Microsoft Visual Studio 2015 for every developer in every platform

Microsoft release the ultimate developer tool next version for preview. Now  you can download it from Microsoft Visual Studio downloads . It is designed for support n every developer platform.

 And Microsoft enables the access to developer platform for developers as open source project It is one of favorite thing to my self. hopefully it will rapidly improve the new feature additions to the visual studio.

in 12 Nov 2014 Microsoft announced their .NET 2015 version as well with Visual Studio 2015. All the core stacks of those platforms are now open source. Here is some summery form the MSDN release notes

• Over the coming months, we will be open sourcing the full server-side .NET Core stack, from ASP.NET 5 down to the Core Runtime and Framework, and the open source .NET will be expanded to run on Linux and Mac OS X in addition to Windows.
   
• A preview of the next generation of our tools is available today with Visual Studio 2015 Preview and .NET 2015 Preview.  Together, these bring industry-leading cross-platform mobile development tools, deep support for cloud development, and great productivity improvements across the breadth of the developer experience.
  
• Visual Studio Online is expanding its DevOps portfolio with the new Visual Studio Online Release Management service and Visual Studio Cloud Deployment Projects.

 With Visual studio 2015 developers can increase their focus on targeting the mobile device platform spanning iOS, Android and Windows, the need for cross-platform mobile development solutions has never been greater.

On top of great tools for building Universal Windows Applications, Visual Studio 2015 offers the most complete cross-platform mobile application development environment, with great solutions for C#, C++ and HTML/JavaScript development targeting iOS, Android, Windows and more.

Additionally It enables new rich emulators for android development that mostly smiler as windows Store app Emulators. It is very rich with Geo sensing , gestures etc. Now you don't need to vote on usual android bullshit emulator any more.

And Visual studio supports Apache Cordova and it enables to developers authoring, debugging, analyzing, packaging, and deploying HTML/ Javascript applications with Cordova in visual studio


Download ,  Enjoy and remember Contribute  To Visual Studio

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NodeJs web service With MongoDb

NodeJs is one of the powerful Lagrange that can do lot of things in programming world. When size of data become larger most of databases not can handle them efficiently. Therefor it leads to the change of database structure. Relational (SQL) database is not the best solution in most cases. NoSQL (Not Only SQL) databases are the best solution in those situations. One of the best NoSQL databse is MongoDb.

You can follow above hyperlinks to download and configure Nodejs and MongoDb within your local machine. if you having trouble  just comment below..ill update another post about configurations.

With this post I am going to demonstrate how to create REST service with NodeJs and MongoDB

You can use SublimeText as text editor for node js

1 . First create Document in MongoDb Name it and UserDetails

2. Add following Data to that document

/* 0 */
{
    "_id" : ObjectId("54608e50feeb4595a4f09651"),
    "userName" : "Harith",
    "Age" : 25,
    "Expired" : true
}
 
/* 1 */
{
    "_id" : ObjectId("54608ea4feeb4595a4f09652"),
    "userName" : "Jaliya",
    "password" : "123456",
    "Age" : 30
}
 
/* 2 */
{
    "_id" : ObjectId("5461d46dfeeb4595a4f09655"),
    "name" : "Joe Bookreader",
    "address" : {
        "street" : "123 Fake Street",
        "city" : "Faketon",
        "state" : "MA",
        "zip" : "12345"
    }
}
 
/* 3 */
{
    "_id" : ObjectId("54608f20feeb4595a4f09653"),
    "UserId" : "1",
    "address" : {
        "street" : "123 Fake Street",
        "city" : "Faketon",
        "state" : "MA",
        "zip" : "12345"
    }
}

Lets start to create NodeJs REST

First create Javascript file named it as Rest.js

To use MongoDb you need to install flowing npm package by this command
 npm install mongojs

Then add package.json file to the root of the folder and copy this to it

{
  "name": "Rest-server",
  "version": "0.0.1",
  "private": true,
  "dependencies": {
    "express": "3.3.4"
  }
}

Go to CMD and type npm install

Then start to coding real service in Rest,js

1. Import following libraries to the js file

var express = require('express');
var mongojs = require('mongojs');

2. Then create Array to store all data that comes from Mongo Database

var data = [];

3. Lets code REST Like this

// custom package
var app = express();
 
// Array definition to store data
var data = [];
 
