What is Single Sign On (SSO)? Federated Single Sign-On SAML 2.0 with ITfoxtec Saml2

Single sign-on (SSO) is a session and user authentication service that permits a user to use one set of login credentials (e.g., name and password) to access multiple applications.

Logging in multiple times can be eliminated with Single Sign On i.e. user has to login only once and can access web multiple applications. Implementing SSO with ITfoxtec SAML 2.0 in ASP.NET MVC is very simple. Below is the step by step approach to implement it.

1. Open visual studio, create a ASP.net MVC Application 
2. add itfoxtec.saml2 and itfoxtec.saml2.mvc from nuget pacakges 
3. check the AuthController in your controller folder 
4. Set the basic setting like Issuer url, Destination, AssertionConsumerServiceUrl
5. get the identity in AssertionConsumerService method using given below code
   var useridentity = saml2AuthnResponse.ClaimsIdentity as ClaimsIdentity; var username = useridentity.Claims.Where(c => c.Type == "username") .Select(c => c.Value).SingleOrDefault();

ASP.NET interview Question

1. Describe the role of inetinfo.exe, aspnet_isapi.dll and aspnet_wp.exe in the page loading process.

inetinfo.exe is the Microsoft IIS server running, handling ASP.NET requests among other things. When an ASP.NET request is received (usually a file with .aspx extension),the ISAPI filter aspnet_isapi.dll takes care of it by passing the request to the actual worker process aspnet_wp.exe.

2. What’s the difference between Response.Write() and Response.Output.Write()?

The latter one allows you to write formatted output.

3. What methods are fired during the page load?

Init() - when the page is instantiated,
Load() - when the page is loaded into server memory,
PreRender() - the brief moment before the page is displayed to the user as HTML,
Unload() - when page finishes loading.

4. Where does the Web page belong in the .NET Framework class hierarchy?
System.Web.UI.Page

5. Where do you store the information about the user’s locale?
System.Web.UI.Page.Culture

6. What’s the difference between Codebehind="MyCode.aspx.cs" and Src="MyCode.aspx.cs"? CodeBehind is relevant to Visual Studio.NET only.

7. What’s a bubbled event?
When you have a complex control, like DataGrid, writing an event processing routine for each object (cell, button, row, etc.) is quite tedious. The controls can bubble up their event handlers, allowing the main DataGrid event handler to take care of its constituents.

8. Suppose you want a certain ASP.NET function executed on MouseOver over a certain button. Where do you add an event handler?
It’s the Attributes property, the Add function inside that property. So btnSubmit.Attributes.Add("onMouseOver","someClientCode();")

9. What data type does the RangeValidator control support?
Integer, String and Date.

10. Explain the differences between Server-side and Client-side code?
Server-side code runs on the server. Client-side code runs in the clients’ browser.

11. What type of code (server or client) is found in a Code-Behind class?
Server-side code.

12. Should validation (did the user enter a real date) occur server-side or client-side? Why?
Client-side. This reduces an additional request to the server to validate the users input.

13. What does the "EnableViewState" property do? Why would I want it on or off?
It enables the viewstate on the page. It allows the page to save the users input on a form.

14. What is the difference between Server.Transfer and Response.Redirect? Why would I choose one over the other?

Server.Transfer is used to post a form to another page. Response.Redirect is used to redirect the user to another page or site.

15. Can you explain the difference between an ADO.NET Dataset and an ADO Recordset?

• A DataSet can represent an entire relational database in memory, complete with tables, relations, and views.
• A DataSet is designed to work without any continuing onnection to the original data source.
• Data in a DataSet is bulk-loaded, rather than being loaded on demand.
• There's no concept of cursor types in a DataSet.
• DataSets have no current record pointer You can use For Each loops to move through the data.
• You can store many edits in a DataSet, and write them to the original data source in a single operation.
• Though the DataSet is universal, other objects in ADO.NET come in different versions for different data sources.

