chat.class.php

<?php
// load error handling module
//require_once('error_handler.php');

// class that contains server-side chat functionality
class Chat
{
  // database handler
  private $mMysqli;  
  
  // constructor opens database connection
  function __construct() 
  {   
    // connect to the database	
//error_log( "Log: " . $_SERVER["SERVER_NAME"] );
	//if( stristr( $_SERVER["SERVER_NAME"], "localhost" ) == FALSE )
	//	$this->mMysqli = new mysqli("racoredb.cnqhi42h5bsx.eu-west-1.rds.amazonaws.com", "immensegames", "74747474", 'RACore');  //	Live
	//else
		$this->mMysqli = new mysqli("localhost", "Scott", "74747474", 'RACore');  	//	Home/dev
  }
 
  // destructor closes database connection  
  public function __destruct() 
  {
    $this->mMysqli->close();
  }

  /*
   The postMessages method inserts a message into the database
   - $name represents the name of the user that posted the message
   - $messsage is the posted message
   - $color contains the color chosen by the user
  */ 
  public function postMessage($name, $message)
  {  
    // escape the variable data for safely adding them to the database
    $name = $this->mMysqli->real_escape_string($name);
    $message = $this->mMysqli->real_escape_string($message);
	//$message = preg_replace('/[^(\x20-\x7F)]*/','', $message );
	
	// build the SQL query that adds a new message to the server
	$query = "INSERT INTO Chat(Submitted, User, Message)
			  VALUES (NOW(), \"$name\", \"$message\" )";
	
	//error_log( $query );
	
	// execute the SQL query
	$result = $this->mMysqli->query($query);
  }

  /*
   The retrieveNewMessages method retrieves the new messages that have 
   been posted to the server. 
   - the $id parameter is sent by the client and it
   represents the id of the last message received by the client. Messages
   more recent by $id will be fetched from the database and returned to
   the client in XML format.
  */
  public function retrieveNewMessages($id=0, $maxMessages=50) 
  {
    // escape the variable data 
    $id = $this->mMysqli->real_escape_string($id);
	
    // compose the SQL query that retrieves new messages
    if($id>0)
    {
		// retrieve messages newer than $id
		$query = "
			SELECT ch.ID, ua.User, ua.RAPoints, ua.Motto, Message, UNIX_TIMESTAMP(ch.Submitted) AS Submitted
			FROM Chat AS ch
			LEFT JOIN UserAccounts AS ua ON ua.User = ch.User
			WHERE ch.ID > $id
			ORDER BY ch.ID ASC
			LIMIT 50";
    }
    else
    {
		// on the first load only retrieve the last $maxMessages messages from server
		$query = "
			SELECT ChatHistory.ID, ua.User, ua.RAPoints, ua.Motto, Message, Submitted
			FROM (
					SELECT ID, User, Message, UNIX_TIMESTAMP(Submitted) AS Submitted
					FROM Chat 
					ORDER BY ID DESC 
					LIMIT $maxMessages
					) AS ChatHistory
			LEFT JOIN UserAccounts AS ua ON ua.User = ChatHistory.User
					
			ORDER BY ChatHistory.ID ASC ";
    }
	
    // execute the query
    $result = $this->mMysqli->query($query);  
	
	//if( ( $this->mMysqli->error !== NULL ) && ( strlen( $this->mMysqli->error ) > 2 ) )
	//error_log( $query );
	
    // build the XML response
    $response = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>';
    $response .= '<response>';
	
    // output the clear flag
    $response .= "<clear>false</clear>";
	
    // check to see if we have any results
    if($result && $result->num_rows)
    {      
      // loop through all the fetched messages to build the result message
      while ($row = $result->fetch_array(MYSQLI_ASSOC))
      {
        $id 		= $row['ID'];
        $user 		= htmlspecialchars ($row['User']);
        $time 		= htmlspecialchars ($row['Submitted']); 
        $userPoints = htmlspecialchars ($row['RAPoints']);
        $userMotto 	= htmlspecialchars ($row['Motto']);
        $message 	= htmlspecialchars ($row['Message']);
		
        $response .= "<id>$id</id>
                     <time>$time</time>
                     <name><![CDATA[$user]]></name>
                     <points>$userPoints</points>
                     <motto><![CDATA[$userMotto]]></motto>
                     <message><![CDATA[$message]]></message>";
      } 
	  
	  //error_log( $response );
	  
      // close the database connection as soon as possible
      $result->close();
    }
    
    // finish the XML response and return it
    $response = $response . '</response>';
    return $response;    
  }
  
}
?>