یک کد json

 if ($userId = authenticateUser($db, $username, $password))
		{

	// providerId and requestId is Id of  a friend pair,
	// providerId is the Id of making first friend request
	// requestId is the Id of the friend approved the friend request made by providerId

	// fetching friends,
	// left join expression is a bit different,
        //		it is required to fetch the friend, not the users itself

			$sql = "select u.Id, u.username, (NOW()-u.authenticationTime) 
as authenticateTimeDifference, u.IP,u.authenticationTime,u.wall,

f.providerId, f.requestId, f.status, u.port
							from friends f
							left join users u on


u.Id = if ( f.providerId = ".$userId.", f.requestId, f.providerId )

where (f.providerId = ".$userId." and f.status=".USER_APPROVED.")  or

 f.requestId = ".$userId." ";

	$sqlmessage = "SELECT m.id, m.fromuid, m.touid, m.sentdt, m.read, m.readdt, 
m.messagetext, u.username from messages m \n"
    . "left join users u on u.Id = m.fromuid WHERE `touid` = ".$userId." AND `read` = 0
 LIMIT 0, 30 ";


			if ($result = $db->query($sql))
			{
					$out .= "<data>";
					$out .= "<user userKey='".$userId."' />";
					while ($row = $db->fetchObject($result))
					{
						$status = "offline";
						if (((int)$row->status) == USER_UNAPPROVED)
						{
							$status = "unApproved";
						}
						else if (((int)$row->authenticateTimeDifference) < TIME_INTERVAL_FOR_USER_STATUS)
						{
							$status = "online";

						}
						$out .= "<friend  username = '".$row->username."'  status='".$status."' IP='".$row->IP."' userKey = '".$row->Id."'  port='".$row->port."' authenticationTime ='".$row->authenticationTime."'  wall='".$row->wall."' />";

												// to increase security, we need to change userKey periodically and pay more attention
												// receiving message and sending message

					}
						if ($resultmessage = $db->query($sqlmessage))
							{
							while ($rowmessage = $db->fetchObject($resultmessage))
								{
								$out .= "<message  from='".$rowmessage->username."'  sendt='".$rowmessage->sentdt."' text='".$rowmessage->messagetext."' />";
								$sqlendmsg = "UPDATE `messages` SET `read` = 1, `readdt` = '".DATE("Y-m-d H:i")."' WHERE `messages`.`id` = ".$rowmessage->id.";";
								$db->query($sqlendmsg);
								}
							}
					$out .= "</data>";
			}
			else
			{
				$out = FAILED;
			}
		}
		else
		{
				// exit application if not authenticated user
				$out = FAILED;
		}