16. Can you give an example of what might be best suited to place in the Application_Start and Session_Start subroutines?
This is where you can set the specific variables for the Application and Session objects.

17. If I’m developing an application that must accommodate multiple security levels though secure login and my ASP.NET web application is spanned across three web-servers (using round-robin load balancing) what would be the best approach to maintain login-in state for the users?
Maintain the login state security through a database.

18. Can you explain what inheritance is and an example of when you might use it?
When you want to inherit (use the functionality of) another class. Base Class Employee. A Manager class could be derived from the Employee base class.

19. Whats an assembly?
Assemblies are the building blocks of the .NET framework. Overview of assemblies from MSDN

20. Describe the difference between inline and code behind.
Inline code written along side the html in a page. Code-behind is code written in a separate file and referenced by the .aspx page.

21. Explain what a diffgram is, and a good use for one?
The DiffGram is one of the two XML formats that you can use to render DataSet object contents to XML. For reading database data to an XML file to be sent to a Web Service.

22. Whats MSIL, and why should my developers need an appreciation of it if at all?
MSIL is the Microsoft Intermediate Language. All .NET compatible languages will get converted to MSIL.

23. Which method do you invoke on the DataAdapter control to load your generated dataset with data?
The .Fill() method

24. Can you edit data in the Repeater control?
No, it just reads the information from its data source

25. Which template must you provide, in order to display data in a Repeater control?
ItemTemplate

26. How can you provide an alternating color scheme in a Repeater control?
Use the AlternatingItemTemplate

27. What property must you set, and what method must you call in your code, in order to bind the data from some data source to the Repeater control?
You must set the DataSource property and call the DataBind method.

28. What base class do all Web Forms inherit from?
The Page class.

29. Name two properties common in every validation control?
ControlToValidate property and Text property.

30. What tags do you need to add within the asp:datagrid tags to bind columns manually?
Set AutoGenerateColumns Property to false on the datagrid tag

31. What tag do you use to add a hyperlink column to the DataGrid?
<asp:HyperLinkColumn>

32. What is the transport protocol you use to call a Web service?
SOAP is the preferred protocol.

33. True or False: A Web service can only be written in .NET?
False

34. What does WSDL stand for?
(Web Services Description Language)

35. Where on the Internet would you look for Web services?
(http://www.uddi.org)

36. Which property on a Combo Box do you set with a column name, prior to setting the DataSource, to display data in the combo box?
DataTextField property

37. Which control would you use if you needed to make sure the values in two different controls matched?
CompareValidator Control

38. True or False: To test a Web service you must create a windows application or Web application to consume this service?
False, the webservice comes with a test page and it provides HTTP-GET method to test.

39. How many classes can a single .NET DLL contain?
It can contain many classes.

How to fix Font Awesome WebFont woff2 not found on Azure webapp Or Font awesome icon not shown in Azure website

If your are getting the error  fontawesome-webfont.woff2?v=4.6.3 not found but this file exist on webserver.

The fix is really simple.

You need to add the mime type in the config file for woff2.

<system.webServer>
  <staticContent>
    <remove fileExtension=".woff2" />
    <mimeMap fileExtension=".woff2" mimeType="font/woff2" />
  </staticContent>
</system.webServer>

After added this code you need to hard refresh your website or Ctrl+F5 

This program is blocked by group policy. For more information, contact your system administrator

If your find this error on godaddy server

Server Error in '/' Application.

---

This program is blocked by group policy. For more information, contact your system administrator

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ComponentModel.Win32Exception: This program is blocked by group policy. For more information, contact your system administrator

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Follow simple two steps

Code access security

1. Add trust level full to the system.web

<system.web>
    compilation debug="true" targetFramework="4.5.2"/>
    <httpRuntime targetFramework="4.5.2"/>
    <trust level="Full"/>             <!-- Just add this to the webconfig -->
 </system.web>

2.Remove the compilers in the system.codecom

<system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:6 /nowarn:1659;1699;1701" />
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:14 /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
    </compilers>
  </system.codedom>

<system.codedom>
              <!-- All is removed between the 2 tags-->
 </system.codedom>

SQL JOIN

SQL JOIN

The JOIN keyword is used in an SQL statement to query data from two or more tables, based on a relationship between certain columns in these tables.

