Lambda retrieves the image from the existing Amazon Simple Storage Service (Amazon S3) bucket and uses Thumbor to return a modified version of the image to the API Gateway.
  • The API Gateway returns the new image to CloudFront for delivery to end-users.

To implement this solution simply click on this link

The On demand image manipulation is done by the Thumbor service and it offers lots of filters, to see full list of available options click on this link

Finally you can resize the image with the url like http://cloudfront…/500x500/path/image01.jpg

You can apply filters like http://cloudfront…/filters:blur(80)/path/image01.jpg

You can combine both the resize and filters.

Refference: http://docs.aws.amazon.com/solutions/latest/serverless-image-handler/deployment.html

Thursday 2 March 2017

Bundling Angular 2 systemjs application for production

To deploy the angular 2 application for production, we must bundle it to make the application to run faster. Here are the steps for bundling the application using systemjs builder and gulp task

Include the following in the devDependencies of package.json file
"devDependencies":{
    ...
    "gulp": "^3.9.1",
    "gulp-clean": "^0.3.2",
    "gulp-html-replace": "^1.6.1",
    "gulp-shell": "^0.5.2",
    "lite-server": "^2.2.2",
    "run-sequence": "^1.2.2",
    "systemjs-builder": "^0.15.31",
}
Create vendor.ts file inside the app folder with the following contents
import 'core-js-shim';
import 'zone';
import 'reflect';
Include these libraries in the map section of systemjs.config.js to bundle it
 map: {
    ...
    'text': 'plugin-text.js',
    
    //shims
    'core-js-shim':'npm:core-js/client/shim.min.js',
    'zone':'npm:zone.js/dist/zone.js',
    'reflect':'npm:reflect-metadata/Reflect.js'
}
Create plugin-text.js with the following contents to bundle the html files
exports.translate = function(load) {
    if (this.builder && this.transpiler) {
        load.metadata.format = 'esm';
        return 'exp' + 'ort var __useDefault = true; exp' + 'ort default ' + JSON.stringify(load.source) + ';';
    }

    load.metadata.format = 'amd';
    return 'def' + 'ine(function() {\nreturn ' + JSON.stringify(load.source) + ';\n});';
}

Create a gulpfile.js file with the following contents to bundle the dependencies
var gulp = require('gulp');
var shell = require('gulp-shell');
var clean = require('gulp-clean');
var htmlreplace = require('gulp-html-replace');
var runSequence = require('run-sequence');
var Builder = require('systemjs-builder');
var builder = new Builder('', 'systemjs.config.js');

var bundleHash = new Date().getTime();
var mainBundleName = bundleHash + '.main.bundle.js';
var vendorBundleName = bundleHash + '.vendor.bundle.js';

// This is main task for production use
gulp.task('dist', function(done) {
    runSequence('clean', 'compile_ts', 'bundle', function() {
        done();
    });
});

gulp.task('bundle', ['bundle:vendor', 'bundle:app'], function () {
    return gulp.src('index.html')
        .pipe(htmlreplace({
            'app': mainBundleName,
            'vendor': vendorBundleName
        }))
        .pipe(gulp.dest('./dist'));
});

gulp.task('bundle:vendor', function () {
    return builder
        .buildStatic('app/vendor.js', './dist/' + vendorBundleName)
        .catch(function (err) {
            console.log('Vendor bundle error');
            console.log(err);
        });
});

gulp.task('bundle:app', function () {
    return builder
        .buildStatic('app/main.js', './dist/' + mainBundleName)
        .catch(function (err) {
            console.log('App bundle error');
            console.log(err);
        });
});

gulp.task('compile_ts', ['clean:ts'], shell.task([
    'tsc'
]));

gulp.task('clean', ['clean:ts', 'clean:dist']);

gulp.task('clean:dist', function () {
    return gulp.src(['./dist'], {read: false})
        .pipe(clean());
});

gulp.task('clean:ts', function () {
    return gulp.src(['./app/**/*.js', './app/**/*.js.map'], {read: false})
        .pipe(clean());
});
Finally include the generated js in the index.html file, the index.html may look like
<!DOCTYPE html>
<html>
  <head>
    <title>Angular 2 QuickStart</title>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="styles.css">
  </head>
  <body>
    <my-app>Loading...</my-app>
    <script src="dist/1474222768447.vendor.bundle.js"></script>
    <script src="dist/1474222768447.main.bundle.js"></script>
  </body>
</html>

Friday 20 January 2017

Datepicker In Angular 2

To use the datepicker in the angular 2 application use ng2-bootstrap
include ng2-bootstrap and moment in your package.json and hit npm install to install both in the node_modules
include datepicker module in your module file. The app.module.ts file will be,
import { NgModule }      from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { DatepickerModule } from 'ng2-bootstrap/ng2-bootstrap';
import { RouterModule } from '@angular/router';
import { AppComponent } from './app.component';
import { DatepickerComponent } from './datepicker.component';

