All About .Net

Tuesday, December 5, 2017

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Sunday, November 12, 2017

1 Partial class
2 Generics
3 Static classes
4 Generator functionality
5 Anonymous delegates
6 Delegate covariance and contravariance
7 The accessibility of property accessors can be set independently
8 Nullable types
9 Null-coalescing operator

Partial class
Partial classes allow implementation of a class to be spread between several files, with each file containing one or more class members. It is useful primarily when parts of a class are generated automatically. For example, the feature is heavily used by code-generating user interface designers in Visual Studio.

file1.cs:

public partial class MyClass
{
public void MyMethod1()
{
// Manually written code
}
}
file2.cs:

public partial class MyClass
{
public void MyMethod2()
{
// Automatically generated code
}
}

Generics
Generics, or parameterized types, or parametric polymorphism is a .NET 2.0 feature supported by C# and Visual Basic. Unlike C++ templates, .NET parameterized types are instantiated at runtime rather than by the compiler; hence they can be cross-language whereas C++ templates cannot. They support some features not supported directly by C++ templates such as type constraints on generic parameters by use of interfaces. On the other hand, C# does not support non-type generic parameters. Unlike generics in Java, .NET generics use reification to make parameterized types first-class objects in the CLI Virtual Machine, which allows for optimizations and preservation of the type information.[1]

Static classes
Static classes are classes that cannot be instantiated or inherited from, and that only allow static members. Their purpose is similar to that of modules in many procedural languages.

Generator functionality
The .NET 2.0 Framework allowed C# to introduce an iterator that provides generator functionality, using a yield return construct similar to yield in Python.[2] With a yield return, the function automatically keeps its state during the iteration.

// Method that takes an iterable input (possibly an array)
// and returns all even numbers.
public static IEnumerable<int> GetEven(IEnumerable<int> numbers)
{
foreach (int i in numbers)
{
if (i % 2 == 0)
yield return i;
}
}
There is also a yield break statement, in which control is unconditionally returned to the caller of the iterator. There is an implicit yield break at the end of each generator method.

Anonymous delegates
As a precursor to the lambda functions introduced in C# 3.0, C#2.0 added anonymous delegates. These provide closure-like functionality to C#.[3] Code inside the body of an anonymous delegate has full read/write access to local variables, method parameters, and class members in scope of the delegate, excepting out and ref parameters. For example:-

int SumOfArrayElements(int[] array)
{
int sum = 0;
Array.ForEach(array,
delegate(int x)
{
sum += x;
}
);
return sum;
}
Unlike some closure implementations, each anonymous delegate instance has access to the same relative memory location for each bound variable, rather than to the actual values at each creation. See a fuller discussion of this distinction.

Delegate covariance and contravariance
Conversions from method groups to delegate types are covariant and contravariant in return and parameter types, respectively.[4]

The accessibility of property accessors can be set independently
Example:

string status = string.Empty;

public string Status
{
get { return status; } // anyone can get value of this property,
protected set { status = value; } // but only derived classes can change it
}

Nullable types
Nullable value types (denoted by a question mark, e.g. int? i = null;) which add null to the set of allowed values for any value type. This provides improved interaction with SQL databases, which can have nullable columns of types corresponding to C# primitive types: an SQL INTEGER NULL column type directly translates to the C# int?.

Nullable types received an improvement at the end of August 2005, shortly before the official launch, to improve their boxing characteristics: a nullable variable which is assigned null is not actually a null reference, but rather an instance of struct Nullable<T> with property HasValue equal to false. When boxed, the Nullable instance itself is boxed, and not the value stored in it, so the resulting reference would always be non-null, even for null values. The following code illustrates the corrected flaw:

int? i = null;
object o = i;
if (o == null)
System.Console.WriteLine("Correct behaviour - runtime version from September 2010 or later");
else
System.Console.WriteLine("Incorrect behaviour - pre-release runtime (from before September 2010)");

When copied into objects, the official release boxes values from Nullable instances, so null values and null references are considered equal. The late nature of this fix caused some controversy[5] , since it required core-CLR changes affecting not only .NET2, but all dependent technologies (including C#, VB, SQL Server 2005 and Visual Studio 2005).

Null-coalescing operator
The ?? operator is called the null-coalescing operator and is used to define a default value for nullable value types as well as reference types. It returns the left-hand operand if it is not null; otherwise it returns the right operand.[6]

object nullObj = null;
object obj = new Object();
return nullObj ?? obj; // returns obj
The primary use of this operator is to assign a nullable type to a non-nullable type with an easy syntax:

int? i = null;
int j = i ?? 0; // If i is not null, initialize j to i. Else (if i is null), initialize j to 0.

Sunday, September 17, 2017

Customized Authentication Filters in ASP.MVC5

As we studied in last article, Filters are used to inject logic at the different levels of request processing. Below is the filters execution sequence:

Authentication Filters ==> Authorization filter ==> Action filter ==> Result filter ==> Exceptionfilter

The authentication filter executes before any other filter

The authorization filter executes after Authentication filter and action method, or before any other filter

The action filter executes before and after any action method

The result filter executes before and after the execution of any action result

The exception filter executes only if any action methods, filters, or results throws an exception

Create a new class

Implement IAuthenticationFilter Interface

Derive it from ActionFilterAttribute

Override the OnAuthentication method to run logic before the action methodg

OnAuthentication Method

The program invokes Authentication Filters by calling this method. This method creates the AuthenticationContext. AuthenticationContext has information about performing authentication. We can use this information to make authentication decisions based on the current context.

