Website is being attacked php way to prevent it

Recently the site is often attacked, and later thought of a way to use php tutorial to prevent the site from being attacked. Here is my code, the code is not the best, according to their needs to do, here's my code.
/ *
* Website ip attack code (anti-ip attack code website) 2010-11-20, ver2.0
* mydalle.com anti-refresh mechanism
* design by www.jzread.com
* /

<? php
// Query forbid ip
$ ip = $ _ server ['remote_addr'];
$ fileht = ". htaccess2";
if (! file_exists ($ fileht)) file_put_contents ($ fileht, "");
$ filehtarr = @ file ($ fileht);
if (in_array ($ ip. "rn", $ filehtarr)) die ("warning:". "<br>". "your ip address are forbided by mydalle.com anti-refresh mechanism, if you have any question pls emill to shop@mydalle.com! <br> (mydalle.com anti-refresh mechanism is to enable users to have a good shipping services, but there maybe some inevitable network problems in your ip address, so that you can mail to us to solve ) ");

// join ban ip
$ time = time ();
$ fileforbid = "log / forbidchk.dat";
if (file_exists ($ fileforbid))
{if ($ time-filemtime ($ fileforbid)> 30) unlink ($ fileforbid);
else {
$ fileforbidarr = @ file ($ fileforbid);
if ($ ip == substr ($ fileforbidarr [0], 0, strlen ($ ip)))
{
if ($ time-substr ($ fileforbidarr [1], 0, strlen ($ time))> 120) unlink ($ fileforbid);
elseif ($ fileforbidarr [2]> 120) {file_put_contents ($ fileht, $ ip. "rn", file_append); unlink ($ fileforbid);}
else {$ fileforbidarr [2] ++; file_put_contents ($ fileforbid, $ fileforbidarr);}
}
}
}
// anti-refresh
$ str = "";
$ file = "log / ipdate.dat";
if (! file_exists ("log") &&! is_dir ("log")) mkdir ("log", 0777);
if (! file_exists ($ file)) file_put_contents ($ file, "");
$ allowtime = 60; / / anti-refresh time
$ allownum = 5; / / anti-refresh the number
$ uri = $ _ server ['request_uri'];
$ checkip = md5 ($ ip);
$ checkuri = md5 ($ uri);
$ yesno = true;
$ ipdate = @ file ($ file);
foreach ($ ipdate as $ k => $ v)
{$ iptem = substr ($ v, 0,32);
$ uritem = substr ($ v, 32,32);
$ timetem = substr ($ v, 64,10);
$ numtem = substr ($ v, 74);
if ($ time- $ timetem <$ allowtime) {
if ($ iptem! = $ checkip) $ str. = $ v;
else {
$ yesno = false;
if ($ uritem! = $ checkuri) $ str. = $ iptem. $ checkuri. $ time. "1rn";
elseif ($ numtem <$ allownum) $ str. = $ iptem. $ uritem. $ timetem. ($ numtem + 1). "rn";
else
{
if (! file_exists ($ fileforbid)) {$ addforbidarr = array ($ ip. "rn", time (). "rn", 1); file_put_contents ($ fileforbid, $ addforbidarr);}
file_put_contents ("log / forbided_ip.log", $ ip. "-". date ("ymd h: i: s", time ()). "-". $ uri. "rn", file_append);
$ timepass = $ timetem + $ allowtime- $ time;
die ("warning:". "<br>". "pls do not refresh too frequently, and wait for". $ timepass. "seconds to continue, if not your ip address will be forbided automatic by mydalle.com anti- refresh mechanism! <br> (mydalle.com anti-refresh mechanism is to enable users to have a good shipping services, but there maybe some inevitable network problems in your ip address, so that you can mail to us to solve.) ") ;
}
}
}
}
if ($ yesno) $ str. = $ checkip. $ checkuri. $ time. "1rn";
file_put_contents ($ file, $ str);
?>