// Http Normal get
app.get('/', function (req, res) {
    var db = require('mongojs').connect('mongodb://localhost:27017/DocumentOrDb');
    console.log("Server is in listen1");
    db.collection("UserDetails").find(function (err, docs) {

        data = [];
        docs.forEach(function (item) {
            data.push(item);
        })
    });
 
    console.log("Server end");
    res.send(data);
});

then run the service with cmd node Rest.js


Here is the full code

/*
  Rest Api with MongoDb Database 
  Author : prabathsl
  Copyright © prabathsl 2014
*/
 
// Libraries
var express = require('express');
var mongojs = require('mongojs');
 
// custom package
var app = express();
 
// Array definition to store data
var data = [];
 
// Http Normal get
app.get('/', function (req, res) {
    var db = require('mongojs').connect('mongodb://localhost:27017/DocumentOrDb');
    console.log("Server is in listen1");
    db.collection("SampleBigdata").find(function (err, docs) {
        data = [];
        docs.forEach(function (item) {
            data.push(item);
        })
    });
 
    console.log("Server end");
    res.send(data);
});

 Enjoy :) 

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Authentication with third party Auth providers in new era of Mobile Apps

When you are developing app, to increase security and manipulate users without taking user details is use authentication providers help such like Live, Google, Facebook, twitter , linked in, flickers etc.

With the newer versions of mobile BCL is not supported the olde way of authenticating with third party SDK's. All the BCL are updated with 8.1 and Universal apps.

With this post I'm gonna explain how to implement those authentication (ex: facebook)

1. you need to have facebook app. (http:\\developer.facebook.com)

To implement the Authentication you need to create separate class and interface that can handle Continuation events. Once authentication done it will redirect to the app using these Continuation objects.

Here is ContinuationManager Class that I used

using System.Text;
using Windows.ApplicationModel.Activation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
 
#if WINDOWS_PHONE_APP
    /// <summary>
    /// ContinuationManager is used to detect if the most recent activation was due
    /// to a continuation such as the FileOpenPicker or WebAuthenticationBroker
    /// </summary>
    public class ContinuationManager
    {
        IContinuationActivatedEventArgs args = null;
        bool handled = false;
        Guid id = Guid.Empty;
 
        /// <summary>
        /// Sets the ContinuationArgs for this instance. Using default Frame of current Window
        /// Should be called by the main activation handling code in App.xaml.cs
        /// </summary>
        /// <param name="args">The activation args</param>
        internal void Continue(IContinuationActivatedEventArgs args)
        {
            Continue(args, Window.Current.Content as Frame);
        }
 
        /// <summary>
        /// Sets the ContinuationArgs for this instance. Should be called by the main activation
        /// handling code in App.xaml.cs
        /// </summary>
        /// <param name="args">The activation args</param>
        /// <param name="rootFrame">The frame control that contains the current page</param>
        internal void Continue(IContinuationActivatedEventArgs args, Frame rootFrame)
        {
            if (args == null)
                throw new ArgumentNullException("args");
 
            if (this.args != null && !handled)
                throw new InvalidOperationException("Can't set args more than once");
 
            this.args = args;
            this.handled = false;
            this.id = Guid.NewGuid();
 
            if (rootFrame == null)
                return;
 
            switch (args.Kind)
            {
               
 
                case ActivationKind.WebAuthenticationBrokerContinuation:
                    var wabPage = rootFrame.Content as IWebAuthenticationContinuable;
                    if (wabPage != null)
                    {
                        wabPage.ContinueWebAuthentication(args as WebAuthenticationBrokerContinuationEventArgs);
                    }
                    break;
            }
        }
 
        /// <summary>
        /// Marks the contination data as 'stale', meaning that it is probably no longer of
        /// any use. Called when the app is suspended (to ensure future activations don't appear
        /// to be for the same continuation) and whenever the continuation data is retrieved 
        /// (so that it isn't retrieved on subsequent navigations)
        /// </summary>
        internal void MarkAsStale()
        {
            this.handled = true;
        }
 
        /// <summary>
        /// Retrieves the continuation args, if they have not already been retrieved, and 
        /// prevents further retrieval via this property (to avoid accidentla double-usage)
        /// </summary>
        public IContinuationActivatedEventArgs ContinuationArgs
        {
            get
            {
                if (handled)
                    return null;
                MarkAsStale();
                return args;
            }
        }
 
        /// <summary>
        /// Unique identifier for this particular continuation. Most useful for components that 
        /// retrieve the continuation data via <see cref="GetContinuationArgs"/> and need
        /// to perform their own replay check
        /// </summary>
        public Guid Id { get { return id; } }
 