OnAuthenticationChallenge Method

This method executes after the OnAuthentication method. We can use the OnAuthenticationChallenge method to perform additional tasks on request. This method creates an AuthenticationChallengeContext the same way as OnAuthentication.

Tuesday, November 29, 2016

Generics in C-sharp(C#)

Generics allow you to delay the specification of the data type of programming elements in a class or a method, until it is actually used in the program. In other words, generics allow you to write a class or method that can work with any data type.

Some of the most useful features of Generics are:

type safety.
Eliminates type mismatch at run time.
Better performance with value type.
Does not incur inter conversion.

Generic | Creation of Generic List <T>

The procedure for using a generic List collection is similar to the concept of an array. We do declare the List, extend its sub members and then access the extended sub members of that List.

For example:

List<int> myInts = new List<int>();

myInts.Add(1);

myInts.Add(2);

myInts.Add(3);

for (int i = 0; i < myInts.Count; i++)

{

Console.WriteLine("MyInts: {0}", myInts[i]);

}

Generic | Handling Dictionary <TKey , TValue>

A Dictionary is nothing but a generic collection that works with key/value pairs. A Dictionary works similarly to the way of non-generic collections such as a HashTable. The only difference between a Dictionary and a HashTable is that it operates on the object type.

The complete scenario of a Dictionary collection is explained through the example of customers.

For example:

public class Customer

{

public Customer(int id, string name)

{

ID = id;

Name = name;

}

private int m_id;

public int ID

{

get { return m_id; }

set { m_id = value; }

}

private string m_name;

public string Name

{

get { return m_name; }

set { m_name = value; }

}

Generic | Dictionary Collection

This code part represents dictionary handling with customer extended objects. It also explains how entries are extracted from a Dictionary.

For example:

Dictionary<int, Customer> customers = new Dictionary<int, Customer>();

Customer cust1 = new Customer(1, "Cust 1");

Customer cust2 = new Customer(2, "Cust 2");

Customer cust3 = new Customer(3, "Cust 3");

customers.Add(cust1.ID, cust1);

customers.Add(cust2.ID, cust2);

customers.Add(cust3.ID, cust3);

foreach (KeyValuePair<int, Customer> custKeyVal in customers)

{

Console.WriteLine(

"Customer ID: {0}, Name: {1}",

custKeyVal.Key,

custKeyVal.Value.Name);

}

Monday, November 28, 2016

ASP.NET MVC interview question

1) What is MVC?
MVC is a pattern which is used to split the application's implementation logic into three components: models, views, and controllers.

2) What is MVC (Model View Controller)?
MVC is an architectural pattern which separates the representation and user interaction. It’s divided into three broader sections, Model, View, and Controller. Below is how each one of them handles the task.

The View is responsible for the look and feel.
Model represents the real world object and provides data to the View.
The Controller is responsible for taking the end user request and loading the appropriate Model and View.

3) What are the benefits of using MVC?
There are two big benefits of MVC:

Separation of concerns is achieved as we are moving the code-behind to a separate class file. By moving the binding code to a separate class file we can reuse the code to a great extent.
Automated UI testing is possible because now the behind code (UI interaction code) has moved to a simple .NET class. This gives us opportunity to write unit tests and automate manual testing.

4) Can you explain the page life cycle of MVC?
Below are the processed followed in the sequence -
App initialization
Routing
Instantiate and execute controller
Locate and invoke controller action
Instantiate and render view.

5) What are the advantages of MVC over ASP.NET?
Provides a clean separation of concerns among UI (Presentation layer), model (Transfer objects/Domain Objects/Entities) and Business Logic (Controller).
Easy to UNIT Test.
Improved reusability of model and views. We can have multiple views which can point to the same model and vice versa.
Improved structuring of the code.

6) What is the use of ViewModel in MVC?

ViewModel is a plain class with properties, which is used to bind it to strongly typed view. ViewModel can have the validation rules defined for its properties using data annotations.

7) What is Razor View Engine?
Razor is the first major update to render HTML in ASP.Net MVC 3. Razor was designed specifically for view engine syntax. Main focus of this would be to simplify and code-focused templating for HTML generation.

8) What are Actions in ASP.Net MVC?
Actions are the methods in Controller class which is responsible for returning the view or json data. Action will mainly have return type : "ActionResult" and it will be invoked from method : "InvokeAction()" called by controller.

9) How to enable Attribute Routing?
Just add @Model.CustomerName the method : "MapASP.Net MVCAttributeRoutes()" to enable attribute routing

10) Explain JSON Binding?
JavaScript Object Notation (JSON) binding support started from ASP.Net MVC3 onwards via the new JsonValueProviderFactory, which allows the action methods to accept and model-bind data in JSON format. This is useful in Ajax scenarios like client templates and data binding that need to post data back to the server.

