Facing connection issues with Gitlab repositories!!

There are two ways to connect with Gitlab

using HTTP and SSH

this guide will let you know about the SSH way and the whole guide is targeting windows os. So what are we waiting for? 

Generate an SSH key pair

for ED25519:

ssh-keygen -t ed25519 -C "<comment>"

For 2048-bit RSA:

ssh-keygen -t rsa -b 2048 -C "<comment>"

Follow the instruction and set the passcode and all

After successful execution, SSH key will be generated under c:\users\<username>\.ssh

Add an SSH key to your GitLab account

Run this command in Git Bash:

cat ~/.ssh/id_ed25519.pub

1. Replace id_ed25519.pub with your filename. For example, use id_rsa.pub for RSA.

2. Sign in to GitLab.
3. On the top bar, in the top right corner, select your avatar.
4. Select Preferences.
5. On the left sidebar, select SSH Keys.
6. In the Key box, paste the contents of your public key. If you manually copied the key, make sure you copy the entire key, which starts with ssh-ed25519 or ssh-rsa, and may end with a comment.
7. In the Title box, type a description, like any string will serve the purpose.
8. Optional. In the Expires at the box, select an expiration date. In:
   • GitLab 13.12 and earlier, the expiration date is informational only. It doesn’t prevent you from using the key. Administrators can view expiration dates and use them for guidance when deleting keys.
   • GitLab 14.0 and later, the expiration date is enforced. Administrators can allow expired keys to be used.
   • GitLab checks all SSH keys at 02:00 AM UTC every day. It emails an expiration notice for all SSH keys that expire on the current date. 
   • GitLab checks all SSH keys at 01:00 AM UTC every day. It emails an expiration notice for all SSH keys that are scheduled to expire seven days from now. 
9. Select Add key

Verify that you can connect

open the terminal or PowerShell and run the command

ssh -T git@gitlab.example.com (for private gitlab)

ssh -T git@gitlab.com

In the final step, open the Visual Studio and try to clone the repository using an ssh URL.

hope this will work for you! If not, please let me know in the comments.

Unzipping inside GDrive

To extract a zip file in google drive itself, we can use google colab to extract zip files inside google drive:

1. Open Google Colaboratory
2. Mount Google Drive on Colab

3. from google.colab import drive

4. drive.mount('/gdrive')

5. Add autherize code in colab to access gdrive

6. unzip file like this

!unzip '/gdrive/My Drive/[filename].zip' 

          -d '/gdrive/My Drive/Destination/'

Introduction To IoT And Supported Devices

During DevCon16 @ Chandigarh, I found lots of people showing interest in this topic. So, I decided to write some basic articles on the same.

I will try to cover the following topics in the series of articles:

1. IoT development boards available in the market.
2. Different types of operating system installations.
3. Basic Home automation.

IoT stands for Internet of Things. Here, Things mean variety of devices, such as temperature and humidity sensor, heart rate monitoring sensor, and PIR sensor etc. Some consider Things to be a mixture of hardware, software, and data.

IoT is a network between different kinds of hardware (or we can say sensors), and software, so that they can share and exchange data. Some of very common examples  of IoT are Google Thermostat, Phillips Hue, Fitness bands (fitbit, Microsoft band etc).

IoT development boards available in market

 There are lots of IoT development boards available in the market, currently. Some of them are:

1. Raspberry Pi (The most popular among developers because of the community and support)
2. Bannana Pi
3. Intel Galileo
4. Ardunio Uno
5. And, lots of leading manufacturers are providing their own development boards

Lots of new development boards are making their space in the market but Raspberry Pi is one of the most famous boards available in the market. The reason behind its popularity is the community behind this development board. You can easily find online support if you are ever stuck somewhere.

“Raspberry Pi is a credit-card sized computer that plugs into your TV and a keyboard. It is a capable little computer which can be used in electronics projects, and for many of the things that your desktop PC does, like spreadsheets, word processing, browsing the internet, and playing games. It also plays high-definition video. We want to see it being used by kids all over the world to learn programming.”

Raspberry Pi is available in different models, such as Raspberry Pi 2 Model B, Raspberry Pi 3 Model B, Raspberry Zero and the Pi 1 Model B+ and A+.

