So I'm going through reading and writing to files in PHP via PHP Docs and there's an example I didn't quite understand:
http://php.net/manual/en/function.readdir.php
if toward the end it shows an example like this:
<?php
if ($handle = opendir('.')) {
while (false !== ($entry = readdir($handle))) {
if ($entry != "." && $entry != "..") {
echo "$entry\n";
}
}
closedir($handle);
}
?>
In what case would . or .. ever be read?
The readdir API call iterates over all of the directories. So assuming you loop over the current directory (denoted by ".") then you get into an endless loop. Also, iterating over the parent directory (denoted by "..") is avoided to restrict the list to the current directory and beneath.
Hope that helps.
readdir('.') it's going to read everything - even itself? So I wouldn't run into either case if I declared a directory such as readdir('test_directory')
If you want to read directories using PHP, I would recommend you use the scandir function. Below is a demonstration of scandir
$path = __DIR__.'/images';
$contents = scandir($path);
foreach($contents as $current){
if($current === '.' || $current === '..') continue ;
if(is_dir("$path/$current")){
echo 'I am a directory';
} elseif($path[0] == '.'){
echo "I am a file with a name starting with dot";
} else {
echo 'I am a file';
}
}
Because in a UNIX filesystem, . and .. are like signposts, as far as I know. Certainly to this PHP function, anyway.
Keep them in there, you'll get some weird results (like endless loops, etc.) otherwise!
In *nix . is the present working directory and .. is the directory parent. However any file or directory preceded by a '.' is considered hidden so I prefer something like the following:
...
if ($entry[0] !== '.') {
echo "$entry\n";
}
...
This ensures that you don't parse "up" the directory tree, that you don't endlessly loop the present directory, and that any hidden files/folders are ignored.
