The example of handler code:

<?php
//init request parameters
$userName = (isset($_GET["user_name"])) ? ($_GET["user_name"]) : "";

//Connect to users database
$db = mysql_connect('localhost','database_user_goes_here','database_password_goes_here') or die(mysql_error());
mysql_select_db('database_name',$db) or die(mysql_error());

//DB query
$sql = "SELECT * FROM users_table WHERE user_name='".$userName."'";
$result = mysql_query($sql,$db);

$userInfo= mysql_fetch_array($result);

$answer = '<profile>';
$answer .= '<name><![CDATA['.$userName.']]></name>';
$answer .= '<age>'.$userInfo['age'].'</age>';
$answer .= '<gender>'.$userInfo['gender'].'</gender>';
$answer .= '<country>'.$userInfo['country'].'</country>';
$answer .= '<city>'.$userInfo['city'].'</city>';
$answer .= '<info><![CDATA['.$userInfo['about_me'].']]></info>';
$answer .= '</profile>';

echo $answer;
exit;
?>


string login = this.Request.QueryString["name"];
string result = String.Empty;
DataTable userInfo = "SELECT FROM users WHERE name='login'";
if(userInfo.Rows.Count>0)
{
result+="<profile>";
result+="<name>"+userInfo.Rows[0]["name"]+"</name>";
result+="<gender>"+userInfo.Rows[0]["gender"]+"</gender>";
result+="<age>"+userInfo.Rows[0]["age"]+"</age>";
result+="<info><![CDATA["+userInfo.Rows[0]["info"]+"]]></info>";
result+="</profile>";
}
Response.Clear();
Response.Write(result);
Response.End();