PHP uses str_replace() function to prevent injection

str_replace()函数的使用就是用来替换指定字符了，那么我们正好可以利用它这一点来过滤敏感字符以太到防注入的效果，下面我来给大家总结了一些方法，给大家分享一下。

PHP各种过滤字符函数

代码如下

复制代码

   /**
* 安全过滤函数
*
* @param $string
* @return string
*/
function safe_replace($string) {
$string = str_replace('%20','',$string);
$string = str_replace('%27','',$string);
$string = str_replace('%2527','',$string);
$string = str_replace('*','',$string);
$string = str_replace('"','"',$string);
$string = str_replace("'",'',$string);
$string = str_replace('"','',$string);
$string = str_replace(';','',$string);
$string = str_replace('<','<',$string);
$string = str_replace('>','>',$string);
    $string = str_replace("{",'',$string);
    $string = str_replace('}','',$string);
    $string = str_replace('','',$string);
    return $string;
    }
    ?>

    /**
* 返回经addslashes处理过的字符串或数组
* @param $string 需要处理的字符串或数组
* @return mixed
*/
function new_addslashes($string) {
if(!is_array($string)) return addslashes($string);
foreach($string as $key => $val) $string[$key] = new_addslashes($val);
    return $string;
    }
    ?>

    //对请求的字符串进行安全处理
/*
$safestep
0 为不处理，
1 为禁止不安全HTML内容(javascript等)，
2 完全禁止HTML内容，并替换部份不安全字符串（如：eval(、union、CONCAT(、--、等）
*/
function StringSafe($str, $safestep=-1){
$safestep = ($safestep > -1) ? $safestep : 1;
    if($safestep == 1){
    $str = preg_replace("#script:#i", "ｓｃｒｉｐｔ：", $str);
    $str = preg_replace("#<[/]{0,1}(link|meta|ifr|fra|scr)[^>]*>#isU", '', $str);
    $str = preg_replace("#[ ]{1,}#", ' ', $str);
    return $str;
    }else if($safestep == 2){
    $str = addslashes(htmlspecialchars(stripslashes($str)));
    $str = preg_replace("#eval#i", 'ｅｖａｌ', $str);
    $str = preg_replace("#union#i", 'ｕｎｉｏｎ', $str);
    $str = preg_replace("#concat#i", 'ｃｏｎｃａｔ', $str);
    $str = preg_replace("#--#", '－－', $str);
    $str = preg_replace("#[ ]{1,}#", ' ', $str);
    return $str;
    }else{
    return $str;
    }
    }
    ?>

/**
+------------------------------------------------- ----------
* Output safe html, used to filter dangerous codes
+------------------------------------------------- ----------
* @access public
+------------------------------------------------- ----------
* @param string $text The string to be processed
* @param mixed $tags list of allowed tags, such as table|td|th|td
+------------------------------------------------- ----------
* @return string
+------------------------------------------------- ----------
*/
        static public function safeHtml($text, $tags = null)
          {
            $text = trim($text);
//Completely filter comments
                $text = preg_replace('//','',$text);
//Completely filter dynamic code
$ Text = Preg_replace ('/& LT;? |?'. '& GT;/', '', $ Text);
//Completely filter js
                $text = preg_replace('//','',$text);
              $text = str_replace('[','[',$text);
               $text = str_replace(']',']',$text);
             $text = str_replace('|','|',$text);
//Filter newlines
               $text = preg_replace('/ ? /','',$text);
                  //br
                $text = preg_replace('//i','[br]',$text);
               $text = preg_replace('/([br]s*){10,}/i','[br]',$text);
//Filter dangerous attributes, such as: filter on event lang js
while(preg_match('/(<[^><]+)(lang|on|action|background|codebase|dynsrc|lowsrc)[^><]+/i',$text,$mat )){
                   $text=str_replace($mat[0],$mat[1],$text);
           }
while(preg_match('/(<[^><]+)(window.|javascript:|js:|about:|file:|document.|vbs:|cookie)([^><] *)/i',$text,$mat)){
$text=str_replace($mat[0],$mat[1].$mat[3],$text);
           }
                  if( empty($allowTags) ) { $allowTags = self::$htmlTags['allow']; }
//Allowed HTML tags
                 $text = preg_replace('/<('.$allowTags.')( [^><[]]*)>/i','[12]',$text);
//Filter excess html
If ( empty($banTag) ) { $banTag = self::$htmlTags['ban']; }
                 $text = preg_replace('/<]*>/i','',$text);
//Filter legal html tags
while(preg_match('/<([a-z]+)[^><[]]*>[^><]*/i',$text,$mat)) {
               $text=str_replace($mat[0],str_replace('>',']',str_replace('<','[',$mat[0])),$text);
}
//转换引号
while(preg_match('/([[^[]]*=s*)("|')([^2=[]]+)2([^[]]*])/i',$text,$mat)){
$text=str_replace($mat[0],$mat[1].'|'.$mat[3].'|'.$mat[4],$text);
}
//空属性转换
$text = str_replace('''','||',$text);
$text = str_replace('""','||',$text);
//过滤错误的单个引号
while(preg_match('/[[^[]]*("|')[^[]]*]/i',$text,$mat)){
$text=str_replace($mat[0],str_replace($mat[1],'',$mat[0]),$text);
}
//转换其它所有不合法的 < >
           $text = str_replace('<','<',$text);
$text = str_replace('>','>',$text);
           $text = str_replace('"','"',$text);
           //反转换
           $text = str_replace('[','<',$text);
$text = str_replace(']','>',$text);
           $text = str_replace('|','"',$text);
           //过滤多余空格
           $text = str_replace(' ',' ',$text);
           return $text;
       }
    ?>

PHP uses str_replace() function to prevent injection_PHP tutorial