Raspberry Pi 2 and Raspberry Pi 3 are the latest models currently available. Raspberry Pi Zero is officially launched only in the UK and the US.

Raspberry Pi 2 and Raspberry Pi 3 both are almost the same in looks but internally,  some upgrades have been done in the latest model. Both of the models are loaded with 1 GB RAM. The older model contains quad-core 900 MHz processor while Pi 3 is powered with quad-core 1.2 GHz. Pi 2 runs on 32-bit architecture whereas Pi 3 runs on 64-bit architecture.


                                          

                                         

You can power up your Pi with an ordinary mobile charger having a micro-usb cable. There are three ways to connect your video device: HDMI, AV (RCA cable) or display port available on the board. There is an official 7” touch display available for this purpose.

The main attraction of IoT development boards is GPIO pins. GPIO means General Purpose Input Output pin or interface.

                                           

Each pin holds a special purpose, like some pins output +5v, +3.3v, Ground (GND), or 26 GPIO pins.

By using these pins, we can read and write the data from different sensors. By using these pins, without using extra circuits, we can connect to up to 26 sensors. But somehow, if we need to connect more devices, then we have on board support for I2C.

Operating System supportThe major difference between a microcontroller and these IoT development boards is the support for variety of Operating Systems. For example: Raspberry Pi 2 and Pi 3 support various flavors of Linux and Windows 10 IoT Core.

Different flavors of Linux are Jessie Raspbain (based on debian Linux), Ubuntu Mate, Snappy Ubuntu core, Kodi (xmbc) media player operating system. To install the Operating System, Pi supports SD-Card.

Problem downloading file having spaces in Firefox

The problem is while having spaces in the file name and trying to download file in Firefox using ASP.NET web site.

Response.AddHeader("Content-Disposition", "attachment; filename=" + Filename);


The solution to this problem is to use following code

Response.AddHeader("Content-Disposition", "attachment; filename=\"" + Filename + "\"");

Error while powering on internal error vmware player

Today I faced a issue while using VMware player, I was trying to access my newly created vm but when I was trying to run it, it was giving me an error:

"Error while powering on internal error"

I tried lot of troubleshooting like creating new vm, re-creation of vm, reinstallation of VMware player. But nothing worked.

Then I found a KB on VMware site, the VMware Authorization Service is not running.

To check if service is running or not:

1. You should be a member of Administrator group.
2. Click Start and then type Run.
3. Type services.msc and click OK.
4. Locate the VMware Authorization service.
5. Click Start the service.

So if this service is not running please run it, it will solve your problem.

Ref: VMware KB

Observer pattern

To describe the Observer pattern, lets take an example of Football game.

The specific design problem is,

When the position of a ball changes, all the players should be notified straight away. 

Define a one-to-many dependency between objects so that one object changes state, all its dependents are notified and updated automatically.

Subject (Interface) exposes us three methods Attach, detach and notify. 

ConcreteSubject is football. Which exposes the current position to observers.

Observer (interface) exposes the update method.

ConcreteObserver is player. Which implements update method and with in this method it calls for the position of the ball and set the observerstate to the same.

ref: applying design pattern

Sharepoint 2013 Installation on windows 2012 R2

As sharepoint 2013 first service pack has been released so there is no need to follow these steps but if you don't want to download 1.03 GB data (size of the Service pack 1). You can follow following steps to run SHAREPOINT 2013 on your Windows server 2012 R2.


1. Login to your R2 server as Administrator. Start Power Shell as Administrator and execute following statements:

Import-Module ServerManager

Add-WindowsFeature NET-WCF-HTTP-Activation45,NET-WCF-TCP-Activation45,NET-WCF-Pipe-Activation45 -Source D:\Sources\sxs

