Imitate the Hanshunping teacher to do the web chat system, the great God help to see what the problem

Imitate the Hanshunping teacher to do the web chat system, the great God help see what the problem
This post was last edited by Alakey on 2014-01-18 22:52:59

chatroom.php******



 Accept the user name passed by open
$username =$_get[' username '];
$username =trim ($username);
Session_Start ();
$loginuser =$_session[' Loginuser '];
?>

 
  
 





 
  
 
   

 
   

 
   
Web chat room ( 
     being and 
     chatting)
 
   

 
   
 
   

 
   

 
   
 
   

 
   
 
   


  
 



getmessagecontroller.php********


 Require_once ' MessageService.class.php ';
Header ("Content-type:text/xml;charset=utf-8");
Header ("Cache-control:no-cache"):
$getter =$_post[' getter '];
$sender =$_post[' sender '];
 
$messageService =new Messageservice ();

$messageList = $messageService->getmessage ($getter, $sender);
 
Echo $messageList;

?>

messageservice.class.php********


 
Require_once ' SqlHelper.class.php ';
Class messageservice{

function AddMessage ($sender, $getter, $con) {
$sql = "INSERT INTO messages (Sender,getter,content,sendtime) VALUES (' $sender ', ' $getter ', ' $con ', Now ())";
$sqlHelper =new sqlHelper ();
Return $sqlHelper->execute_dml ($sql);
}

function GetMessage ($getter, $sender) {
 
$sql = "SELECT * from messages where getter= ' $getter ' and sender= ' $sender ' and isget=0 ';
    
$sqlHelper =new sqlHelper ();

$array = $sqlHelper->execute_dql2 ($sql);
$messageInfo = "
 
  
   
 ";
   
for ($i =0; $i<>
   
$row = $array [$i];
   
$messageInfo. = " 
   
    {$row [' id ']}
    { 
   
    $row [' Sender ']}
    
   
    {$row [' getter ']}
    
   
    {$row [' Conte NT ']}
    
   
    {$row [' Sendtime ']} 
   ";
 
 
 
 
   
}
   
$messageInfo. = "
  
 ";
$sqlHelper->close_connect ();
return $messageInfo;
}

}
?>

The great God help to see where the problem is?
------to solve the idea----------------------
Didn't look carefully. Single sentence: Session_Start ();
Because there is an HTML tag in front of the output, there will definitely be "headers already sent" error, right?

You didn't tell me what was wrong with you.
------to solve the idea----------------------
It's important to write robust code.

....
if (myxmlhttprequest.status==200) {
  var mesres=myxmlhttprequest.responsexml;
  if (Mesres.xml = = ") {//If it is not an XML object
    alert (myxmlhttprequest.responsetext);//See what's returned
    Return
  }
....

------to solve the idea----------------------
This estimate is also a appearance bar, the performance is relatively poor.
Chat rooms, using websockeet or comet,
Second, you don't have to use a database, Redis or file storage to
------to solve the idea----------------------
Header ("Cache-control:no-cache"):
This kind of mistake, the hint should be obvious.

