A code summary in php that checks for the existence of a file or directory

Here is a simple example code to check if a file exists:

 
<?php 
$filename = '/path/to/foo.txt'; 
if (file_exists($filename)) { 
echo "The file $filename exists"; 
} else { 
echo "The file $filename does not exist"; 
} 
?> 

If the file exists, the display result of executing the PHP file is:
The file C:blablaphphello.txt exists.
If the file does not exist, the PHP file is displayed as:
The file C:\blabla\phphello.txt does not exist.
You can also test the existence of a directory with the file_exists function. The code is as follows:

 
if (file_exists("C:\blabla\php")) 
{echo "yes";} 
else 
{echo "no";} 

The instance

 
/** 
*  File or directory permission checking function  
* 
* @access public 
* @param string $file_path  The file path  
* @param bool $rename_prv  Whether to check execution when checking for modification permissions rename() Permission of a function  
* 
* @return int  The return value ranges from {0 <= x <= 15} , the meaning of each value can be determined by 4 position 2 Base number combination.  
*  The return value in 2 In base counting, 4 The bits are represented from high to low  
*  The executable rename() Function permission, can append content permission to the file, can write to the file permission, can read the file permission.  
*/ 
function file_mode_info($file_path) 
{ 
/*  If it does not exist, it cannot be read, written or changed  */ 
if (!file_exists($file_path)) 
{ 
return false; 
} 
$mark = 0; 
if (strtoupper(substr(PHP_OS, 0, 3)) == 'WIN') 
{ 
/*  The test file  */ 
$test_file = $file_path . '/cf_test.txt'; 
/*  If it's a directory  */ 
if (is_dir($file_path)) 
{ 
/*  Check that the directory is readable  */ 
$dir = @opendir($file_path); 
if ($dir === false) 
{ 
return $mark; // If the directory fails to open, the directory is returned unmodified, unwritten, and unreadable  
} 
if (@readdir($dir) !== false) 
{ 
$mark ^= 1; // Directory readable  001 , the directory is not readable  000 
} 
@closedir($dir); 
/*  Check that the directory is writable  */ 
$fp = @fopen($test_file, 'wb'); 
if ($fp === false) 
{ 
return $mark; // If file creation in the directory fails, return unwritable.  
} 
if (@fwrite($fp, 'directory access testing.') !== false) 
{ 
$mark ^= 2; // The contents are writable and readable 011 , the directory is writable and unreadable  010 
} 
@fclose($fp); 
@unlink($test_file); 
/*  Check that the directory is modifiable  */ 
$fp = @fopen($test_file, 'ab+'); 
if ($fp === false) 
{ 
return $mark; 
} 
if (@fwrite($fp, "modify test.rn") !== false) 
{ 
$mark ^= 4; 
} 
@fclose($fp); 
/*  Check the directory for execution rename() Permission of a function  */ 
if (@rename($test_file, $test_file) !== false) 
{ 
$mark ^= 8; 
} 
@unlink($test_file); 
} 
/*  If it's a file  */ 
elseif (is_file($file_path)) 
{ 
/*  Open as a read  */ 
$fp = @fopen($file_path, 'rb'); 
if ($fp) 
{ 
$mark ^= 1; // Can be read  001 
} 
@fclose($fp); 
/*  Try to modify the file  */ 
$fp = @fopen($file_path, 'ab+'); 
if ($fp && @fwrite($fp, '') !== false) 
{ 
$mark ^= 6; // Modifiable, writable, and readable  111 , unmodifiable, writable and readable 011... 
} 
@fclose($fp); 
/*  Check the directory for execution rename() Permission of a function  */ 
if (@rename($test_file, $test_file) !== false) 
{ 
$mark ^= 8; 
} 
} 
} 
else 
{ 
if (@is_readable($file_path)) 
{ 
$mark ^= 1; 
} 
if (@is_writable($file_path)) 
{ 
$mark ^= 14; 
} 
} 
return $mark; 
} 

PHP determines if the directory exists

 
/**************************************************** 
*  will xml Data flow, write to xml file  
* @param $xmlData 
* @return bool|string 
*/ 
function writeXmlFile($xmlData) 
{ 
$time = time(); // Gets a timestamp to name the file  
$path = dirname(__FILE__); // Gets the current absolute path  
$path = substr_replace($path, "", stripos($path, "actions\data")); // Replace the proper path where this file resides with empty  
$path .= "xmlFiles\"; // Store directory name  
/* Determine whether the target directory exists, does not exist, new */ 
if(!is_dir($path)) 
{ 
mkdir($path); // The new directory  
} 
/* Record the full path and file name */ 
$filePathAndName = $path.$time.".xml"; 
/* Open the file, file name < The time stamp > + <.xml>*/ 
$fp = fopen($filePathAndName, "w"); 
if(!$fp) 
{ 
return false; 
} 
/* Write file stream */ 
$flag = fwrite($fp, $xmlData); 
if(!$flag) 
{ 
return false; 
} 
fclose($fp); 
return $filePathAndName; 
}