11) which is a better fit, Razor or ASPX?
As per Microsoft, Razor is more preferred because it’s light weight and has simple syntaxes.

12) How to implement AJAX in MVC?
You can implement AJAX in two ways in MVC:

13) AJAX libraries
jQuery
Below is a simple sample of how to implement AJAX by using the “AJAX” helper library. In the below code you can see we have a simple form which is created by using the Ajax.BeginForm syntax. This form calls a controller action called getCustomer. So now the submit action click will be an asynchronous AJAX call.

Hide Copy Code
<script language="javascript">
function OnSuccess(data1)
{
// Do something here
}
</script>

14) What are Code Blocks in Views?
Unlike code expressions that are evaluated and sent to the response, it is the blocks of code that are executed. This is useful for declaring variables which we may be required to be used later.

@{
int x = 123;
string y = "aa";
}

15) What is RouteConfig.cs in ASP.Net MVC 4?
"RouteConfig.cs" holds the routing configuration for ASP.Net MVC. RouteConfig will be initialized on Application_Start event registered in Global.asax.

16) What is PartialView in ASP.Net MVC?
PartialView is similar to UserControls in traditional web forms. For re-usability purpose partial views are used. Since it's been shared with multiple views these are kept in shared folder. Partial Views can be rendered in following ways :

Html.Partial()
Html.RenderPartial()

17) How can we determine action invoked from HTTP GET or HTTP POST?
This can be done in following way : Use class : "HttpRequestBase" and use the method : "HttpMethod" to determine the action request type.

18) What is ViewData?

Viewdata contains the key, value pairs as dictionary and this is derived from class – “ViewDataDictionary“. In action method we are setting the value for viewdata and in view the value will be fetched by typecasting.

19) How we can add the CSS in MVC?

Below is the sample code snippet to add css to razor views –

<link rel="StyleSheet" href="/@Href(~Content/Site.css")" type="text/css"/>

20) Mention some action filters which are used regularly in MVC?

Below are some action filters used –

Authentication
Authorization
HandleError
OutputCache

21) Explain Keep method in Tempdata in MVC?

As explained above in case data in Tempdata has been read in current request only then “Keep” method has been used to make it available for the subsequent request.

@TempData[“TestData”];
TempData.Keep(“TestData”);

22) What is the use of the dispose method in C# ?

dispose method are used for forcefully garbage collection..!!!

23) Major and importance difference between for and foreach loop ?

a for loop is a construct that says "perform this operation n. times".a foreach loop is a construct that says "perform this operation against each value/object in this IEnumerable"

24) What is data dictionary?
Dictionaries provide fast lookups, based on keys, to get values. With them, we use keys and values of any type, including int and string.

Sunday, November 27, 2016

Get Yahoo Contact for C#

Create new Website

Create AppCode Folder

Create OAuthBase.cs in AppCode Folder like

using System;

using System.Security.Cryptography;

using System.Collections.Generic;

using System.Text;

using System.Web;

namespace OAuth

{

public class OAuthBase

{

/// <summary>

/// Provides a predefined set of algorithms that are supported officially by the protocol

/// </summary>

public enum SignatureTypes

{

HMACSHA1,

PLAINTEXT,

RSASHA1

}

/// <summary>

/// Provides an internal structure to sort the query parameter

/// </summary>

protected class QueryParameter

{

private string name = null;

private string value = null;

public QueryParameter(string name, string value)

{

this.name = name;

this.value = value;

}

public string Name

{

get { return name; }

}

public string Value

{

get { return value; }

}

/// <summary>

/// Comparer class used to perform the sorting of the query parameters

/// </summary>

protected class QueryParameterComparer : IComparer<QueryParameter>

{

#region IComparer<QueryParameter> Members

public int Compare(QueryParameter x, QueryParameter y)

{

if (x.Name == y.Name)

{

return string.Compare(x.Value, y.Value);

}

else

{

return string.Compare(x.Name, y.Name);

}

#endregion

}

protected const string OAuthVersion = "1.0";

protected const string OAuthParameterPrefix = "oauth_";

// List of know and used oauth parameters' names

protected const string OAuthConsumerKeyKey = "oauth_consumer_key";

protected const string OAuthCallbackKey = "oauth_callback";

protected const string OAuthVersionKey = "oauth_version";

protected const string OAuthSignatureMethodKey = "oauth_signature_method";

protected const string OAuthSignatureKey = "oauth_signature";

protected const string OAuthTimestampKey = "oauth_timestamp";

protected const string OAuthNonceKey = "oauth_nonce";

protected const string OAuthTokenKey = "oauth_token";

protected const string OAuthTokenSecretKey = "oauth_token_secret";

protected const string HMACSHA1SignatureType = "HMAC-SHA1";

protected const string PlainTextSignatureType = "PLAINTEXT";

protected const string RSASHA1SignatureType = "RSA-SHA1";

protected Random random = new Random();

protected string unreservedChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~";

/// <summary>

/// Helper function to compute a hash value

/// </summary>

/// <param name="hashAlgorithm">The hashing algoirhtm used. If that algorithm needs some initialization, like HMAC and its derivatives, they should be initialized prior to passing it to this function</param>

