PHP security filter function sample code

//安全过滤输入[jb] 
function check_str($string, $isurl = false) 
{ 
$string = preg_replace('/[\\x00-\\x08\\x0B\\x0C\\x0E-\\x1F]/','',$string); 
$string = str_replace(array("\0","%00","\r"),'',$string); 
empty($isurl) && $string = preg_replace("/&(?!(#[0-9]+|[a-z]+);)/si",'&',$string); 
$string = str_replace(array("%3C",&#39;<&#39;),&#39;<&#39;,$string); 
$string = str_replace(array("%3E",&#39;>&#39;),&#39;>&#39;,$string); 
$string = str_replace(array(&#39;"&#39;,"&#39;","\t",&#39; &#39;),array(&#39;“&#39;,&#39;‘&#39;,&#39; &#39;,&#39; &#39;),$string); 
return trim($string); 
}

/**
* 安全过滤类-过滤javascript,css,iframes,object等不安全参数 过滤级别高
*  Controller中使用方法：$this->controller->fliter_script($value)
* @param  string $value 需要过滤的值
* @return string
*/
function fliter_script($value) {
$value = preg_replace("/(javascript:)?on(click|load|key|mouse|error|abort|move|unload|change|dblclick|move|reset|resize|submit)/i","&111n\\2",$value);
$value = preg_replace("/(.*?)<\/script>/si","",$value);
$value = preg_replace("/(.*?)<\/iframe>/si","",$value);
$value = preg_replace ("//iesU", &#39;&#39;, $value);
return $value;
}
/**
* 安全过滤类-过滤HTML标签
*  Controller中使用方法：$this->controller->fliter_html($value)
* @param  string $value 需要过滤的值
* @return string
*/
function fliter_html($value) {
if (function_exists(&#39;htmlspecialchars&#39;)) return htmlspecialchars($value);
return str_replace(array("&", &#39;"&#39;, "&#39;", "<", ">"), array("&", "\"", "&#39;", "<", ">"), $value);
}
/**
* 安全过滤类-对进入的数据加下划线 防止SQL注入
*  Controller中使用方法：$this->controller->fliter_sql($value)
* @param  string $value 需要过滤的值
* @return string
*/
function fliter_sql($value) {
$sql = array("select", &#39;insert&#39;, "update", "delete", "\&#39;", "\/\*", 
     "\.\.\/", "\.\/", "union", "into", "load_file", "outfile");
$sql_re = array("","","","","","","","","","","","");
return str_replace($sql, $sql_re, $value);
}
/**
* 安全过滤类-通用数据过滤
*  Controller中使用方法：$this->controller->fliter_escape($value)
* @param string $value 需要过滤的变量
* @return string|array
*/
function fliter_escape($value) {
if (is_array($value)) {
  foreach ($value as $k => $v) {
   $value[$k] = self::fliter_str($v);
  }
} else {
  $value = self::fliter_str($value);
}
return $value;
}
/**
* 安全过滤类-字符串过滤 过滤特殊有危害字符
*  Controller中使用方法：$this->controller->fliter_str($value)
* @param  string $value 需要过滤的值
* @return string
*/
function fliter_str($value) {
$badstr = array("\0", "%00", "\r", &#39;&&#39;, &#39; &#39;, &#39;"&#39;, "&#39;", "<", ">", "   ", "%3C", "%3E");
$newstr = array(&#39;&#39;, &#39;&#39;, &#39;&#39;, &#39;&&#39;, &#39; &#39;, &#39;"&#39;, &#39;&#39;&#39;, "<", ">", "   ", "<", ">");
$value  = str_replace($badstr, $newstr, $value);
$value  = preg_replace(&#39;/&((#(\d{3,5}|x[a-fA-F0-9]{4}));)/&#39;, &#39;&\\1&#39;, $value);
return $value;
}
/**
* 私有路劲安全转化
*  Controller中使用方法：$this->controller->filter_dir($fileName)
* @param string $fileName
* @return string
*/
function filter_dir($fileName) {
$tmpname = strtolower($fileName);
$temp = array(&#39;:/&#39;,"\0", "..");
if (str_replace($temp, &#39;&#39;, $tmpname) !== $tmpname) {
  return false;
}
return $fileName;
}
/**
* 过滤目录
*  Controller中使用方法：$this->controller->filter_path($path)
* @param string $path
* @return array
*/
public function filter_path($path) {
$path = str_replace(array("&#39;",&#39;#&#39;,&#39;=&#39;,&#39;`&#39;,&#39;$&#39;,&#39;%&#39;,&#39;&&#39;,&#39;;&#39;), &#39;&#39;, $path);
return rtrim(preg_replace(&#39;/(\/){2,}|(\\\){1,}/&#39;, &#39;/&#39;, $path), &#39;/&#39;);
}
/**
* 过滤PHP标签
*  Controller中使用方法：$this->controller->filter_phptag($string)
* @param string $string
* @return string
*/
public function filter_phptag($string) {
return str_replace(array(&#39;&#39;), array(&#39;<?&#39;, &#39;?>&#39;), $string);
}
/**
* 安全过滤类-返回函数
*  Controller中使用方法：$this->controller->str_out($value)
* @param  string $value 需要过滤的值
* @return string
*/
public function str_out($value) {
$badstr = array("<", ">", "%3C", "%3E");
$newstr = array("<", ">", "<", ">");
$value  = str_replace($newstr, $badstr, $value);
return stripslashes($value); //下划线
}