Add-WindowsFeature Net-Framework-Features,Web-Server,Web-WebServer,Web-Common-Http,Web-Static-Content,Web-Default-Doc,Web-Dir-Browsing,Web-Http-Errors,Web-App-Dev,Web-Asp-Net,Web-Net-Ext,Web-ISAPI-Ext,Web-ISAPI-Filter,Web-Health,Web-Http-Logging,Web-Log-Libraries,Web-Request-Monitor,Web-Http-Tracing,Web-Security,Web-Basic-Auth,Web-Windows-Auth,Web-Filtering,Web-Digest-Auth,Web-Performance,Web-Stat-Compression,Web-Dyn-Compression,Web-Mgmt-Tools,Web-Mgmt-Console,Web-Mgmt-Compat,Web-Metabase,Application-Server,AS-Web-Support,AS-TCP-Port-Sharing,AS-WAS-Support, AS-HTTP-Activation,AS-TCP-Activation,AS-Named-Pipes,AS-Net-Framework,WAS,WAS-Process-Model,WAS-NET-Environment,WAS-Config-APIs,Web-Lgcy-Scripting,Windows-Identity-Foundation,Server-Media-Foundation,Xps-Viewer -Source D:\Sources\sxs

D:\ is your windows installation path.

2. Download all prerequisites from the Internet and save it on local disk of the server, e.g. C:\SP2013Prereq:
SQL Server 2008 R2 SP1 Native Client
Microsoft WCF Data Services 5.0
Microsoft Information Protection and Control Client (MSIPC)
Microsoft Sync Framework Runtime v1.0 SP1 (x64)
Windows Identity Extensions
Windows Identity Foundation (KB974405)
Windows Server AppFabric
CU 1 for AppFabric 1.1 (KB2671763)

3. Install all prerequisites directly from the prerequisites folder in the download sequence, except the last two (AppFabric and CU 1 for AppFabric).
4. AppFabric requires special configuration, therefore installing it usual way is not be enough for SharePoint. Install it using following statement from command line

WindowsServerAppFabricSetup_x64.exe /i CacheClient","CachingService","CacheAdmin /gac

6. Restart your server

Congratulations! Now you will be able to start SharePoint 2013 installer directly and to continue with SharePoint 2013 installation and configuration.
 

Difference between Events and Delegates

Events are basically actions raised by an object when some condition met.
Like In stock class there is a property named Limit, and it raised an notification when it reaches certain limit. This notification is done by events


Delegate is more generic term which is similar to a pointer to a function.
They are generally used as a input parameter. In particular they are perfect way to implement Strategy pattern. For example, if I want to sort a List of objects, I can provide a Compare strategy to the method to tell the implementation how to compare two objects.

Stamping an image with text and Image

public static void AddWaterMark(MemoryStream ms, string watermarkText, MemoryStream outputStream)
        {
            System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
            Graphics gr = Graphics.FromImage(img);
            Font font = new Font("Tahoma", (float)40);
            Color color = Color.FromArgb(50, 241, 235, 105);
            double tangent = (double)img.Height / (double)img.Width;
            double angle = Math.Atan(tangent) * (180 / Math.PI);
            double halfHypotenuse = Math.Sqrt((img.Height * img.Height) + (img.Width * img.Width)) / 2;
            double sin, cos, opp1, adj1, opp2, adj2;

            for (int i = 100; i > 0; i--)
            {
                font = new Font("Tahoma", i, FontStyle.Bold);
                SizeF sizef = gr.MeasureString(watermarkText, font, int.MaxValue);

                sin = Math.Sin(angle * (Math.PI / 180));
                cos = Math.Cos(angle * (Math.PI / 180));
                opp1 = sin * sizef.Width;
                adj1 = cos * sizef.Height;
                opp2 = sin * sizef.Height;
                adj2 = cos * sizef.Width;

                if (opp1 + adj1 < img.Height && opp2 + adj2 < img.Width)
                    break;
                //
            }

            StringFormat stringFormat = new StringFormat();
            stringFormat.Alignment = StringAlignment.Center;
            stringFormat.LineAlignment = StringAlignment.Center;

            gr.SmoothingMode = SmoothingMode.AntiAlias;
            gr.RotateTransform((float)angle);
            gr.DrawString(watermarkText, font, new SolidBrush(color), new Point((int)halfHypotenuse, 0), stringFormat);

            img.Save(outputStream, ImageFormat.Jpeg);
        }


in the same place where you call gr.DrawString, you can also do gr.DrawImage(position, size, overlayImage). It helps if your image-to-overlay is loaded from a PNG file (with transparency) to produce the best quality.