/// <param name="data">The data to hash</param>

/// <returns>a Base64 string of the hash value</returns>

private string ComputeHash(HashAlgorithm hashAlgorithm, string data)

{

if (hashAlgorithm == null)

{

throw new ArgumentNullException("hashAlgorithm");

}

if (string.IsNullOrEmpty(data))

{

throw new ArgumentNullException("data");

}

byte[] dataBuffer = System.Text.Encoding.ASCII.GetBytes(data);

byte[] hashBytes = hashAlgorithm.ComputeHash(dataBuffer);

return Convert.ToBase64String(hashBytes);

}

/// <summary>

/// Internal function to cut out all non oauth query string parameters (all parameters not begining with "oauth_")

/// </summary>

/// <param name="parameters">The query string part of the Url</param>

/// <returns>A list of QueryParameter each containing the parameter name and value</returns>

private List<QueryParameter> GetQueryParameters(string parameters)

{

if (parameters.StartsWith("?"))

{

parameters = parameters.Remove(0, 1);

}

List<QueryParameter> result = new List<QueryParameter>();

if (!string.IsNullOrEmpty(parameters))

{

string[] p = parameters.Split('&');

foreach (string s in p)

{

if (!string.IsNullOrEmpty(s) && !s.StartsWith(OAuthParameterPrefix))

{

if (s.IndexOf('=') > -1)

{

string[] temp = s.Split('=');

result.Add(new QueryParameter(temp[0], temp[1]));

}

else

{

result.Add(new QueryParameter(s, string.Empty));

}

return result;

}

/// <summary>

/// This is a different Url Encode implementation since the default .NET one outputs the percent encoding in lower case.

/// While this is not a problem with the percent encoding spec, it is used in upper case throughout OAuth

/// </summary>

/// <param name="value">The value to Url encode</param>

/// <returns>Returns a Url encoded string</returns>

protected string UrlEncode(string value)

{

StringBuilder result = new StringBuilder();

foreach (char symbol in value)

{

if (unreservedChars.IndexOf(symbol) != -1)

{

result.Append(symbol);

}

else

{

result.Append('%' + String.Format("{0:X2}", (int)symbol));

}

return result.ToString();

}

/// <summary>

/// Normalizes the request parameters according to the spec

/// </summary>

/// <param name="parameters">The list of parameters already sorted</param>

/// <returns>a string representing the normalized parameters</returns>

protected string NormalizeRequestParameters(IList<QueryParameter> parameters)

{

StringBuilder sb = new StringBuilder();

QueryParameter p = null;

for (int i = 0; i < parameters.Count; i++)

{

p = parameters[i];

sb.AppendFormat("{0}={1}", p.Name, p.Value);

if (i < parameters.Count - 1)

{

sb.Append("&");

}

return sb.ToString();

}

/// <summary>

/// Generate the signature base that is used to produce the signature

/// </summary>

/// <param name="url">The full url that needs to be signed including its non OAuth url parameters</param>

/// <param name="consumerKey">The consumer key</param>

/// <param name="token">The token, if available. If not available pass null or an empty string</param>

/// <param name="tokenSecret">The token secret, if available. If not available pass null or an empty string</param>

/// <param name="httpMethod">The http method used. Must be a valid HTTP method verb (POST,GET,PUT, etc)</param>

/// <param name="signatureType">The signature type. To use the default values use <see cref="OAuthBase.SignatureTypes">OAuthBase.SignatureTypes</see>.</param>

/// <returns>The signature base</returns>

public string GenerateSignatureBase(Uri url, string consumerKey, string token, string tokenSecret, string httpMethod, string timeStamp, string nonce, string signatureType, out string normalizedUrl, out string normalizedRequestParameters)

{

if (token == null)

{

token = string.Empty;

}

if (tokenSecret == null)

{

tokenSecret = string.Empty;

}

if (string.IsNullOrEmpty(consumerKey))

{

throw new ArgumentNullException("consumerKey");

}

if (string.IsNullOrEmpty(httpMethod))

{

throw new ArgumentNullException("httpMethod");

}

if (string.IsNullOrEmpty(signatureType))

{

throw new ArgumentNullException("signatureType");

}

normalizedUrl = null;

normalizedRequestParameters = null;

List<QueryParameter> parameters = GetQueryParameters(url.Query);

parameters.Add(new QueryParameter(OAuthVersionKey, OAuthVersion));

parameters.Add(new QueryParameter(OAuthNonceKey, nonce));

parameters.Add(new QueryParameter(OAuthTimestampKey, timeStamp));

parameters.Add(new QueryParameter(OAuthSignatureMethodKey, signatureType));

parameters.Add(new QueryParameter(OAuthConsumerKeyKey, consumerKey));

if (!string.IsNullOrEmpty(token))

{

parameters.Add(new QueryParameter(OAuthTokenKey, token));

}

parameters.Sort(new QueryParameterComparer());

normalizedUrl = string.Format("{0}://{1}", url.Scheme, url.Host);

if (!((url.Scheme == "http" && url.Port == 80) || (url.Scheme == "https" && url.Port == 443)))