        /// <summary>
        /// Retrieves the continuation args, optionally retrieving them even if they have already
        /// been retrieved
        /// </summary>
        /// <param name="includeStaleArgs">Set to true to return args even if they have previously been returned</param>
        /// <returns>The continuation args, or null if there aren't any</returns>
        public IContinuationActivatedEventArgs GetContinuationArgs(bool includeStaleArgs)
        {
            if (!includeStaleArgs && handled)
                return null;
            MarkAsStale();
            return args;
        }
    }
 
    /// <summary>
    /// Implement this interface if your page invokes the web authentication
    /// broker
    /// </summary>
    interface IWebAuthenticationContinuable
    {
        /// <summary>
        /// This method is invoked when the web authentication broker returns
        /// with the authentication result
        /// </summary>
        /// <param name="args">Activated event args object that contains returned authentication token</param>
        void ContinueWebAuthentication(WebAuthenticationBrokerContinuationEventArgs args);
    }

To handle the continuation after authentication you nee to modify your app.xaml.cs as well. Because Once you redirect to auth providers screen you are exit (deactivate) your app. then once auth provider redirect back your app gets activate .

Create object of ContinuationManager  in App.xml.cs

public static ContinuationManager continuationManager { get; private set; }

Then OnActivated event of the app add the continuation handle

protected async override void OnActivated(IActivatedEventArgs e)
{
   continuationManager = new ContinuationManager();

   //Check if this is a continuation 

   var continuationEventArgs = e as IContinuationActivatedEventArgs;
   if (continuationEventArgs != null)
   {
	continuationManager.Continue(continuationEventArgs);
   }
 
  Window.Current.Activate(); 

}

Then you are free to go with any kind of authentication that provide from auth provider 

    internal async Task FacebookLoginMethod()
        {
            String FacebookURL = "https://www.facebook.com/dialog/oauth?client_id=" + Uri.EscapeDataString("Your app Id") + "&redirect_uri=" + Uri.EscapeDataString("https://m.facebook.com/dialog/return/ms") + "&scope=read_stream&display=popup&response_type=token";
 
            System.Uri StartUri = new Uri(FacebookURL);

//To use windows phone or windows app with Fb authentication user this end uri and redirect uri. Both are working 

             System.Uri EndUri = new Uri("https://m.facebook.com/dialog/return/ms");
 
#if WINDOWS_PHONE_APP
            try
            {
                WebAuthenticationBroker.AuthenticateAndContinue(StartUri, EndUri, null, WebAuthenticationOptions.None);
            }
            catch
            {
 
            }
#endif
        }

and use this ContinueWeb authentication method inside the page that you call authentication. otherwise it will not working. Inherit the IWebAuthnticationContinuable interface to the page and add this method

public async void ContinueWebAuthentication(WebAuthenticationBrokerContinuationEventArgs args)
       {
           WebAuthenticationResult result = args.WebAuthenticationResult;
           if (result.ResponseStatus == WebAuthenticationStatus.Success)
           {
               token = await FilterToken(result.ResponseData.ToString());
 
           }
           else
           {
               MessageDialog Msg = new MessageDialog("Login failed");
               Msg.ShowAsync();
           }
 
       }

This WebAuthentication result wil contains the Authprovider's access token. Filterout it and do what ever graph is available with authentication provider. 


Enjoy ..

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HttpClient Caching

Is any one of you have an experience on when send http request through http client the response become the same (no change) even your source of the response (server) is updated.

It is the way that default http protocol behaves

By default HttpClient use a cache to store responses that come up with response headers without Cache-Control header. ( Ref: HTTP Header fields)

In a scenario you need to change the cache behavior with HttpClient you can have two options

1. Edit the service (server) to response with relevant cache headers
2. Modify your request headers

Edit the service (server) to response with relevant cache headers

In this model it give two benefits to you

• A content you will not use again is not stored in the client machine.
• Other requests can benefit from the cache (when using the same instance of HttpClient).

In your web service go to web.config file and in-side the system.serviceModel add following tag with relevant headers you need

     <client>
      <endpoint address="http://localhost/..." >
        <headers>
          <Cache-Control>no-cache</Cache-Control>
        </headers>
      </endpoint>
    </client>

Modify your request headers

if you don't have the access to the server you can go with this option. Just ad additional header with HttpClient and send the request then response automatically include these headers

HttpClient Client = new HttpClient();
Client.DefaultRequestHeaders.Add("Cache-Control", "no-cache");

Now your HttpClient is ready to handle http request with no cache .


here is Cache contol values that provide from W3 with Http headers.

    cache-directive = cache-request-directive
         | cache-response-directive

    cache-request-directive =
           "no-cache"                          
         | "no-store"                          
         | "max-age" "=" delta-seconds         
         | "max-stale" [ "=" delta-seconds ]   
         | "min-fresh" "=" delta-seconds       
         | "no-transform"                      
         | "only-if-cached"                    
         | cache-extension                     

     cache-response-directive =
           "public"                               
         | "private" [ "=" <"> 1#field-name <"> ] 
         | "no-cache" [ "=" <"> 1#field-name <"> ]
         | "no-store"                             
         | "no-transform"                         
         | "must-revalidate"                      
         | "proxy-revalidate"                     
         | "max-age" "=" delta-seconds            
         | "s-maxage" "=" delta-seconds           
         | cache-extension 

 Enjoy the code .. 