Tables in a database are often related to each other with keys.

A primary key is a column (or a combination of columns) with a unique value for each row. Each primary key value must be unique within the table. The purpose is to bind data together, across tables, without repeating all of the data in every table.

Look at the "Persons" table:

P_Id	LastName	FirstName	Address	City
1	Hansen	Ola	Timoteivn 10	Sandnes
2	Svendson	Tove	Borgvn 23	Sandnes
3	Pettersen	Kari	Storgt 20	Stavanger

Note that the "P_Id" column is the primary key in the "Persons" table. This means that no two rows can have the same P_Id. The P_Id distinguishes two persons even if they have the same name.

Next, we have the "Orders" table:

O_Id	OrderNo	P_Id
1	77895	3
2	44678	3
3	22456	1
4	24562	1
5	34764	15

Note that the "O_Id" column is the primary key in the "Orders" table and that the "P_Id" column refers to the persons in the "Persons" table without using their names.

Notice that the relationship between the two tables above is the "P_Id" column.

Different SQL JOINs

Before we continue with examples, we will list the types of JOIN you can use, and the differences between them.

• JOIN: Return rows when there is at least one match in both tables
• LEFT JOIN: Return all rows from the left table, even if there are no matches in the right table
• RIGHT JOIN: Return all rows from the right table, even if there are no matches in the left table
• FULL JOIN: Return rows when there is a match in one of the tables

SQL INNER JOIN Example

The "Persons" table:

P_Id	LastName	FirstName	Address	City
1	Hansen	Ola	Timoteivn 10	Sandnes
2	Svendson	Tove	Borgvn 23	Sandnes
3	Pettersen	Kari	Storgt 20	Stavanger

The "Orders" table:

O_Id	OrderNo	P_Id
1	77895	3
2	44678	3
3	22456	1
4	24562	1
5	34764	15

Now we want to list all the persons with any orders.

We use the following SELECT statement:

SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo FROM Persons INNER JOIN Orders ON Persons.P_Id=Orders.P_Id ORDER BY Persons.LastName

The result-set will look like this:

LastName	FirstName	OrderNo
Hansen	Ola	22456
Hansen	Ola	24562
Pettersen	Kari	77895
Pettersen	Kari	44678

The INNER JOIN keyword return rows when there is at least one match in both tables. If there are rows in "Persons" that do not have matches in "Orders", those rows will NOT be listed.

SQL LEFT JOIN Example

The "Persons" table:

P_Id	LastName	FirstName	Address	City
1	Hansen	Ola	Timoteivn 10	Sandnes
2	Svendson	Tove	Borgvn 23	Sandnes
3	Pettersen	Kari	Storgt 20	Stavanger

The "Orders" table:

O_Id	OrderNo	P_Id
1	77895	3
2	44678	3
3	22456	1
4	24562	1
5	34764	15

Now we want to list all the persons and their orders - if any, from the tables above.

We use the following SELECT statement:

SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo FROM Persons LEFT JOIN Orders ON Persons.P_Id=Orders.P_Id ORDER BY Persons.LastName

The result-set will look like this:

LastName	FirstName	OrderNo
Hansen	Ola	22456
Hansen	Ola	24562
Pettersen	Kari	77895
Pettersen	Kari	44678
Svendson	Tove

The LEFT JOIN keyword returns all the rows from the left table (Persons), even if there are no matches in the right table (Orders).

