Date Selector - Silverlight Custom Control

I have created a silverlight custom control which can be used to select date in a user friendly way. It is similar to date selector control available to set birth date in facebook registration. Standard date picker control in silverlight and WPF is not user friendly and user has to perform several clicks to select a date. This control is skinable. I have open source it and hosted in codeplex. Hope to add localizations very soon. Contributions and ideas are Welcome :).

http://sldateselector.codeplex.com

Encryption in Silverlight and .NET Applications

I wanted to encrypt some sensitive data in a Silverlight application and decry pt that in the server. Sergey Barskiy's has written a good post about that. Here is the code.

Encryption functionality

using System;

using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace Encryption
{
public static class EncryptionUtility
{

///

/// Encrypt the data
///

/// String to encrypt
/// Encrypted string
public static string Encrypt(string input, string password)
{

byte[] utfData = UTF8Encoding.UTF8.GetBytes(input);
byte[] saltBytes = Encoding.UTF8.GetBytes(password);
string encryptedString = string.Empty;
using (AesManaged aes = new AesManaged())
{
Rfc2898DeriveBytes rfc = new Rfc2898DeriveBytes(password, saltBytes);

aes.BlockSize = aes.LegalBlockSizes[0].MaxSize;
aes.KeySize = aes.LegalKeySizes[0].MaxSize;
aes.Key = rfc.GetBytes(aes.KeySize / 8);
aes.IV = rfc.GetBytes(aes.BlockSize / 8);

using (ICryptoTransform encryptTransform = aes.CreateEncryptor())
{
using (MemoryStream encryptedStream = new MemoryStream())
{
using (CryptoStream encryptor =
new CryptoStream(encryptedStream, encryptTransform,CryptoStreamMode.Write))
{
encryptor.Write(utfData, 0, utfData.Length);
encryptor.Flush();
encryptor.Close();

byte[] encryptBytes = encryptedStream.ToArray();
encryptedString = Convert.ToBase64String(encryptBytes);
}
}
}
}
return encryptedString;

}

Decryption functionality

///

/// Decrypt a string
///

/// Input string in base 64 format
/// Decrypted string
public static string Decrypt(string input, string password)
{

input = input.Replace(" ","+");

byte[] encryptedBytes = Convert.FromBase64String(input);
byte[] saltBytes = Encoding.UTF8.GetBytes(password);
string decryptedString = string.Empty;
using (var aes = new AesManaged())
{
Rfc2898DeriveBytes rfc = new Rfc2898DeriveBytes(password, saltBytes);
aes.BlockSize = aes.LegalBlockSizes[0].MaxSize;
aes.KeySize = aes.LegalKeySizes[0].MaxSize;
aes.Key = rfc.GetBytes(aes.KeySize / 8);
aes.IV = rfc.GetBytes(aes.BlockSize / 8);

using (ICryptoTransform decryptTransform = aes.CreateDecryptor())
{
using (MemoryStream decryptedStream = new MemoryStream())
{
CryptoStream decryptor =
new CryptoStream(decryptedStream, decryptTransform,CryptoStreamMode.Write);
decryptor.Write(encryptedBytes, 0, encryptedBytes.Length);
decryptor.Flush();
decryptor.Close();

byte[] decryptBytes = decryptedStream.ToArray();
decryptedString =
UTF8Encoding.UTF8.GetString(decryptBytes, 0, decryptBytes.Length);
}
}
}

return decryptedString;
}
}
}

In the decrpting part I had to include the line input = input.Replace(" ","+");

It seems 64-bic encoding does not work with spaces. Plus sign will be interpreted as a space when you call the FromBase64String method.

HTML Parser - Java Library to extract html Elements

HTML Parser - HTML Parser

HTML Parser is a very cool java library which can be used to extract values in a html page.

Let's take the URL - http://www.google.ca/finance?q=BMO

Let's say we want to extract the value of the span tag - ( Mar 18 - Close.)

Here is the code

import java.io.IOException;

import java.net.MalformedURLException;

import java.net.URL;

import java.net.URLConnection;

import org.htmlparser.Node;

import org.htmlparser.Parser;

import org.htmlparser.filters.CssSelectorNodeFilter;

import org.htmlparser.util.NodeList;

import org.htmlparser.util.ParserException;

public class test {

/**

* @param args

*/

public static void main(String[] args) {

String URL = "http://www.google.ca/finance?q=BMO";

try {

URL url = new URL(URL);

URLConnection urlcon;

urlcon = url.openConnection();

Parser parser = new Parser(urlcon); // creating of HTML parser

// object

CssSelectorNodeFilter cssFilter = new CssSelectorNodeFilter(

"SPAN.nwp");

NodeList nodes = parser.parse(cssFilter); // getting nodes of

// span.nwp. Only NodeList created with one value

Node node = nodes.elementAt(0); //getting the first value of the nodes list

System.out.println(nodes.size());

String value = node.getFirstChild().getText(); //getting the value of the node

System.out.println(value);

} catch (MalformedURLException e) {

System.out.println("Malformed Exception :" + e.getMessage());

} catch (IOException e) {

e.printStackTrace();

} catch (ParserException e) {

e.printStackTrace();

}

}

}

YouTube - Sri Lanka

YouTube - Sri Lanka