Code summary for checking whether a file or directory exists in php

The following is a simple example code to check whether the file exists:
Copy the code The code is as follows:
$filename = '/path/to/foo.txt';
if (file_exists($filename)) {
echo "The file $filename exists";
} else {
echo "The file $filename does not exist";
}
?>

If the file exists, the displayed result of executing the PHP file is:
The file C:blablaphphello.txt exists.
If the file does not exist, the displayed result of executing the PHP file is:
The file C:blablaphphello.txt does not exist.
You can also use the file_exists function to test whether a directory exists, sample code As follows:
Copy code The code is as follows:
if (file_exists("C:blablaphp"))
{echo "yes";}
else
{echo "no";}

Example
Copy code The code is as follows:
/* *
* File or directory permission check function
*
* @access public
* @param string $file_path File path
* @param bool $rename_prv Whether to check the permission to execute the rename() function when checking modification permissions
*
* @ return int The value range of the return value is {0 * The return value is in binary notation, and the four digits from high to low respectively represent
* permissions to execute the rename() function, permissions to append content to files, permissions to write files, and permissions to read files.
*/
function file_mode_info($file_path)
{
/* If it does not exist, it is unreadable, unwritable, and unchangeable*/
if (!file_exists($file_path))
{
return false;
}
$mark = 0;
if (strtoupper(substr(PHP_OS, 0, 3)) == 'WIN')
{
/* Test file*/
$test_file = $file_path . '/cf_test.txt';
/* If it is a directory*/
if (is_dir($file_path))
{
/* Check whether the directory is readable*/
$dir = @opendir($file_path);
if ($dir === false)
{
return $mark; //If the directory opening fails, return directly to the directory which cannot be modified, written or read
}
if (@readdir($dir) !== false)
{
$mark ^= 1; //The directory is readable 001, the directory is unreadable 000
}
@closedir($dir);
/* Check whether the directory is writable*/
$fp = @fopen($test_file, 'wb');
if ($ fp === false)
{
return $mark; //If the file in the directory fails to be created, it returns unwritable.
}
if (@fwrite($fp, 'directory access testing.') !== false)
{
$mark ^= 2; //The directory is writable and readable 011, the directory is writable and unreadable 010
}
@fclose($fp);
@unlink($test_file);
/* Check whether the directory can be modified*/
$fp = @fopen($test_file, 'ab+');
if ($fp === false)
{
return $mark;
}
if (@fwrite($fp, "modify test.rn") !== false)
{
$mark ^= 4;
}
@fclose($fp);
/* Check whether the directory has permission to execute the rename() function*/
if (@rename($test_file, $test_file) !== false)
{
$mark ^= 8;
}
@unlink($test_file );
}
/* If it is a file*/
elseif (is_file($file_path))
{
/* Open in read mode*/
$fp = @fopen($file_path, 'rb');
if ( $fp)
{
$mark ^= 1; //Readable 001
}
@fclose($fp);
/* Try to modify the file*/
$fp = @fopen($file_path, 'ab+') ;
if ($fp && @fwrite($fp, '') !== false)
{
$mark ^= 6; //Can be modified, written and read 111, cannot be modified, written and read 011...
}
@fclose($fp);
/* Check whether the directory has permission to execute the rename() 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 whether the directory exists
Copy code The code is as follows:
/*****************************************************
* Write xml data stream to xml file
* @param $xmlData
* @return bool|string
*/
function writeXmlFile($xmlData)
{
$time = time (); //Get the timestamp, used to name the file
$path = dirname(__FILE__); //Get the current absolute path
$path = substr_replace($path, "", stripos($path, "actionsdata")); //Replace the inherent path of this file with an empty one
$path .= "xmlFiles"; //Storage directory name
/ *Determine whether the target directory exists, create a new one if it does not exist*/
if(!is_dir($path))
{
mkdir($path); //Create a new directory
}
/*Record the complete path and file name*/
$filePathAndName = $path.$time.".xml";
/*Open the file, the file name is + <.xml>*/
$fp = fopen($filePathAndName, "w") ;
if(!$fp)
{
return false;
}
/*Write to file stream*/
$flag = fwrite($fp, $xmlData);
if(!$flag)
{
return false ;
}
fclose($fp);
return $filePathAndName;
}