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Bug in Async BCL With Portable class libraries

Any of you try to use async framework inside the Portable Class Library (PCL)? Is it working ?
First instance it is not. There is a known bug in Async Framework with Poratable Class Libraries.
It will not detect the async and await correctly with task based operations

How to Fix
First install the BCL Nuget package to he your PCL (Microsoft.Bcl.Async)
in Console -




PM> Install-Package Microsoft.Bcl.Async

Then replace following tags with relevant replacement tag 

    <dependentAssembly>
        <assemblyIdentity name="System.Runtime" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.5.19.0" newVersion="2.5.19.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Threading.Tasks" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.5.19.0" newVersion="2.5.19.0" />
      </dependentAssembly>
    </assemblyBinding>

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Windows Azure Mobile Authentication Service

Magic with Azure mobile services is easy handling in Authentication for users. It allows you to authenticate users
1. Microsoft Account
2. Facebook Account
3. Twitter Account
4. Google Account
5. Azure Active Directory

What else developer need..

To enable all of those authentications you need to have apps running on those platforms. Url's for creating apps on each service provider is given below (Creating app on your hand *Get the developer manual help according to each technology)

1. Microsoft - https://account.live.com/developers/applications
2. Facebook - https://developers.facebook.com/ (Click on App's menu)
3. Twitter - https://apps.twitter.com/app/new
4. Google - https://console.developers.google.com/project

** In every instance that you create apps use your Azure Mobile Service Url 
HERE is URL for Microsoft Login

for json backend :https://<mobile_service>.azure-mobile.net/login/microsoftaccount
for .NET backend :https://todolist.azure-mobile.net/signin-microsoft

With later posts you can see how to use Azure Active directory

Start from the beginning

1. First login to your Azure portal and go to Mobile Services

2. Then select your Mobile Service , in here I have already created Mobile Service for the Azure Mobile Services post named as prabathblog. Select it and go inside. Then select IDENTITY  Tab from menu.

3. Fill the values according to the Login provider with details


4. Then go to the dashboard and download the app.

5. Use this code to authenticate in client side

        /// <summary>
        /// Simple authenticate
        /// </summary>
        /// <returns></returns>
        private async Task AuthenticateAsyncSimple()
        {
            while (user == null)
            {
                string message;
                try
                {
                    user = await App.MobileService
                        .LoginAsync(MobileServiceAuthenticationProvider.MicrosoftAccount);
                    message =
                        string.Format("You are now logged in - {0}", user.UserId);
                }
                catch (InvalidOperationException)
                {
                    message = "You must log in. Login Required";
                }
 
                var dialog = new MessageDialog(message);
                dialog.Commands.Add(new UICommand("OK"));
                await dialog.ShowAsync();
            }
        }

Enjoy your code

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Work with Async

Asynchronous Programming

If you are working with applications such as windows store and Windows Phone applications you may be found lot of functions that with Async keyword. Why Async?
We need async because when working with applications that interact with network (web, local network) , database, Files and reading hardware in the device are much more slower than the usual execution. Because of it communication bottlenecks are occur.

To avoid those communication bottlenecks async is born.

What Async Does ?
Async allows to run those delayed tasks in the background and meanwhile program can do what ever operations that does not depend on the awaited task.
simply,
"With Async Application can continue with other works that doesn’t depend on blocked resource until the blocked task finished"

Asynchronous programming available with .NET framework 4,5 onwards with Visual studio 2012. If you working on visual Studio 2012 without installing any of other libraries you can work on async

Concepts

Task
Task encapsulate all units of works in the async. Task contains following properties

• State : Running , Finished , Cancelled
• Result
• Thrown Exceptions

It will handle each and every exceptions and it throws all exceptions when task is finished.(await finished)


Important
If you really want to implement async methods and use them remember async and await keywords.

async keyword informs the compiler this method need to be handle separately by itself. Await keyword indicate the suspension of relative running async task.