One of the best way to stamp an image with time and location. 
Ref of the above example is from http://stackoverflow.com/questions/1224653/place-watermark-image-on-other-images-c-asp-net

Strategy Pattern

To describe the strategy pattern, lets take an example of Football game.
The specific design problem is,
       when game is in progress any team can change its strategy from defend to attack or vice-          
       versa.

The solution for the same is strategy pattern.
         We need to let the algorithm vary independently from clients that uses it.
Very soon I will update article with sample code and class diagram.

Login failed for user 'IIS APPPOOL\ASP.NET v4.0'

To solve this problem we need to change the application pool's identity. 

You can change the ApplicationPoolIdentity from IIS7 -> Application Pools -> Advanced Settings.

Under ApplicationPoolIdentity you will find local system. This will make your application run under NT AUTHORITY\SYSTEM, which is an existing login for the database by default.

Devart oracle issue: ORA-01482

By default, strings in EF Code-First are considered as unicode and without explicit length. They would be VARCHAR2 if the [not unicode string] and [length < 4000 symbols] settings were specified in mapping for a particular property.

Solution for the attribute mapping. Specify the MaxLength(123) attribute if you have the VARCHAR2(123) column in your database. Also turn off PropertyMaxLengthConvention from the Conventions collection in DbModelBuilder (this convention is used for unicode strings).

Solution for the smooth mapping is just Set HasMaxLength(123) and IsUnicode(false) for the corresponding property. In this case there is no need to turn off PropertyMaxLengthConvention.

And we have to disable auto proxy generation if we are using EF Code-First approch. This can be done by writing
Configuration.ProxyCreationEnabled = false;
in the constructor of the Context class.


Ref: http://forums.devart.com

UML Basic notations

UML is popular for its diagrammatic notations. We all know that UML is for visualizing, specifying, constructing and documenting the components of software and non software systems. Here theVisualization is the most important part which needs to be understood and remembered by heart.

Structural Things:

Graphical notations used in structural things are the most widely used in UML. These are considered as the nouns of UML models. Following are the list of structural things.

• Classes
• Interface
• Collaboration
• Use case
• Active classes
• Components
• Nodes

Class Notation:

UML class is represented by the diagram shown below. The diagram is divided into four parts.

• The top section is used to name the class.
• The second one is used to show the attributes of the class.
• The third section is used to describe the operations performed by the class.
• The fourth section is optional to show any additional components.

Classes are used to represent objects. Objects can be anything having properties and responsibility.

Object Notation:

The object is represented in the same way as the class. The only difference is the name which is underlined as shown below.

As object is the actual implementation of a class which is known as the instance of a class. So it has the same usage as the class.

Interface Notation:

Interface is represented by a circle as shown below. It has a name which is generally written below the circle.

Interface is used to describe functionality without implementation. Interface is the just like a template where you define different functions not the implementation. When a class implements the interface it also implements the functionality as per the requirement.

Collaboration Notation:

Collaboration is represented by a dotted eclipse as shown below. It has a name written inside the eclipse.

Collaboration represents responsibilities. Generally responsibilities are in a group.

Use case Notation:

Use case is represented as an eclipse with a name inside it. It may contain additional responsibilities.

Use case is used to capture high level functionalities of a system.

Actor Notation:

An actor can be defined as some internal or external entity that interacts with the system.

Actor is used in a use case diagram to describe the internal or external entities.

Initial State Notation:

Initial state is defined to show the start of a process. This notation is used in almost all diagrams.

The usage of Initial State Notation is to show the starting point of a process.

Final State Notation:

Final state is used to show the end of a process. This notation is also used in almost all diagrams to describe the end.

The usage of Final State Notation is to show the termination point of a process.

Active class Notation:

Active class looks similar to a class with a solid border. Active class is generally used to describe concurrent behaviour of a system.

Active class is used to represent concurrency in a system.

Component Notation:

A component in UML is shown as below with a name inside. Additional elements can be added wherever required.

Component is used to represent any part of a system for which UML diagrams are made.

Node Notation:

A node in UML is represented by a square box as shown below with a name. A node represents a physical component of the system.

Node is used to represent physical part of a system like server, network etc.

