php - 在目录中搜索以查找具有特定文件扩展名的文件

Question

使用 php 搜索目录并找出目录是否有任何以指定文件扩展名结尾的文件（如 mp3 或 pdf）的最佳方法是什么？我想知道我是否可以用 if 语句来做到这一点。

Answer 1

使用glob()函数：

foreach (glob("*.{pdf,mp3}", GLOB_BRACE) as $filename) {
    echo "$filename\n";
}

◾GLOB_BRACE - Expands {a,b,c} to match 'a', 'b', or 'c'

Answer 2

另请查看 PHP 的 SPL DirectoryIterator。

Answer 3

冒着使简单任务过于复杂的风险，这里有一种 OO SPL 方法来处理这个问题。

<?php
/**
* Provides a means to pull all files matching the specific pattern within a given folder and at option enumerate all sub folders
* within the same path. 
*/
class FileSearchIterator extends FilterIterator
{
    protected $_path, $_extension, $_startWith, $_endWith;

    /**
     * Provides an iterator to a collection of filepath matching the given rules.
     *
     * If recursive is true also considers sub directories.
     *
     * Use in a foreach loop.
     *
     * @param string $path
     * @param boolean $recursive If set to true recursive sub directories are enumerated.
     * @param mixed $extension Either a single extension to accept or an array of such, null for no filter
     * @param mixed $startWith  Either a single string that must appear at the beginning of the file name, an array of such or null.
     * @param mixed $endWith Either a single string that must appear at the end of the file name, an array of such or null.
     * @throws LogicException
     * @return FileSearchIterator
     */
    public function __construct($path, $recursive = false, $extension = null, $startWith = null, $endWith = null)
    {
        if(! is_dir($path)) throw new LogicException("$path : is not a valid folder accessible to this process");

        if(! is_array($extension)) $extension = array($extension);
        if(! is_array($startWith)) $startWith = array($startWith);
        if(! is_array($endWith)) $endWith = array($endWith);

        $this->_path = $path;
        $this->_extension = $extension;
        $this->_startWith = $startWith;
        $this->_endWith = $endWith;

        $it = $recursive ? new RecursiveDirectoryIterator($path, FilesystemIterator::KEY_AS_PATHNAME | FilesystemIterator::CURRENT_AS_SELF) : new DirectoryIterator($path);

        if($recursive) parent::__construct(new RecursiveIteratorIterator($it));
        else parent::__construct($it);        
    }

    /**
    * Filter function implemented for the FilterIterator
    *
     * @return bool
     */
    public function accept()
    {        
        $info = $this->getInnerIterator()->current();

        if (!$info instanceof SplFileInfo) return false;
        if (!$info->isFile() || $info->isDot()) return false;

        $info = pathinfo($info->getFilename());

        if($this->_extension[0] != null)
        {//only allow specified extensions
            if(! isset($info['extension']) || $info['extension'] == null) return false;
            $ext = $info['extension'];
            if(! in_array($ext,$this->_extension)) return false;
        }

        if($this->_startWith[0] != null)
        {//string match from start of filename
            $found = false;
            $file = $info['filename'];

            foreach($this->_startWith as $filter)
            {
                if(strncmp($file, $filter, strlen($filter)) == 0) 
                {
                    $found = true;
                    break;
                }  
            }

            if(! $found) return false;
        }

        if($this->_endWith[0] != null)
        {//string match from end of filename
            $found = false;
            $file = $info['filename'];

            foreach($this->_endWith as $filter)
            {
                if(substr_compare($file, $filter, -strlen($filter), strlen($filter)) === 0)
                {
                    $found = true;
                    break;
                }  
            }

            if(! $found) return false;
        }

        return true;
    }
}

用法 ：

$fileScanner = new FileSearchIterator(path, true, array('mp3', 'pdf'));
            foreach($fileScanner as $file)
            {
                $file-> //do something
            }