php常用自定义函数

<?php 
/**
 * 删除指定路径下文件
 * @param  [type] $path 文件路径
 */
function delFile($path) {
    try {
        if(file_exists($path)) {
            unlink($path);
        }
    } catch (Exception $e) {
        echo $e->getMessage();
    }
}
/**
 * 正则去掉字符串中的html标签
 * @param unknown $str
 * @return string
 */
function filterHtml($str) {
    $str = str_replace("&nbsp;","",strip_tags($str));
    $str = preg_replace('/((\s)*(\n)+(\s)*)/i','', $str);
    $str = trim($str);
    return $str;
}
/**
 * 将文件大小换算成合适的单位
 * @param int $size
 * @return $size
 */
function convertSize($size) {
    // Adapted from: http://www.php.net/manual/en/function.filesize.php  
    $mod = 1024;
    $units = explode(' ', 'B KB MB GB TB PB');
    for($i = 0; $size > $mod; $i ++) {
        $size /= $mod;
    }
    return round($size, 2).' '.$units[$i];
}
/**
 * 列出目录下的文件名
 * @param  [type] $DirPath 目录
 */
function listDirFiles($DirPath){
    if($dir = opendir($DirPath)){
        while(($file = readdir($dir))!== false){
            if(!is_dir($DirPath.$file)) { 
                echo "filename: $file<br />";
            } 
        } 
    }
}
/**
 * php强制下载文件
 * @param String $filename 文件名称
 */
function download($filename){ 
    if ((isset($filename))&&(file_exists($filename))){ 
       header("Content-length: ".filesize($filename)); 
       header('Content-Type: application/octet-stream'); 
       header('Content-Disposition: attachment; filename="' . $filename . '"'); 
       readfile("$filename"); 
    } else { 
       echo "Looks like file does not exist!"; 
    } 
}

/**
 * 防止网页复制代码
 */
echo "<script>
document.oncontextmenu=new Function("event.returnValue=false;");
document.onselectstart=new Function("event.returnValue=false;");
</script>
";