When working with async,

• Use Async Suffix  | e.g. DownloadAsync
• Return Task or Task<T> according to situation
• void for only event handlers  

Example Wpf Code with simple async operation

public partial class MainWindow : Window

  {

      public MainWindow()

      {

          InitializeComponent();

      }

      private void btnNormal_Click(object sender, RoutedEventArgs e)

      {

          resultTxt.Text = getString("sample");

          independentWork();

      }

      private async void btnAsync_Click(object sender, RoutedEventArgs e)

      {

          resultTxt.Text = await getStringAsync();

      }

      /// <summary>

      /// Method with waiting in synchronize way

      /// ///

      /// </summary>

      /// <returns></returns>

      private string getString(string name)

      {

          //Task.Delay(2000);

          Thread.Sleep(2000);

          return "My String";

      }

      /// <summary>

      /// same method calling from async

      /// </summary>

      /// <returns></returns>

      private async Task<string> getStringAsync()

      {

          Task<string> asyncTask = Task.Factory.StartNew(() => getString("sample"));

          independentWork();

          return await asyncTask;

      }

      

      /// <summary>

      /// this work is independent from others

      /// </summary>

      private void independentWork()

      {

          resultTxt.Text += "\n independent work is done ";

      }

  }

Download Sample Code Here

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Improve Performance of the Application

As and software producer all of us want to do is software product with correct functionality. Is that enough ? No. We need to give product with correct functionality with optimum resource consumption as well.

Today I'm going to tell you some tips and trikes about resource optimization. basically it is about Memory and CPU resources.

1. Switch for multiple If
 When you are using multiple If conditions ( Most of the time more than 2 ) CPU (Registry level) instructions check as far as use much If with code. It consume more registers in CPU. But with switch it just use check and Jump CPU instruction that far more faster than assignments. Using jump tables makes switches much faster than some if-statements

Use switch when ever possible once you find more than two if statements.

2. Use structures according to the situation
Execution of class is much more consume resources than class.  Whenever you don't need to use functions bind with objects and when you don't go with boxing and unboxing much with code.

3. Chunky calls
Don't let your functions to handle lot of task by itself. use modularity to avoid it.

4. Add Collections
Never try to assign collection items one by one to the another collection. Just try to use simple casting and try to add entire collection directly.

5. Working with strings.
When you are working with string most of the cases we try to concatenate string by '+'operator.(including me ). But sad story is there is more optimal solution than that. use string bulider to concatenate strings.

Here for start.

6. Use bits whenever as possible.
I saw most of the programmers use integers/strings to hold the simple states, flags. Please don't do that there is more than 2 states. Just use bit or bool to store states. It will optimize code and resource as well. ( Simply bit is smaller than more bits)

7. Array as possible
When we use simple basic array it will helpful to maintain machine instructions(registry). Other collections need more than array because most of them are derived form it. Array is basic element in modern machine instructions.

8. ObservableCollection vs List
Use List whenever that your items not binded with the UI. Observation collections are derived from List and it also holds the property changed notifications. If there is no use of property change go for List.  ObservableCollection check the property change when it on use and because of that it consume more.

9. For than foreach
Use while, for and do while loops wherever than foreah. foreach has good performance but basic loops are better than it.

10. ToString
Some  programmers use ToString method wherever elements are already strings. Use ToString wherever the element that con the string. don't use ToString as habit. With integers use
ToStringLookup will optimize memory heap that using with converting integer.

11. Don't sort collections already sorted.
Check collection already sorted or not before sort it.

12. Global variables.
Use global variables when you using same type of object frequently

13. Constant and static
Constants are not assignable memories but they are easy to load.

Static is more faster than instant creations. When load statics no need of run time to check the instance



Hope this is helps...

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Starts with MVVM

With the growth of programming and application development  there are major requrement that emerged the design patterns. Such as MVP(Model View Presentation) and MVC (Model View Controller) are common design patterns that allows developer to isolate codes. Bu the advanced features of XAML such as data biding, data templates, commands and on demand interaction between application and logic's guide world to MVVM (Model View ViewModel)

MVVM basically derived from the MVC design pattern. It clearly  create separation between these MVVM layers more than MVC.














Model contains all abstraction of data  not any logic's behind data. View is contains XAML views still not the logics. Importance is Model and view are not directly inter action with each other.


ViewModel Contains all  business logic's and data bind properties such as Collections. And it will interact with the View and Model. It takes notifications from model and send them to View as well as other way around.

Ex: If new item added to collection in view It automatically notify and update the View without any interaction.

Study Simple MVVM code here










Full Code In Media Fire 
http://bit.ly/MvvMDemo