值得分享的php+ajax实时聊天室

<?php
header('content-type:text/html;charset=utf-8');
//显示在线用户
$disonline = 1;
//新登陆时显示最近内容的条数(默认为30条)
$leastnum = 30;
//默认的房间名(默认是每天换一个文件)，如果去掉d，则是每月换一个文件
$room = date("Y-m-d");
//房间保存路径,必须仿quot;/"结尾,可以丿quot;../"，等
$roomdir = "rooms/";
//编码方式
$charset = "UTF-8";
//客户端最大显示内容条数(建议不要太大)
$maxdisplay = 300;
//语言包
$lang = array(
//聊天室描述
"description"=>"聊天室.", 
//聊天室标题
"title"=>"Welcome...!",
//第一个到聊天室的欢迎
"firstone"=>"<span style='font-size:16px;color:blue;'>Welcome...!</span>", 
//当信息有禁止内容时显示
"ban" => array(),
//关键字
"keywords"=>"Welcome...!",
//发言提示
"hereyourwords" => "在这里发言!"
);

$touchs = 10;
$title = $lang["title"];
$earlier = 10;
$description = $lang["description"];
$origroom = $room;
$least = ($_GET["dis"])?intval($_GET["dis"]):$leastnum;
if ($_GET["room"]) $room = $_GET["room"];
$room = checkfilename($room);
if (!$room) $room = $origroom;
$filename = $roomdir.$room.".dat.php";
$datafile = $roomdir.$room.".php";

if (!is_dir($roomdir)) {
 @mkdir($roomdir, 0777) or exit('no this dir.');
}
if(file_exists($filename)){
 if ((int)filemtime($filename) + 1800 < time()) {
 unlink($filename);
 }
}

if (!file_exists($filename)) @file_put_contents($filename,'<?php die();?>'."\n".time()."|".$lang["firstone"]."\n");
if (!file_exists($datafile)) @file_put_contents($datafile,'<?php die();?>'."\n");
$action = $_GET["action"];

if (!function_exists("file_get_contents"))
{
 function file_get_contents($path)
 {
 if (!file_exists($path)) return false;
 $fp=@fopen($path,"r");
 $all=fread($fp,filesize($path));
 fclose($fp);
 return $all;
 }
}

if (!function_exists("file_put_contents"))
{
 function file_put_contents($path,$val)
 {
 $fp=@fopen($path,"w");
 fputs($fp,$val);
 fclose($fp);
 return true;
 }
}

function checkfilename($file)
{
 if (!$file) return "";
 $file = trim($file);
 $a = substr($file,-1);
 $file = eregi_replace("^[.\\\/]*","",$file);
 $file = eregi_replace("[.\\\/]*$","",$file);
 $arr = array("../","./","/","\\","..\\",".\\");
 $file = str_replace($arr,"",$file);
 return $file;
}

function get_ip()
{
 global $_SERVER;
 if ($_SERVER)
 {
 if ( $_SERVER[HTTP_X_FORWARDED_FOR] )
 $realip = $_SERVER["HTTP_X_FORWARDED_FOR"];
 else if ( $_SERVER["HTTP_CLIENT_ip"] )
 $realip = $_SERVER["HTTP_CLIENT_ip"];
 else
 $realip = $_SERVER["REMOTE_ADDR"];
 }
 else
 {
 if ( getenv( 'HTTP_X_FORWARDED_FOR' ) )
 $realip = getenv( 'HTTP_X_FORWARDED_FOR' );
 else if ( getenv( 'HTTP_CLIENT_ip' ) ) 
 $realip = getenv( 'HTTP_CLIENT_ip' );
 else
 $realip = getenv( 'REMOTE_ADDR' );
 }
 return $realip;
}

function array2json($arr)
{
 if (function_exists('json_encode')) return json_encode($arr);
 $keys = array_keys($arr);
 $isarr = true;
 $json = "";
 for($i=0;$i<count($keys);$i++)
 {
 if ($keys[$i] !== $i)
 {
 $isarr = false;
 break;
 }
 }
 $json = $space;
 $json.= ($isarr)?"[":"{";
 for($i=0;$i<count($keys);$i++)
 {
 if ($i!=0) $json.= ",";
 $item = $arr[$keys[$i]];
 $json.=($isarr)?"":$keys[$i].':';
 if (is_array($item))
 $json.=array2json($item);
 else if (is_string($item))
 $json.='"'.str_replace(array("\r","\n"),"",$item).'"';
 else $json.=$item;
 }
 $json.= ($isarr)?"]":"}";
 return $json;
}

if ($action == "write")
{
 $color = $_GET['color'];
 if (!eregi("[0-9a-fA-F]{6}",$color) || $color == "#000000") $color = "";
 $color = "#".$color;
 $size = intval($_GET["size"]);
 $arr = @file("php://input");
 $name = str_replace(array("\n","\r"),"",$arr[0]);
 $ip = get_ip();
 if ($disonline)
 {
 $onlines = @file_get_contents($datafile);
 $s1 = "|{$name}|{$ip}|";
 if (strpos($onlines,$s1) === false)
 {
 if (strpos($onlines,"|".$name."|") === false)
 {
 $fp = @fopen($datafile,"a+");
 if ($fp)
 {
 if (@flock($fp, LOCK_EX))
 {
 @fputs($fp,time()."|".time().$s1."\n");
 @flock($fp, LOCK_UN);
 }
 @fclose($fp);
 }
 }
 else
 {
 echo "NAME";
 die();
 }
 }
 }

