PHP code to determine whether there is read and write permission for an empty directory of files-PHP Tutorial-php.cn

PHP code to determine whether there is read and write permission for an empty directory of files

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Release： 2023-02-28 20:50:02

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The php code that determines whether the empty directory of the file has read and write permissions

is_writable is used for processing. Remember that PHP may only be able to access the file with the user name running the webserver (usually 'nobody'). Does not count towards Safe Mode limits.
Example #1 is_writable() Example

<?php 
$filename = &#39;test.txt&#39;; 
if (is_writable($filename)) { 
echo &#39;The file is writable&#39;; 
} else { 
echo &#39;The file is not writable&#39;; 
} 
?>

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One problem with the above function is that filename is required. It is stipulated that the file to be checked must be a file, and the directory cannot be judged. Next, we will judge the empty directory.
Example 1
This function is very commonly used, especially in some projects that need to generate static files. Whether a directory can be used depends on whether the directory has permission to create files and delete files.

/* 
问题出现：如何检查一个目录是否可写，如何目录下还有目录和文件，那么都要检查 
思路： 
（1）首先先写出检查空目录是否可写的算法： 
在该目录中生成一个文件，如果不能生成，表明该目录没有写的权限 
（2）使用递归的办法来进行检查 
代码实现： 
*/ 
set_time_limit(1000); 
function check_dir_iswritable($dir_path){ 
$dir_path=str_replace(&#39;\&#39;,&#39;/&#39;,$dir_path); 
$is_writale=1; 
if(!is_dir($dir_path)){ 
$is_writale=0; 
return $is_writale; 
}else{ 
$file_hd=@fopen($dir_path.&#39;/test.txt&#39;,&#39;w&#39;); 
if(!$file_hd){ 
@fclose($file_hd); 
@unlink($dir_path.&#39;/test.txt&#39;); 
$is_writale=0; 
return $is_writale; 
} 
$dir_hd=opendir($dir_path); 
while(false!==($file=readdir($dir_hd))){ 
if ($file != "." && $file != "..") { 
if(is_file($dir_path.&#39;/&#39;.$file)){ 
//文件不可写，直接返回 
if(!is_writable($dir_path.&#39;/&#39;.$file)){ 
return 0; 
} 
}else{ 
$file_hd2=@fopen($dir_path.&#39;/&#39;.$file.&#39;/test.txt&#39;,&#39;w&#39;); 
if(!$file_hd2){ 
@fclose($file_hd2); 
@unlink($dir_path.&#39;/&#39;.$file.&#39;/test.txt&#39;); 
$is_writale=0; 
return $is_writale; 
} 
//递归 
$is_writale=check_dir_iswritable($dir_path.&#39;/&#39;.$file); 
} 
} 
} 
} 
return $is_writale; 
}

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The above example mainly uses fopen to create files in the directory. file or write content in the file, so that the read and write permissions of the directory can be determined.

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