Chat Con Flush Muy Parecido Al Comet - Necesito Explicacion Código PHP:
<?php
session_start();
set_time_limit(0);
if(!file_exists('log.txt'))
file_put_contents('log.txt','1'."\n<span class=\"sistema\">Sala creada el ".date('d-n-y, H:i:s',time()).'</span>',LOCK_EX);
function escribir($t){
$numlineas=5;
$ant=file('log.txt');
$indice=intval(trim($ant[0]))+1;
$ant=implode('',array_slice($ant,0,($numlineas-1)*2));
file_put_contents('log.txt',$indice."\n".$t."\n".$ant,LOCK_EX);
}
function salidaAnunciada(){
$ver=file_get_contents('log.txt');
$sal=strpos($ver,$_SESSION['nick'].' ha salido de la sala.');
if($sal!==false){
$en=strpos($ver,$_SESSION['nick'].' ha reingresado a la sala.');
$log=strpos($ver,htmlentities($_SESSION['nick'],ENT_QUOTES).' ha ingresado en la sala');
if(($en!==false && $sal<$en) || ($log!==false && $sal<$log))
return true;
return false;
}
}
if(isset($_POST['nick']) && !empty($_POST['nick'])){
$_SESSION['nick']=utf8_decode($_POST['nick']);
setcookie('nick',utf8_decode($_POST['nick']),time()+36000,'/');
escribir('<span class="sistema">'.htmlentities($_SESSION['nick'],ENT_QUOTES)." ha ingresado en la sala.</span>");
header("Location:chatino.php");
exit;
}
session_write_close();
header("Cache-control: private");
$vueltas=0;
ignore_user_abort(1);
if(isset($_POST['indice'])){
while(1){
echo "\n";
ob_flush();
flush();
if(connection_status()!=0){
if(!salidaAnunciada())
escribir('<span class="sistema">'.$_SESSION['nick'].' ha salido de la sala.</span>');
exit;
}
$renglones=file('log.txt');
$i=trim($renglones[0]);
if($_POST['indice']!=$i || empty($_SESSION['nick'])){
echo utf8_encode(implode('<br />',file('log.txt')));
ob_flush();
flush();
break;
}
if(++$vueltas<20)
sleep(3);
else
sleep(10);
}
exit;
}
if(isset($_POST['w'])){
$_SESSION['nick']=empty($_SESSION['nick'])?$_COOKIE['nick']:$_SESSION['nick'];
$ver=file_get_contents('log.txt');
$sal=strpos($ver,$_SESSION['nick'].' ha salido de la sala.');
if($sal!==false){
$en=strpos($ver,$_SESSION['nick'].' ha reingresado a la sala.');
$log=strpos($ver,htmlentities($_SESSION['nick'],ENT_QUOTES).' ha ingresado en la sala');
if( ($en===false && ($log===false)) || ($sal<$en && ($sal<$log || $log===false) ) || ($en==false && ($sal<$log || $log===false)) )
escribir('<span class="sistema">'.$_SESSION['nick'].' ha reingresado a la sala.</span>');
}
escribir('<span class="user">'.$_SESSION['nick'].'</span>: <span class="mensaje">'.htmlentities($_POST['w'],ENT_QUOTES).'</span>');
exit;
}
if(isset($_POST['out'])){
if(!salidaAnunciada())
escribir('<span class="sistema">'.$_SESSION['nick'].' ha salido de la sala.</span>');
session_start();
session_destroy();
exit;
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>CHAT</title>
<style>
body{ font-family:Verdana, Arial, Helvetica, sans-serif; font-size:10px;}
#login,#sender{ border:1px solid #000; background-color:#CCC;font-size:10px; width:50px}
#nick{font-size:10px; width:290px;border:1px solid #000;font-family:Verdana, Arial, Helvetica, sans-serif;}
#a{font-size:10px; width:380px;border:1px solid #000;font-family:Verdana, Arial, Helvetica, sans-serif;}
#mse{border:1px solid #000; width:360px; overflow:auto; padding:10px}
.user{color:#F00; font-weight:bold}
.mensaje{ color:#666}
.sistema{ color: #999}
h3{font-size:10px; padding:0;color:#999;}
</style>
<script>
function http(){
if(typeof window.XMLHttpRequest!='undefined'){
return new XMLHttpRequest();
}else{
try{
return new ActiveXObject('Microsoft.XMLHTTP');
}catch(e){
alert('Su navegador no soporta AJAX');
return false;
}
}
}
function request(url,callback,params){
var H=new http();
if(!H)return;
H.open('post',url+'?'+Math.random(),true);
H.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
H.onreadystatechange=function(){
if(H.readyState==4){
if(callback)
callback(H.responseText);
H.onreadystatechange=function(){}
H.abort();
H=null;
}
}
var p='';
for(var i in params){
p+='&'+i+'='+escape(params[i]);
}
H.send(p);
}
function $(x){return document.getElementById(x);}
onload=function(){
try{
request('chatino.php',f,{'indice':0});
}catch(e){}
}
function f(r){
try{
$('mse').innerHTML='';
var txt=r.split('<br />').reverse();
for(var i=0;txt[i];i+=2)
$('mse').innerHTML+=txt[i]+'<br />';
var indice=parseInt(r.split('<br />')[0]);
if(isNaN(indice))return;
setTimeout(function(){
request('chatino.php',f,{'indice':indice});
},10);
}catch(e){}
}
function ver(e){
var t=e.keyCode || e.wich;
if(t==13){
request('chatino.php',null,{'w':$('a').value});$('a').value='';
return false;
}
return true;
}
</script>
<?php
if(isset($_SESSION['nick']) && !empty($_SESSION['nick'])){
?>
<!--[if IE]>
<script>
onbeforeunload=function(){
request('chatino.php',null,{'out':1});
}
</script>
<![endif]-->
<?php } ?>
</head>
<body>
<?php
if(!isset($_SESSION['nick']) || empty($_SESSION['nick'])){
?>
<h3>Complete el formulario para ingresar a la sala:</h3>
<form action="chatino.php" method="post">
Nick:
<input name="nick" type="text" id="nick" />
<input id="login" type="submit" value="Enviar" />
</form>
<?php }else{?>
<div id="mse"></div>
<form>
<textarea cols="60" rows="1" id="a" onkeypress="return ver(event)"></textarea>
<input id="sender" type="button" value="Enviar" onclick="request('chatino.php',null,{'w':$('a').value});$('a').value=''" />
</form>
<?php }?>
</body>
</html> 