 $s = "";
 $style = "";
 $font = $_GET["font"];
 if ($font == "songti") $font = "宋体";
 else if ($font == "heiti") $font = "黑体";
 else if ($font == "kaiti") $font = "楷体_GB2312";
 else $font = "";
 $style .= (!$font)?"":"font-family:".$font.";";
 $style .= (!$_GET["bold"])?"":"font-weight:bold;";
 $style .= (!$color || $color == "#")?"":"color:{$color};";
 $style .= (!$size || $size == "16")?"":"font-size:{$size}px;";
 $t = time();
 for($i = 1;$i<count($arr);$i++)
 {
 $content = $arr[$i];
 $content = str_replace(array("\n","\r"),"",$content);
 if ($content == "") continue;
 $content = preg_replace("!<img\s+(.*?)/>!i", "[img $1/]", $content);
 $content = str_replace(array('<', '>'), array('<', '>'), $content);
 $content = preg_replace("!\[img (.*?)/\]!i", "<img $1/>", $content);
 $content = str_replace($lang['ban'], '', $content);
 $content = ($style)?"<span style='{$style}'>{$content}</span>":$content;
 $ubbarray = array('[:ani_wink:]',
 '[:big_eyes:]',
 '[:cool:]',
 '[:cry:]',
 '[:eye_roll:]',
 '[:grin:]',
 '[:happy:]',
 '[:not_impressed:]',
 '[:smile:]',
 '[:smile_eyes:]',
 '[:stickout:]',
 '[:straight:]',
 '[:surprised:]',
 '[:unhappy:]',
 '[:wink:]');
 $content = str_replace($ubbarray, 
 array('<img src="smilies/ani_wink.gif" />',
 '<img src="smilies/big_eyes.gif" />',
 '<img src="smilies/cool.gif" />',
 '<img src="smilies/cry.gif" />',
 '<img src="smilies/eye_roll.gif" />',
 '<img src="smilies/grin.gif" />',
 '<img src="smilies/happy.gif" />',
 '<img src="smilies/not_impressed.gif" />',
 '<img src="smilies/smile.gif" />',
 '<img src="smilies/smile_eyes.gif" />',
 '<img src="smilies/stickout.gif" />',
 '<img src="smilies/straight.gif" />',
 '<img src="smilies/surprised.gif" />',
 '<img src="smilies/unhappy.gif" />',
 '<img src="smilies/wink.gif" />'), 
 $content);
 $s.= $t."|".$name.":".$content."\n";
 }
 if (!$name) die("No Name!!");
 if (!$s) die("No Content!!");
 $fp = @fopen($filename,"a+");
 if (!$fp) die("repeat");
 if (@flock($fp, LOCK_EX))
 {
 @fputs($fp,$s);
 @flock($fp, LOCK_UN);
 }
 else die("repeat");
 @fclose($fp);
 echo "OK";
}
else if (trim($action) == "read")
{
 if (get_magic_quotes_runtime()) {
 set_magic_quotes_runtime(0);
 }
 $first = $_GET["first"];
 $lastmod = intval($_GET["lastmod"]);
 $alastmod = @filemtime($filename);
 $name = file_get_contents("php://input");
 $name = str_replace("\n","",$name);
 $ip = get_ip();
 $json = array();
 $json["lastmod"] = $alastmod;
 $item = array();
 $newonline = array();
 $offline = array();

 $lines = @file($filename);
 if ($alastmod > $lastmod && !$first)
 {
 foreach($lines as $l)
 {
 $item2 = array();
 $l = str_replace(array("\n","\r"),"",$l);
 if (strpos($l,"|") === false) continue;
 $arr = explode("|",$l);
 $t = intval($arr[0]);
 if ($t > $lastmod)
 {
 $item2["time"] = date("H:i:s",$t);
 $item2["word"] = stripslashes($arr[1]);
 $item[] = $item2;
 }
 }
 }
 else if ($first)
 {
 $item = array();
 $total = count($lines);
 for($i=$total-1;$i>=$total-$least;$i--)
 {
 if ($i<=0) break;
 $item2 = array();
 $l = str_replace(array("\n","\r"),"",$lines[$i]);
 if (strpos($l,"|") === false) continue;
 $arr = explode("|",$l);
 $t = intval($arr[0]);
 $item2["time"] = (date("m-d",time()) == date("m-d",$t))?date("H:i:s",$t):date("m-d H:i",$t);
 $item2["word"] = stripslashes($arr[1]);
 $item[] = $item2;
 }
 $item = array_reverse($item);
 }

 $s = "";
 $nt = time();
 $onlines = array();
 if($disonline)
 {
 $users = @file($datafile);
 foreach($users as $l)
 {
 $l = str_replace(array("\r","\n"),"",$l);
 if (strpos($l,"|") === false)
 {
 $s.=$l."\n";
 continue;
 }
 $arr = explode("|",$l);
 if ($nt - intval($arr[1]) < $touchs*2+1)
 {
 if (trim($name) == trim($arr[2]))
 {
 $s.= $arr[0]."|".time()."|".$name."|".get_ip()."|\n";
 }
 else $s.=$l."\n";
 $onlines [] = $arr[2];
 }
 }
 @file_put_contents($datafile,$s);
 $json["onlines"] = $onlines;
 }
 $json["lines"] = $item;
 echo array2json($json);
 if (!get_magic_quotes_runtime()) {
 set_magic_quotes_runtime(1);
 }
}
else
{
?>