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

The following is an example code that checks whether a file exists:
Copy the code code as follows:
<?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 execution of the PHP file displays the following results:
The file C:blablaphphello.txt exists.
If the file does not exist, the result of executing the PHP file is:
The file C:\blabla\phphello.txt does not exist.
You can also use the File_exists function to test whether a directory exists, as shown in the sample code:
Copy the code code as follows:
if (file_exists ("C:\blabla\php"))
{echo "yes";}
Else
{echo "No";}

Instance
Copy the code code as follows:
/**
* File or directory permission check function
*
* @access Public
* @param string $file _path file path
* @param bool $rename _PRV Check permission to execute rename () function when checking for modify permissions
*
* @return int return value range is {0 <= x <= 15}, the meaning of each value can be introduced by a combination of four-bit binary numbers.
* return value in binary notation, four bits are represented by high to low respectively
* Executable Rename () function permission, can append content permission to file, writable file permission, read file permission.
*/
function File_mode_info ($file _path)
{
/* If not present, unreadable, non-writable, non-modified */
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 $mark; If the directory fails to open, directly returns the directory is non-modifiable, non-writable, unreadable
}
if (@readdir ($dir)!== false)
{
$mark ^= 1; Directory readable 001, directory unreadable 000
}
@closedir ($dir);
/* Check if the directory is writable */
$fp = @fopen ($test _file, ' WB ');
if ($fp = = = False)
{
return $mark; If the file creation in the directory fails, the return is not writable.
}
if (@fwrite ($fp, ' Directory Access testing. ')!== false)
{
$mark ^= 2; Directory writable readable 011, directory writable unreadable 010
}
@fclose ($FP);
@unlink ($test _file);
/* Check if 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 the directory for 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 as Read */
$fp = @fopen ($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)
{
$mark ^= 6; Can be modified writable readable 111, non-modifiable writable readable 011 ...
}
@fclose ($FP);
/* Check the directory for 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 if a directory exists
Copy the code code as follows:
/****************************************************
* XML data stream, written to XML file
* @param $xmlData
* @return bool|string
*/
function Writexmlfile ($xmlData)
{
$time = time (); Gets the timestamp used to name the file
$path = DirName (__file__); Gets the current absolute path
$path = Substr_replace ($path, "", Stripos ($path, "Actions\data")); Replace the inherent path of this file with an empty
$path. = "Xmlfiles\"; Store Directory Name
/* Determine if the target directory exists, does not exist, and then new */
if (!is_dir ($path))
{
mkdir ($path); New Catalog
}
/* Record full path and file name */
$filePathAndName = $path. $time. ". XML ";
/* Open file with file name < timestamp > + <.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;
}

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