php中过滤非法字符的具体实现

<?php
class sqlsafe {
private $getfilter = "‘|(and|or)\\b.+?(>|<|=|in|like)|\\/\\*.+?\\*\\/|<\\s*script\\b|\\bEXEC\\b|UNION.+?SELECT|UPDATE.+?SET|INSERT\\s+INTO.+?VALUES|(SELECT|DELETE).+?FROM|(CREATE|ALTER|DROP|TRUNCATE)\\s+(TABLE|DATABASE)";
private $postfilter = "\\b(and|or)\\b.{1,6}?(=|>|<|\\bin\\b|\\blike\\b)|\\/\\*.+?\\*\\/|<\\s*script\\b|\\bEXEC\\b|UNION.+?SELECT|UPDATE.+?SET|INSERT\\s+INTO.+?VALUES|(SELECT|DELETE).+?FROM|(CREATE|ALTER|DROP|TRUNCATE)\\s+(TABLE|DATABASE)";
private $cookiefilter = "\\b(and|or)\\b.{1,6}?(=|>|<|\\bin\\b|\\blike\\b)|\\/\\*.+?\\*\\/|<\\s*script\\b|\\bEXEC\\b|UNION.+?SELECT|UPDATE.+?SET|INSERT\\s+INTO.+?VALUES|(SELECT|DELETE).+?FROM|(CREATE|ALTER|DROP|TRUNCATE)\\s+(TABLE|DATABASE)";
/**
* 构造函数
*/
public function __construct() {
foreach($_GET as $key=>$value){$this->stopattack($key,$value,$this->getfilter);}
foreach($_POST as $key=>$value){$this->stopattack($key,$value,$this->postfilter);}
foreach($_COOKIE as $key=>$value){$this->stopattack($key,$value,$this->cookiefilter);}
}
/**
* 参数检查并写日志
*/
public function stopattack($StrFiltKey, $StrFiltValue, $ArrFiltReq){
if(is_array($StrFiltValue))$StrFiltValue = implode($StrFiltValue);
if (preg_match("/".$ArrFiltReq."/is",$StrFiltValue) == 1){
$this->writeslog($_SERVER["REMOTE_ADDR"]." ".strftime("%Y-%m-%d %H:%M:%S")." ".$_SERVER["PHP_SELF"]." ".$_SERVER["REQUEST_METHOD"]." ".$StrFiltKey." ".$StrFiltValue);
showmsg(‘您提交的参数非法,系统已记录您的本次操作！‘,‘‘,0,1);
}
}
/**
* SQL注入日志
*/
public function writeslog($log){
$log_path = CACHE_PATH.‘logs‘.DIRECTORY_SEPARATOR.‘sql_log.txt‘;
$ts = fopen($log_path,"a+");
fputs($ts,$log."\r\n");
fclose($ts);
}
}
?>