SQL RIGHT JOIN Example

The "Persons" table:

P_Id	LastName	FirstName	Address	City
1	Hansen	Ola	Timoteivn 10	Sandnes
2	Svendson	Tove	Borgvn 23	Sandnes
3	Pettersen	Kari	Storgt 20	Stavanger

The "Orders" table:

O_Id	OrderNo	P_Id
1	77895	3
2	44678	3
3	22456	1
4	24562	1
5	34764	15

Now we want to list all the orders with containing persons - if any, from the tables above.

We use the following SELECT statement:

SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo FROM Persons RIGHT JOIN Orders ON Persons.P_Id=Orders.P_Id ORDER BY Persons.LastName

The result-set will look like this:

LastName	FirstName	OrderNo
Hansen	Ola	22456
Hansen	Ola	24562
Pettersen	Kari	77895
Pettersen	Kari	44678
		34764

The RIGHT JOIN keyword returns all the rows from the right table (Orders), even if there are no matches in the left table (Persons).

SQL FULL JOIN Example

The "Persons" table:

P_Id	LastName	FirstName	Address	City
1	Hansen	Ola	Timoteivn 10	Sandnes
2	Svendson	Tove	Borgvn 23	Sandnes
3	Pettersen	Kari	Storgt 20	Stavanger

The "Orders" table:

O_Id	OrderNo	P_Id
1	77895	3
2	44678	3
3	22456	1
4	24562	1
5	34764	15

Now we want to list all the persons and their orders, and all the orders with their persons.

We use the following SELECT statement:

SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo FROM Persons FULL JOIN Orders ON Persons.P_Id=Orders.P_Id ORDER BY Persons.LastName

The result-set will look like this:

LastName	FirstName	OrderNo
Hansen	Ola	22456
Hansen	Ola	24562
Pettersen	Kari	77895
Pettersen	Kari	44678
Svendson	Tove
		34764

The FULL JOIN keyword returns all the rows from the left table (Persons), and all the rows from the right table (Orders). If there are rows in "Persons" that do not have matches in "Orders", or if there are rows in "Orders" that do not have matches in "Persons", those rows will be listed as well.

The SQL UNION Operator

The UNION operator is used to combine the result-set of two or more SELECT statements.
Notice that each SELECT statement within the UNION must have the same number of columns. The columns must also have similar data types. Also, the columns in each SELECT statement must be in the same order.

SQL UNION Syntax

SELECT column_name(s) FROM table_name1 UNION SELECT column_name(s) FROM table_name2

Note: The UNION operator selects only distinct values by default. To allow duplicate values, use UNION ALL.

SQL UNION ALL Syntax

SELECT column_name(s) FROM table_name1 UNION ALL SELECT column_name(s) FROM table_name2

PS: The column names in the result-set of a UNION are always equal to the column names in the first SELECT statement in the UNION.

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SQL UNION Example

Look at the following tables:
"Employees_Norway":

E_ID	E_Name
01	Hansen, Ola
02	Svendson, Tove
03	Svendson, Stephen
04	Pettersen, Kari

"Employees_USA":

E_ID	E_Name
01	Turner, Sally
02	Kent, Clark
03	Svendson, Stephen
04	Scott, Stephen

Now we want to list all the different employees in Norway and USA.
We use the following SELECT statement:

SELECT E_Name FROM Employees_Norway UNION SELECT E_Name FROM Employees_USA

The result-set will look like this:

E_Name

Hansen, Ola

Svendson, Tove

Svendson, Stephen

Pettersen, Kari

Turner, Sally

Kent, Clark

Scott, Stephen

Note: This command cannot be used to list all employees in Norway and USA. In the example above we have two employees with equal names, and only one of them will be listed. The UNION command selects only distinct values.

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SQL UNION ALL Example

Now we want to list all employees in Norway and USA:

SELECT E_Name FROM Employees_Norway UNION ALL SELECT E_Name FROM Employees_USA

Result

E_Name

Hansen, Ola

Svendson, Tove

Svendson, Stephen

Pettersen, Kari

Turner, Sally

Kent, Clark

Svendson, Stephen

Scott, Stephen