sql安全过滤函数

/**
 * 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);
    $string = str_replace('<','&lt;',$string);
    $string = str_replace('>','&gt;',$string);
    $string = str_replace("{",'',$string);
    $string = str_replace('}','',$string);
    $string = str_replace('\\','',$string);
    return $string;
}

/**
 * xss过滤函数
 *
 * @param $string
 * @return string
 */
function remove_xss($string) { 
    $string = preg_replace('/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+/S', '', $string);

    $parm1 = Array('javascript', 'vbscript', 'expression', 'applet', 'meta', 'xml', 'blink', 'link', 'script', 'embed', 'object', 'iframe', 'frame', 'frameset', 'ilayer', 'layer', 'bgsound', 'title', 'base');

    $parm2 = Array('onabort', 'onactivate', 'onafterprint', 'onafterupdate', 'onbeforeactivate', 'onbeforecopy', 'onbeforecut', 'onbeforedeactivate', 'onbeforeeditfocus', 'onbeforepaste', 'onbeforeprint', 'onbeforeunload', 'onbeforeupdate', 'onblur', 'onbounce', 'oncellchange', 'onchange', 'onclick', 'oncontextmenu', 'oncontrolselect', 'oncopy', 'oncut', 'ondataavailable', 'ondatasetchanged', 'ondatasetcomplete', 'ondblclick', 'ondeactivate', 'ondrag', 'ondragend', 'ondragenter', 'ondragleave', 'ondragover', 'ondragstart', 'ondrop', 'onerror', 'onerrorupdate', 'onfilterchange', 'onfinish', 'onfocus', 'onfocusin', 'onfocusout', 'onhelp', 'onkeydown', 'onkeypress', 'onkeyup', 'onlayoutcomplete', 'onload', 'onlosecapture', 'onmousedown', 'onmouseenter', 'onmouseleave', 'onmousemove', 'onmouseout', 'onmouseover', 'onmouseup', 'onmousewheel', 'onmove', 'onmoveend', 'onmovestart', 'onpaste', 'onpropertychange', 'onreadystatechange', 'onreset', 'onresize', 'onresizeend', 'onresizestart', 'onrowenter', 'onrowexit', 'onrowsdelete', 'onrowsinserted', 'onscroll', 'onselect', 'onselectionchange', 'onselectstart', 'onstart', 'onstop', 'onsubmit', 'onunload');

    $parm = array_merge($parm1, $parm2); 

    for ($i = 0; $i < sizeof($parm); $i++) { 
        $pattern = '/'; 
        for ($j = 0; $j < strlen($parm[$i]); $j++) { 
            if ($j > 0) { 
                $pattern .= '('; 
                $pattern .= '(&#[x|X]0([9][a][b]);?)?'; 
                $pattern .= '|(&#0([9][10][13]);?)?'; 
                $pattern .= ')?'; 
            }
            $pattern .= $parm[$i][$j]; 
        }
        $pattern .= '/i';
        $string = preg_replace($pattern, ' ', $string); 
    }
    return $string;
}

/**
 * 过滤ASCII码从0-28的控制字符
 * @return String
 */
function trim_unsafe_control_chars($str) {
    $rule = '/[' . chr ( 1 ) . '-' . chr ( 8 ) . chr ( 11 ) . '-' . chr ( 12 ) . chr ( 14 ) . '-' . chr ( 31 ) . ']*/';
    return str_replace ( chr ( 0 ), '', preg_replace ( $rule, '', $str ) );
}