@NgModule({
  imports:      [ BrowserModule, DatepickerModule],
  declarations: [ AppComponent, DatepickerComponent ],
  bootstrap:    [ AppComponent ]
})

export class AppModule { }
    
Create the text box in html and write the functionality in the ts file like
<div class="container">
    <div class="col-md-6">
        <label for="datepicker" class="text-primary">Date Picker</label>
        <div class="input-group date-picker">
            <input type="text" class="form-control" name="datpicker" id="datpicker" placeholder="Date Picker" [(ngModel)]="datePickerValue" (focus)="showDatePicker()" readonly>
            <span class="input-group-addon" (focus)="showDatePicker()"><span class="glyphicon glyphicon-calendar" aria-hidden="true"></span></span>
        </div>
        <div class="dp-popup" *ngIf="isDatePickerShown">
            <datepicker [(ngModel)]="datePickerDate" [showWeeks]="false" [maxDate]="today" [ngModelOptions]="{standalone: true}" (selectionDone)="dateSelected($event)"></datepicker>
        </div>   
    </div>
</div>
    
import { Component, OnInit, ViewChild } from '@angular/core';
import { DatepickerModule } from 'ng2-bootstrap/ng2-bootstrap';
import * as moment from 'moment';

@Component({
    selector: 'datepicker-component',
    templateUrl: 'datepicker.component.html',
    host: {
        '(document:click)': 'handleClick($event)'
    },
})

export class DatepickerComponent {
    
    isDatePickerShown:boolean = false;
    datePickerDate;
    datePickerValue;
    today:Date = new Date();

    constructor() {
        
    }

    showDatePicker(){
         this.isDatePickerShown = true;
     }

     hideDatePicker(){
         this.isDatePickerShown = false;
     }

     dateSelected(event){
         this.datePickerValue = moment(event).format("YYYY-MM-DD");
         this.hideDatePicker();
     }

     handleClick(event){
         if(!(event.target.closest('datepicker') != null || event.target.closest('.btn') != null || event.target.closest('.date-picke') != null)){
             this.hideDatePicker();
         }
     }

}
    

Bootstrap Modal in Angular 2

To use the bootstrap modal in the angular 2 application use ng2-bootstrap
include ng2-bootstrap and moment in your package.json and hit npm install to install both in the node_modules
include modal module in your module file. The app.module.ts file will be,
import { NgModule }      from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { ModalModule } from 'ng2-bootstrap/ng2-bootstrap';
import { RouterModule } from '@angular/router';
import { AppComponent } from './app.component';
import { BootstrapModalComponent } from './bootstrap-modal.component';

@NgModule({
  imports:      [ BrowserModule, ModalModule],
  declarations: [ AppComponent, BootstrapModalComponent ],
  bootstrap:    [ AppComponent ]
})

export class AppModule { }
    
Write the bootstrap modal in html and write the functionality in the ts file like
<div class="container">
        <button type="button" class="btn btn-default" (click)="showModal()">Open</button>
    </div>
    <div bsModal #bootstrapModal="bs-modal" class="modal fade" tabindex="-1" role="dialog" aria-labelledby="bootstrapModal"
    aria-hidden="true">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" aria-label="Close" (click)="closeModal()">
                    <span aria-hidden="true">&times;</span>
                </button>
                <h4 class="modal-title">Bootstrap modal</h4>
            </div>
            <div class="modal-body">
                <p>This is bootstrap modal</p>
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-default" (click)="closeModal()">Close</button>
            </div>
        </div>
    </div>
</div>
    
import { Component, OnInit, ViewChild } from '@angular/core';
import { ModalDirective } from 'ng2-bootstrap/ng2-bootstrap';

@Component({
    selector: 'bootstrap-modal',
    templateUrl: 'bootstrap-modal.component.html'
})

export class BootstrapModalComponent {
    
    @ViewChild('bootstrapModal') public bootstrapModal:ModalDirective;

    constructor() {        
    }

    showModal(){
        this.bootstrapModal.show();
    }

    closeModal(){
        this.bootstrapModal.hide();
    }

}
    

Thursday 19 January 2017

Using forge-js in angular 2 for calculating sha256

To use forge-js in angular 2 application for using cryptographic function like sha clone the repository from the git and build the files and include the forge.all.js file in your index.html file
Since the forge-js is not written in typescript and not having the d.ts file. We have to declare the forge and use the functions inside that.
To calculate the sha256 enter the code like.
declare var forge:any;

export class Common{
    getSha256String(value){
      var md = forge.md.sha256.create();
      md.update(value);
      return md.digest().toHex();
    },
}
Now simply call the method getSha256String with the value to get the encrypted value.