Behavioural Things:

Dynamic parts are one of the most important elements in UML. UML has a set of powerful features to represent the dynamic part of software and non software systems. These features include interactions and state machines.

Interactions can be of two types:

• Sequential (Represented by sequence diagram)
• Collaborative (Represented by collaboration diagram)

Interaction Notation:

Interaction is basically message exchange between two UML components. The following diagram represents different notations used in an interaction.

Interaction is used to represent communication among the components of a system.

Grouping Things:

Organizing the UML models are one of the most important aspects of the design. In UML there is only one element available for grouping and that is package.

Package Notation:

Package notation is shown below and this is used to wrap the components of a system.

Annotational Things:

In any diagram explanation of different elements and their functionalities are very important. So UML has notes notation to support this requirement.

Note Notation:

This notation is shown below and they are used to provide necessary information of a system.

Relationships

A model is not complete unless the relationships between elements are described properly. TheRelationship gives a proper meaning to an UML model. Following are the different types of relationships available in UML.

• Dependency
• Association
• Generalization
• Extensibility

Dependency Notation:

Dependency is an important aspect in UML elements. It describes the dependent elements and the direction of dependency.

Dependency is represented by a dotted arrow as shown below. The arrow head represents the independent element and the other end the dependent element.

Dependency is used to represent dependency between two elements of a system.

Association Notation:

Association describes how the elements in an UML diagram are associated. In simple word it describes how many elements are taking part in an interaction.

Association is represented by a dotted line with (without) arrows on both sides. The two ends represent two associated elements as shown below. The multiplicity is also mentioned at the ends (1, * etc) to show how many objects are associated.

Association is used to represent the relationship between two elements of a system.

Generalization Notation:

Generalization describes the inheritance relationship of the object oriented world. It is parent and child relationship.

Generalization is represented by an arrow with hollow arrow head as shown below. One end represents the parent element and the other end child element.

Generalization is used to describe parent-child relationship of two elements of a system.

Extensibility Notation:

All the languages (programming or modeling) have some mechanism to extend its capabilities like syntax, semantics etc. UML is also having the following mechanisms to provide extensibility features.

• Stereotypes (Represents new elements)
• Tagged values (Represents new attributes)
• Constraints (Represents the boundaries)

Extensibility notations are used to enhance the power of the language. It is basically additional elements used to represent some extra behaviour of the system. These extra behaviours are not covered by the standard available notations.

More details are found here

I found this information here, a great blog to follow

Finally relaxation from Custom paging logics

Finally Sql server 2012 CTP 1 has the power to handle paging.
A new feature named Ad-hoc Query Paging is introduced in new version of Sql Server.

SQL paging using ORDER BY OFFSET n ROWS and FETCH NEXT n ROWS ONLY


In previous versions of Microsoft SQL Server, like SQL Server 2005, SQL Server 2008, or in SQL Server 2008 R2 t-sql ORDER By clause was used to sort the returned result set from the SELECT part of the query.
The following sql query is an example to how Order By clause was used before SQL Server 2012 CTP 1, Denali version.

-- Return all rows from Person table sorted by BusinessEntityID
SELECT ID, FirstName, LastName
FROM Person.Person
ORDER BY ID




It will return all records from the table




T-SQL Paging in SQL Server 2012 with ORDER BY OFFSET n ROWS FETCH NEXT n ROWS ONLY

Now here is OFFSET in Order By clause, this is a new t-sql feature in SQL Server 2012 CTP 1.
If Offset is used in an ORDER BY clause the result set will ignore the first offset amount rows and will not return back to the client. But the rest will be included in the result set.

-- Return all rows except the first 10 rows
SELECT ID, FirstName, LastName
FROM Person.Person
ORDER BY ID
OFFSET 10 ROWS




The above t-sql Select statement returns all rows (Total Rows - 10). This is how OFFSET 10 ROWS works in ORDER BY clause







Now an other improvement in ORDER BY clause is FETCH NEXT 10 ROWS ONLY syntax.
This new feature enables sql developers to fetch only specified amount of rows in the returned result set of the sql Select statement.
Let's say if you are doing paging with 10 rows in every page, then use Fetch Next 10 Rows Only

-- Return 10 rows after skipping the first 10 rows
SELECT ID, FirstName, LastName
FROM Person.Person
ORDER BY ID
OFFSET 10 ROWS
FETCH NEXT 10 ROWS ONLY




Please note that Fetch Next n Rows Only cannot be used without Offset n Rows hint in Order By clause.
Otherwise new Microsoft SQL Server 2012 sql engine will throw the following error :
Msg 153, Level 15, State 2, Line 5
Invalid usage of the option NEXT in the FETCH statement.

