为foreach提供的无效参数（）

Question

下面的代码每60秒删除文件夹“Images”内的文件，它可以工作，但是当文件夹为空时，它会显示：Warning：为foreach提供的无效参数（） 这是固定的一样，如果没有文件，说“文件夹为空，而不是该警告..

<?php 
$expiretime=1; 

$tmpFolder="Images/"; 
$fileTypes="*.*"; 

foreach (glob($tmpFolder . $fileTypes) as $Filename) { 

// Read file creation time 
$FileCreationTime = filectime($Filename); 

// Calculate file age in seconds 
$FileAge = time() - $FileCreationTime; 

// Is the file older than the given time span? 
if ($FileAge > ($expiretime * 60)){ 

// Now do something with the olders files... 

echo "The file $Filename is older than $expiretime minutes\r\n"; 

//delete files: 
unlink($Filename); 
} 

} 
?> 

Answer 1

由于水珠（）可能无法可靠地返回一个空数组空匹配（See "note" in Return section of the docs)，你只需要一个if声明保护您的循环，如下所示：

$files = glob($tmpFolder . $fileTypes); 
if (is_array($files) && count($files) > 0) { 
    foreach($files as $Filename) { 
     // Read file creation time 
     $FileCreationTime = filectime($Filename); 

     // Calculate file age in seconds 
     $FileAge = time() - $FileCreationTime; 

     // Is the file older than the given time span? 
     if ($FileAge > ($expiretime * 60)){ 

     // Now do something with the olders files... 

     echo "The file $Filename is older than $expiretime minutes\r\n"; 

     //delete files: 
     unlink($Filename); 
    } 
} else { 
    echo 'Your error here...'; 
}