{

normalizedUrl += ":" + url.Port;

}

normalizedUrl += url.AbsolutePath;

normalizedRequestParameters = NormalizeRequestParameters(parameters);

StringBuilder signatureBase = new StringBuilder();

signatureBase.AppendFormat("{0}&", httpMethod.ToUpper());

signatureBase.AppendFormat("{0}&", UrlEncode(normalizedUrl));

signatureBase.AppendFormat("{0}", UrlEncode(normalizedRequestParameters));

return signatureBase.ToString();

}

/// <summary>

/// Generate the signature value based on the given signature base and hash algorithm

/// </summary>

/// <param name="signatureBase">The signature based as produced by the GenerateSignatureBase method or by any other means</param>

/// <param name="hash">The hash algorithm used to perform the hashing. If the hashing algorithm requires initialization or a key it should be set prior to calling this method</param>

/// <returns>A base64 string of the hash value</returns>

public string GenerateSignatureUsingHash(string signatureBase, HashAlgorithm hash)

{

return ComputeHash(hash, signatureBase);

}

/// <summary>

/// Generates a signature using the HMAC-SHA1 algorithm

/// </summary>

/// <param name="url">The full url that needs to be signed including its non OAuth url parameters</param>

/// <param name="consumerKey">The consumer key</param>

/// <param name="consumerSecret">The consumer seceret</param>

/// <param name="token">The token, if available. If not available pass null or an empty string</param>

/// <param name="tokenSecret">The token secret, if available. If not available pass null or an empty string</param>

/// <param name="httpMethod">The http method used. Must be a valid HTTP method verb (POST,GET,PUT, etc)</param>

/// <returns>A base64 string of the hash value</returns>

public string GenerateSignature(Uri url, string consumerKey, string consumerSecret, string token, string tokenSecret, string httpMethod, string timeStamp, string nonce, out string normalizedUrl, out string normalizedRequestParameters)

{

return GenerateSignature(url, consumerKey, consumerSecret, token, tokenSecret, httpMethod, timeStamp, nonce, SignatureTypes.HMACSHA1, out normalizedUrl, out normalizedRequestParameters);

}

/// <summary>

/// Generates a signature using the specified signatureType

/// </summary>

/// <param name="url">The full url that needs to be signed including its non OAuth url parameters</param>

/// <param name="consumerKey">The consumer key</param>

/// <param name="consumerSecret">The consumer seceret</param>

/// <param name="token">The token, if available. If not available pass null or an empty string</param>

/// <param name="tokenSecret">The token secret, if available. If not available pass null or an empty string</param>

/// <param name="httpMethod">The http method used. Must be a valid HTTP method verb (POST,GET,PUT, etc)</param>

/// <param name="signatureType">The type of signature to use</param>

/// <returns>A base64 string of the hash value</returns>

public string GenerateSignature(Uri url, string consumerKey, string consumerSecret, string token, string tokenSecret, string httpMethod, string timeStamp, string nonce, SignatureTypes signatureType, out string normalizedUrl, out string normalizedRequestParameters)

{

normalizedUrl = null;

normalizedRequestParameters = null;

switch (signatureType)

{

case SignatureTypes.PLAINTEXT:

return HttpUtility.UrlEncode(string.Format("{0}&{1}", consumerSecret, tokenSecret));

case SignatureTypes.HMACSHA1:

string signatureBase = GenerateSignatureBase(url, consumerKey, token, tokenSecret, httpMethod, timeStamp, nonce, HMACSHA1SignatureType, out normalizedUrl, out normalizedRequestParameters);

HMACSHA1 hmacsha1 = new HMACSHA1();

hmacsha1.Key = Encoding.ASCII.GetBytes(string.Format("{0}&{1}", UrlEncode(consumerSecret), string.IsNullOrEmpty(tokenSecret) ? "" : UrlEncode(tokenSecret)));

return GenerateSignatureUsingHash(signatureBase, hmacsha1);

case SignatureTypes.RSASHA1:

throw new NotImplementedException();

default:

throw new ArgumentException("Unknown signature type", "signatureType");

}

/// <summary>

/// Generate the timestamp for the signature

/// </summary>

/// <returns></returns>

public virtual string GenerateTimeStamp()

{

// Default implementation of UNIX time of the current UTC time

TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);

string timeStamp = ts.TotalSeconds.ToString();

timeStamp = timeStamp.Substring(0, timeStamp.IndexOf("."));

return timeStamp;

}

/// <summary>

/// Generate a nonce

/// </summary>

/// <returns></returns>

public virtual string GenerateNonce()

{

// Just a simple implementation of a random number between 123400 and 9999999

return random.Next(123400, 9999999).ToString();

}

Download OAuth.Net.Common.dll and reference to bin folder

Create oauth-test.aspx page like

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="oauth-test.aspx.cs" Inherits="test_oauth_test" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<title>Untitled Page</title>

</head>

<body>

<div>

<asp:Button ID="Button1" runat="server" Text="Connect to Yahoo!" OnClick="Button1_Click" />

<asp:Label runat="server" ID="ResponseMessage1"></asp:Label>

<asp:GridView ID="grvMyFriends" runat="server" AutoGenerateColumns="false" CellPadding="5"