SQL Paging with Variables used in ORDER BY OFFSET n ROWS FETCH NEXT n ROWS ONLY

Let's now use sql parameters for creating a more flexible t-sql paging select statement in SQL Server 2012, Denali databases.

DECLARE @PageNumber int = 3 -- 3th page
DECLARE @RowsCountPerPage int = 15 -- with 15 records per page

-- Returns @RowsCountPerPage rows
-- After skipping the first (@PageNumber - 1) * @RowsCountPerPage rows
SELECT ID, FirstName, LastName
FROM Person.Person
ORDER BY ID
OFFSET (@PageNumber - 1) * @RowsCountPerPage ROWS
FETCH NEXT @RowsCountPerPage ROWS ONLY

The diamond problem

The "diamond problem" (sometimes referred to as the "deadly diamond of death") is an ambiguity that arises when two classes B and C inherit from A, and class D inherits from both B and C. If D calls a method defined in A (and does not override the method), and B and C have overridden that method differently, then from which class does it inherit: B, or C?


It is called the "diamond problem" because of the logical shape of the class inheritance diagram in this situation. Here, class A is at the top, both B and C separately beneath it, and D joins the two together at the bottom to form a diamond shape.

Ref: Wikipedia

Loose Coupling and Tight coupling

Tight coupling is when a group of classes are highly dependent on one another.
This scenario arises when a class assumes too many responsibilities, or when one concern is spread over many classes rather than having its own class.
Loose coupling is achieved by means of a design that promotes single-responsibility and separation of concerns.
A loosely-coupled class can be consumed and tested independently of other (concrete) classes.
Interfaces are a powerful tool to use for decoupling. Classes can communicate through interfaces rather than other concrete classes, and any class can be on the other end of that communication simply by implementing the interface.

Tight Coupling:

class CustomerRepository
{
    private readonly Database database;

    public CustomerRepository(Database database)
    {
        this.database = database;
    }

    public void Add(string CustomerName)
    {
        database.AddRow("Customer", CustomerName);
    }
}

class Database
{
    public void AddRow(string Table, string Value)
    {
    }
}

Loose Coupling:

class CustomerRepository
{
    private readonly IDatabase database;

    public CustomerRepository(IDatabase database)
    {
        this.database = database;
    }

    public void Add(string CustomerName)
    {
        database.AddRow("Customer", CustomerName);
    }
}

interface IDatabase
{
    void AddRow(string Table, string Value);
}

class Database : IDatabase
{
    public void AddRow(string Table, string Value)
    {
    }
} 

Great article on Stack Implementation

http://blogs.msdn.com/b/ericlippert/archive/2009/05/04/the-stack-is-an-implementation-detail-part-two.aspx

By Eric Lippert

How find Sql objects used in procedures

SELECT DISTINCT so.name
FROM syscomments sc
INNER JOIN sysobjects so ON sc.id=so.id
WHERE sc.TEXT LIKE '%Products%'

Enable Claims based authentication on an existing web application in SharePoint

When you provision a web application in SharePoint 2010 you get the option to enable Claims based authentication. However, after the provisioning there's no option in the GUI to turn it on. PowerShell saves the day again with the option to change from classic to claims based authentication using the lines below.

$WebAppName = "http://test:8001"
$account = "Administrator" 
$wa = get-SPWebApplication $WebAppName
Set-SPwebApplication $wa –AuthenticationProvider (New-SPAuthenticationProvider) 

–Zone Default

The user running these command should be a member of the SharePoint_Shell_Access role on the config DB, and a member of the WSS_ADMIN_WPG local group.

Scrum Master in Under 10 Minutes

Good video on SCRUM Methodology By Hamids