Code summary for checking whether a file or directory exists in php_PHP tutorial

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

if (file_exists("C:blablaphp"))
{echo "yes";}
else
{echo "no";}

/**
* File or directory permission check function
*
* @access public
* @param string $file_path File path
* @param bool $rename_prv Whether to check the execution of rename when checking modification permissions () Function permissions
*
* @return int The value range of the return value is {0 <= x <= 15}, and the meaning of each value can be derived from a combination of four binary numbers.
* The return value is in binary notation. The four digits from high to low respectively represent
* executable rename() function permissions, permissions to append content to files, permissions to write files, and permissions to read files. .
*/
function file_mode_info($file_path)
{
/* If it does not exist, it will not be readable or writable , cannot be changed*/
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 if the directory is readable*/
$dir = @opendir($file_path);
if ($dir === false)
{
return $mark; //If the directory fails to open, return directly to the directory that cannot be modified, written, or read
}
if (@readdir($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 $mark; //If the file creation in the directory fails , returns unwritable.
}
if (@fwrite($fp, 'directory access testing.') !== false)
{
$mark ^= 2; //The directory is writable and readable 011, directory Writable but not readable 010
}
@fclose($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 rename() function has been executed in the directory Permissions*/
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;
}

/*****************************************************
* Write xml data stream to xml file
* @param $xmlData
* @return bool|string
*/
function writeXmlFile($xmlData)
{
$time = time(); //Get the timestamp for naming the file
$path = dirname(__FILE__); //Get the current absolute path
$path = substr_replace($path, "", stripos($path, "actionsdata")); //Replace the inherent path where this file is located Empty
$path .= "xmlFiles"; //Storage directory name
/*Determine whether the target directory exists, if not, create a new one*/
if(!is_dir($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 file stream*/
$flag = fwrite($fp, $xmlData);
if(!$flag)
{
return false;
}
fclose($fp);
return $filePathAndName;
}