GridLines="None">

<asp:TemplateField HeaderText="Email">

<%# Container.DataItem %>

</ItemTemplate>

</asp:TemplateField>

</Columns>

No Friend List Found

</EmptyDataTemplate>

</asp:GridView>

</div>

</form>

</body>

</html>

Create oauth-test.aspx.cs file like

using System;

using System.Configuration;

using System.Data;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Net;

using System.IO;

using OAuth.Net.Common;

using OAuth.Net.Components;

using OAuth.Net.Consumer;

using OAuth;

using System.Text;

using System.Xml;

using System.Collections;

using System.Collections.Generic;

using System.Net.Mail;

using System.Text.RegularExpressions;

public partial class test_oauth_test : System.Web.UI.Page

{

string ConsumerKey = ConfigurationManager.AppSettings["ConsumerKey"].ToString();

string ConsumerSecret = ConfigurationManager.AppSettings["ConsumerSecret"].ToString();

public string OauthVerifier

{

get

{

try

{

if (!string.IsNullOrEmpty(Session["Oauth_Verifier"].ToString()))

return Session["Oauth_Verifier"].ToString();

else

return string.Empty;

}

catch

{

return string.Empty;

}

set

{

Session["Oauth_Verifier"] = value;

}

public string OauthToken

{

get

{

if (!string.IsNullOrEmpty(Session["Oauth_Token"].ToString()))

return Session["Oauth_Token"].ToString();

else

return string.Empty;

}

set

{

Session["Oauth_Token"] = value;

}

public string OauthTokenSecret

{

get

{

if (!string.IsNullOrEmpty(Session["Oauth_Token_Secret"].ToString()))

return Session["Oauth_Token_Secret"].ToString();

else

return string.Empty;

}

set

{

Session["Oauth_Token_Secret"] = value;

}

public string OauthSessionHandle

{

get

{

if (!string.IsNullOrEmpty(Session["Oauth_Session_Handle"].ToString()))

return Session["Oauth_Session_Handle"].ToString();

else

return string.Empty;

}

set

{

Session["Oauth_Session_Handle"] = value;

}

public string OauthYahooGuid

{

get

{

try

{

if (!string.IsNullOrEmpty(Session["Oauth_Yahoo_Guid"].ToString()))

return Session["Oauth_Yahoo_Guid"].ToString();

else

return string.Empty;

}

catch

{

return string.Empty;

}

set

{

Session["Oauth_Yahoo_Guid"] = value;

}

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

string oauth_token = Request["oauth_token"];

string oauth_verifier = Request["oauth_verifier"];

if (!string.IsNullOrEmpty(oauth_verifier) && oauth_verifier != "")

{

Button1.Visible = false;

OauthToken = oauth_token;

OauthVerifier = oauth_verifier;

RegisterStartupScript("refresh", "<script type='text/javascript'>window.opener.location = 'oauth-test.aspx'; self.close();</script>");

}

else if (!string.IsNullOrEmpty(OauthVerifier))

{

Button1.Visible = false;

if (string.IsNullOrEmpty(OauthYahooGuid))

GetAccessToken(OauthToken, OauthVerifier);

//RefreshToken();

RetriveContacts();

}

private string GetRequestToken()

{

string authorizationUrl = string.Empty;

OAuthBase oauth = new OAuthBase();

Uri uri = new Uri("https://api.login.yahoo.com/oauth/v2/get_request_token");

string nonce = oauth.GenerateNonce();

string timeStamp = oauth.GenerateTimeStamp();

string normalizedUrl;

string normalizedRequestParameters;

string sig = oauth.GenerateSignature(uri, ConsumerKey, ConsumerSecret, string.Empty, string.Empty, "GET", timeStamp, nonce, OAuthBase.SignatureTypes.PLAINTEXT, out normalizedUrl, out normalizedRequestParameters); //OAuthBase.SignatureTypes.HMACSHA1

StringBuilder sbRequestToken = new StringBuilder(uri.ToString());

sbRequestToken.AppendFormat("?oauth_nonce={0}&", nonce);

sbRequestToken.AppendFormat("oauth_timestamp={0}&", timeStamp);

sbRequestToken.AppendFormat("oauth_consumer_key={0}&", ConsumerKey);

sbRequestToken.AppendFormat("oauth_signature_method={0}&", "PLAINTEXT"); //HMAC-SHA1

sbRequestToken.AppendFormat("oauth_signature={0}&", sig);

sbRequestToken.AppendFormat("oauth_version={0}&", "1.0");

sbRequestToken.AppendFormat("oauth_callback={0}", HttpUtility.UrlEncode("http://localhost:7450/GetYahooContact/oauth-test.aspx"));

//Response.Write(sbRequestToken.ToString());

//Response.End();

try

{

string returnStr = string.Empty;

string[] returnData;

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(sbRequestToken.ToString());

HttpWebResponse res = (HttpWebResponse)req.GetResponse();

StreamReader streamReader = new StreamReader(res.GetResponseStream());

returnStr = streamReader.ReadToEnd();

returnData = returnStr.Split(new Char[] { '&' });

