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.

Monday, 31 October 2016

Change Password Form In Angular 2

Angular 2 doesnt having validation for checking two fields having equal values, for that we need to create custom validation.
Lets create a change password form to demonstrate the custom validation for matching new password and confirm new password.
<div class="row">
    <div class="col-md-offset-3 col-md-6">
        <div class="panel panel-default">
            <div class="panel-body">
                <h2 class="text-center">Change Password</h2>
                <form [formGroup]="changePasswordForm" (ngSubmit)="changePassword(changePasswordForm.value)">
                    <div class="form-group" [ngClass]="{'has-error':!changePasswordForm.controls['old_password'].valid && changePasswordForm.controls['old_password'].touched}">
                        <label for="old_password">Old Password</label>
                        <input type="password" name="old_password" class="form-control" id="oldPassword" placeholder="Old Password" [formControl]="changePasswordForm.controls['old_password']" />
                        <small *ngIf="changePasswordForm.controls['old_password'].hasError('required') && changePasswordForm.controls['old_password'].touched" class="text-danger">Old Password Required</small>
                    </div>
                    <div class="form-group" [ngClass]="{'has-error':!changePasswordForm.controls['new_password'].valid && changePasswordForm.controls['new_password'].touched}">
                        <label for="new_password">New Password</label>
                        <input type="password" name="new_password" class="form-control" id="newPassword" placeholder="New Password" [formControl]="changePasswordForm.controls['new_password']" />
                        <small *ngIf="changePasswordForm.controls['new_password'].hasError('required') && changePasswordForm.controls['new_password'].touched" class="text-danger">New Password Required</small>
                    </div>
                    <div class="form-group" [ngClass]="{'has-error':!changePasswordForm.controls['confirm_new_password'].valid && changePasswordForm.controls['confirm_new_password'].touched}">
                        <label for="confirm_new_password">Confirm New Password</label>
                        <input type="password" name="confirm_new_password" class="form-control" id="newPassword" placeholder="Confirm New Password" [formControl]="changePasswordForm.controls['confirm_new_password']" />
                        <small *ngIf="changePasswordForm.controls['confirm_new_password'].hasError('required') && changePasswordForm.controls['c:onfirm_new_password'].touched" class="text-danger">Confirm New Required</small>
                        <small *ngIf="changePasswordForm.controls['confirm_new_password'].hasError('passwordMatch') && changePasswordForm.controls['confirm_new_password'].touched" class="text-danger">Password mismatch</small>
                    </div>
                    <div class="form-group text-center">
                        <button type="submit" class="btn btn-default" [disabled]="!changePasswordForm.valid">Change Password</button>
                    </div>
                </form>
            </div>
        </div>
    </div>
</div>
Now, lets create a ts component for this
    import { Component } from '@angular/core';
    import { FormGroup, FormBuilder, FormControl, Validators, AbstractControl } from '@angular/forms';
    
    @Component({
      selector: 'change-password',
      templateUrl:'change-password.component.html',
      providers: [ UserService ]
    })
    
    export class ChangePasswordComponent {
    
        changePasswordForm:FormGroup;

        constructor(fb: FormBuilder){
            this.changePasswordForm = fb.group({
                'old_password': [null, Validators.required],
                'new_password': [null, Validators.required],
                'confirm_new_password': [null, [Validators.required, this.passwordMatch]] 
            });
        }
    
        passwordMatch(control: AbstractControl){
            let paswd = control.root.get('new_password');
            if(paswd && control.value != paswd.value){
             return {
                 passwordMatch: false
             };   
            }
            return null;
        }
    
        changePassword(value){
            if(this.changePasswordForm.valid){
                console.log("Change password form valid");
            }
        }
    
    }
    
Thats it, now register this component in the app module and use the selector <change-password></change-password> to see the change password form

Simple Login Form With Validation in Angular 2

Angular 2 having the form builder to build the login form with the validation, Here we see a simple login form with the validation.
Lets first create a html component with the user name and password form
<div class="row">
    <div class="col-md-offset-4 col-md-4">
        <div class="panel panel-default">
            <div class="panel-body">
                <h2 class="text-center text-muted">Login</h2>
                <form [formGroup]="loginForm" (ngSubmit)="login(loginForm.value)">
                    <div class="form-group" [ngClass]="{'has-error':!loginForm.controls['user_name'].valid && loginForm.controls['user_name'].touched}">
                        <label for="username">User Name</label>
                        <input type="text" name="user_name" class="form-control" id="username" placeholder="User Name" [formControl]="loginForm.controls['user_name']" />
                        <small *ngIf="loginForm.controls['user_name'].hasError('required') && loginForm.controls['user_name'].touched" class="text-danger">Username Required</small>
                    </div>
                    <div class="form-group" [ngClass]="{'has-error':!loginForm.controls['password'].valid && loginForm.controls['password'].touched}">
                        <label for="password">Password</label>
                        <input type="password" name="username" class="form-control" id="password" placeholder="Password" [formControl]="loginForm.controls['password']" />
                        <small *ngIf="loginForm.controls['password'].hasError('required') && loginForm.controls['password'].touched" class="text-danger">Password Required</small>
                    </div>
                    <div class="form-group text-center">
                        <button type="submit" class="btn btn-default" [disabled]="!loginForm.valid">Login</button>
                    </div>
                </form>
            </div>
        </div>
    </div>
</div>
The html component is created, now lets create the ts component for this form.
import { Component } from '@angular/core';
import { FormGroup, FormBuilder, Validators } from '@angular/forms';

@Component({
  selector: 'login-section',
  templateUrl:'login.component.html'
})

export class LoginComponent {
    loginForm: FormGroup;

    constructor(fb: FormBuilder){
        this.loginForm = fb.group({
            'user_name': [null, Validators.required],
            'password': [null, Validators.required]
        });
    }


    login(value){
        if(this.loginForm.valid){
           console.log("Login form valid");
        }        
    }
    
 }
Thats it, we have created the login form with validation, now register this component in the app.module and use the selector <login-section></login-section> to see the login form.