//Response.Write(returnStr);

int index;

if (returnData.Length > 0)

{

//index = returnData[0].IndexOf("=");

//string oauth_token = returnData[0].Substring(index + 1);

//Session["Oauth_Token"] = oauth_token;

index = returnData[1].IndexOf("=");

string oauth_token_secret = returnData[1].Substring(index + 1);

OauthTokenSecret = oauth_token_secret;

//index = returnData[2].IndexOf("=");

//int oauth_expires_in;

//Int32.TryParse(returnData[2].Substring(index + 1), out oauth_expires_in);

//Session["Oauth_Expires_In"] = oauth_expires_in;

index = returnData[3].IndexOf("=");

string oauth_request_auth_url = returnData[3].Substring(index + 1);

authorizationUrl = HttpUtility.UrlDecode(oauth_request_auth_url);

}

catch (WebException ex)

{

Response.Write(ex.Message);

}

return authorizationUrl;

}

private void RedirectUserForAuthorization(string authorizationUrl)

{

//Response.Redirect(authorizationUrl);

RegisterStartupScript("openwin", "<script type='text/javascript'>window.open('" + authorizationUrl + "','mywindow', 'left=250,top=50,menubar=0,resizable=0,location=1,toolbar=0,status=1,scrollbars=0,width=500,height=455');</script>");

}

private void GetAccessToken(string oauth_token, string oauth_verifier)

{

OAuthBase oauth = new OAuthBase();

Uri uri = new Uri("https://api.login.yahoo.com/oauth/v2/get_token");

string nonce = oauth.GenerateNonce();

string timeStamp = oauth.GenerateTimeStamp();

string sig = ConsumerSecret + "%26" + OauthTokenSecret;

StringBuilder sbAccessToken = new StringBuilder(uri.ToString());

sbAccessToken.AppendFormat("?oauth_consumer_key={0}&", ConsumerKey);

sbAccessToken.AppendFormat("oauth_signature_method={0}&", "PLAINTEXT"); //HMAC-SHA1

sbAccessToken.AppendFormat("oauth_signature={0}&", sig);

sbAccessToken.AppendFormat("oauth_timestamp={0}&", timeStamp);

sbAccessToken.AppendFormat("oauth_version={0}&", "1.0");

sbAccessToken.AppendFormat("oauth_token={0}&", oauth_token);

sbAccessToken.AppendFormat("oauth_nonce={0}&", nonce);

sbAccessToken.AppendFormat("oauth_verifier={0}", oauth_verifier);

//Response.Write(sbAccessToken.ToString());

//Response.End();

try

{

string returnStr = string.Empty;

string[] returnData;

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(sbAccessToken.ToString());

HttpWebResponse res = (HttpWebResponse)req.GetResponse();

StreamReader streamReader = new StreamReader(res.GetResponseStream());

returnStr = streamReader.ReadToEnd();

returnData = returnStr.Split(new Char[] { '&' });

//Response.Write(returnStr);

//Response.End();

int index;

if (returnData.Length > 0)

{

index = returnData[0].IndexOf("=");

OauthToken = returnData[0].Substring(index + 1);

index = returnData[1].IndexOf("=");

string oauth_token_secret = returnData[1].Substring(index + 1);

OauthTokenSecret = oauth_token_secret;

//index = returnData[2].IndexOf("=");

//int oauth_expires_in;

//Int32.TryParse(returnData[2].Substring(index + 1), out oauth_expires_in);

index = returnData[3].IndexOf("=");

string oauth_session_handle = returnData[3].Substring(index + 1);

OauthSessionHandle = oauth_session_handle;

//index = returnData[4].IndexOf("=");

//int oauth_authorization_expires_in;

//Int32.TryParse(returnData[4].Substring(index + 1), out oauth_authorization_expires_in);

index = returnData[5].IndexOf("=");

string xoauth_yahoo_guid = returnData[5].Substring(index + 1);

OauthYahooGuid = xoauth_yahoo_guid;

}

catch (WebException ex)

{

Response.Write(ex.Message);

}

private void RefreshToken()

{

OAuthBase oauth = new OAuthBase();

Uri uri = new Uri("https://api.login.yahoo.com/oauth/v2/get_token");

string nonce = oauth.GenerateNonce();

string timeStamp = oauth.GenerateTimeStamp();

string sig = ConsumerSecret + "%26" + OauthTokenSecret;

StringBuilder sbrefreshToken = new StringBuilder(uri.ToString());

sbrefreshToken.AppendFormat("?oauth_consumer_key={0}&", ConsumerKey);

sbrefreshToken.AppendFormat("oauth_signature_method={0}&", "PLAINTEXT"); //HMAC-SHA1

sbrefreshToken.AppendFormat("oauth_signature={0}&", sig);

sbrefreshToken.AppendFormat("oauth_timestamp={0}&", timeStamp);

sbrefreshToken.AppendFormat("oauth_version={0}&", "1.0");

sbrefreshToken.AppendFormat("oauth_token={0}&", OauthToken);

sbrefreshToken.AppendFormat("oauth_session_handle={0}&", OauthSessionHandle);

sbrefreshToken.AppendFormat("oauth_nonce={0}", nonce);

try

{

string returnStr = string.Empty;

string[] returnData;

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(sbrefreshToken.ToString());

HttpWebResponse res = (HttpWebResponse)req.GetResponse();

StreamReader streamReader = new StreamReader(res.GetResponseStream());

returnStr = streamReader.ReadToEnd();

returnData = returnStr.Split(new Char[] { '&' });

//Response.Write(returnStr);

int index;

if (returnData.Length > 0)

{

index = returnData[0].IndexOf("=");

string oauth_token = returnData[0].Substring(index + 1);

OauthToken = oauth_token;

index = returnData[1].IndexOf("=");

string oauth_token_secret = returnData[1].Substring(index + 1);

OauthTokenSecret = oauth_token_secret;

//index = returnData[2].IndexOf("=");

//int oauth_expires_in;

//Int32.TryParse(returnData[2].Substring(index + 1), out oauth_expires_in);

index = returnData[3].IndexOf("=");

string oauth_session_handle = returnData[3].Substring(index + 1);

OauthSessionHandle = oauth_session_handle;

//index = returnData[4].IndexOf("=");

//int oauth_authorization_expires_in;

//Int32.TryParse(returnData[4].Substring(index + 1), out oauth_authorization_expires_in);

index = returnData[5].IndexOf("=");

string xoauth_yahoo_guid = returnData[5].Substring(index + 1);

OauthYahooGuid = xoauth_yahoo_guid;

}

catch (WebException ex)

{

Response.Write(ex.Message);

}

private void RetriveContacts()

{

OAuthBase oauth = new OAuthBase();

Uri uri = new Uri("http://social.yahooapis.com/v1/user/" + OauthYahooGuid + "/contacts?format=XML");

string nonce = oauth.GenerateNonce();

string timeStamp = oauth.GenerateTimeStamp();

string normalizedUrl;

string normalizedRequestParameters;

string sig = oauth.GenerateSignature(uri, ConsumerKey, ConsumerSecret, OauthToken, OauthTokenSecret, "GET", timeStamp, nonce, OAuthBase.SignatureTypes.HMACSHA1, out normalizedUrl, out normalizedRequestParameters);

StringBuilder sbGetContacts = new StringBuilder(uri.ToString());

//Response.Write("URL: " + sbGetContacts.ToString());

//Response.End();

try

{

string returnStr = string.Empty;

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(sbGetContacts.ToString());

req.Method = "GET";

string authHeader = "Authorization: OAuth " +

"realm=\"yahooapis.com\"" +

",oauth_consumer_key=\"" + ConsumerKey + "\"" +

",oauth_nonce=\"" + nonce + "\"" +

",oauth_signature_method=\"HMAC-SHA1\"" +

",oauth_timestamp=\"" + timeStamp + "\"" +

",oauth_token=\"" + OauthToken + "\"" +

",oauth_version=\"1.0\"" +

",oauth_signature=\"" + HttpUtility.UrlEncode(sig) + "\"";

//Response.Write("</br>Headers: " + authHeader);

req.Headers.Add(authHeader);

HttpWebResponse res = (HttpWebResponse)req.GetResponse();

StreamReader streamReader = new StreamReader(res.GetResponseStream());

returnStr = streamReader.ReadToEnd();

XmlDocument xmldoc = new XmlDocument();

xmldoc.LoadXml(returnStr);

XmlNodeList elemList = xmldoc.DocumentElement.GetElementsByTagName("fields");

ArrayList emails = new ArrayList();

for (int i = 0; i < elemList.Count; i++)

{

if (elemList[i].ChildNodes[1].InnerText == "email")

emails.Add(elemList[i].ChildNodes[2].InnerText);

//Response.Write(elemList[i].ChildNodes[2].InnerText + "<br/>");

}

grvMyFriends.DataSource = emails;

grvMyFriends.DataBind();

}

#region error

catch (WebException ex)

{

//Response.Write(ex.Message);

Response.Write("<br/>" + ex.Message + "</br>xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");

Response.Write("<br/>length: " + ex.Source.Length.ToString());

Response.Write("<br/>stack trace: " + ex.StackTrace);

Response.Write("<br/>status: " + ex.Status.ToString());

HttpWebResponse res = (HttpWebResponse)ex.Response;

int code = Convert.ToInt32(res.StatusCode);

Response.Write("<br/>Status Code: (" + code.ToString() + ") " + res.StatusCode.ToString());

Response.Write("<br/>Status Description: " + res.StatusDescription);

if (ex.InnerException != null)

{

Response.Write("<br/>innerexception: " + ex.InnerException.Message);

}

if (ex.Source.Length > 0)

Response.Write("<br/>source: " + ex.Source.ToString());

if (res != null)

{

for (int i = 0; i < res.Headers.Count; i++)

{

Response.Write("<br/>headers: " + i.ToString() + ": " + res.Headers[i]);

}

#endregion error

}

protected void Button1_Click(object sender, EventArgs e)

{

string authorizationUrl = string.Empty;

authorizationUrl = GetRequestToken();

RedirectUserForAuthorization(authorizationUrl);

}

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