php recursive folder readdir vs find performance

Question

i came across few articles about performance and readdir here is the php script:

function getDirectory( $path = '.', $level = 0 ) { 
    $ignore = array( 'cgi-bin', '.', '..' );
    $dh = @opendir( $path );
    while( false !== ( $file = readdir( $dh ) ) ){
        if( !in_array( $file, $ignore ) ){
            $spaces = str_repeat( ' ', ( $level * 4 ) );
            if( is_dir( "$path/$file" ) ){
                echo "$spaces $file\n";
                getDirectory( "$path/$file", ($level+1) );
            } else {
                echo "$spaces $file\n";
            }
        }
    }
    closedir( $dh );
}
getDirectory( "." );

this echo the files/ folders correctly.

now i found this:

$t = system('find');
print_r($t);

which also find all the folders and files then i can create an array like the first code.

i think the system('find'); is faster than the readdir but i want to know if it'S a good practice? thank you very much

A system call certainly isn't portable. Your example code is dependent upon a *nix OS. — nickb, Nov 30 '11 at 01:39
It's also a bad idea to get used to using `system()` calls. They should be fine without parameters, but if you construct them dynamically based on user input, you're likely to create bad security holes. — millimoose, Nov 30 '11 at 02:15

score 36 · Accepted Answer · answered Nov 30 '11 at 13:55

Here's my benchmark using a simple for loop with 10 iteration on my server:

$path = '/home/clad/benchmark/';
// this folder has 10 main directories and each folder as 220 files in each from 1kn to 1mb

// glob no_sort = 0.004 seconds but NO recursion
$files = glob($path . '/*', GLOB_NOSORT);

// 1.8 seconds - not recommended
exec('find ' . $path, $t);
unset($t);

// 0.003 seconds
if ($handle = opendir('.')) {
 while (false !== ($file = readdir($handle))) {
  if ($file != "." && $file != "..") {
   // action
  }
 }
 closedir($handle);
}

// 1.1 seconds to execute
$path = realpath($path);
$objects = new RecursiveIteratorIterator(
 new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::SELF_FIRST);
  foreach($objects as $name => $object) {
   // action
  }
}

Clearly the readdir is faster to use specially if you have lots of traffic on your site.

Good answer, but am I missing something... the `readdir()` solution on its own is not recursive. Will this not skew the results? — Ben Everard, Feb 08 '12 at 14:34

score 2 · Answer 2 · answered Nov 30 '11 at 01:40

2

'find' is not portable, it's a unix/linux command. readdir() is portable and will work on Windows or any other OS. Moreover, 'find' without any parameters is recursive, so if you're in a dir with lots of subdirs and files, you will get to see all of them, rather than only the contents of that $path.

answered Nov 30 '11 at 01:40

favoretti

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Although I see that your function is recursive as well, so ignore the rant about recursiveness. Note though, that output of 'find' is also formatted in a peculiar way. – favoretti Nov 30 '11 at 01:43
i never used windows so it's unix or linux only, for the formating i can deal with – rcs20 Nov 30 '11 at 01:45
2

Well, let's put it this way. Speed-wise it won't matter much, but to control behavior of function using find - you'll need to tweak 'find' commandline parameters, rather than using code-way of controlling your function behavior. I, for one, wouldn't go with find, unless there would be a very specific reason to do it. – favoretti Nov 30 '11 at 01:50
you saying if i look for files only i can use: `-type f` instead of in the php `is_file` or is_dir? – rcs20 Nov 30 '11 at 01:56
Yep, you can do that if you want to look for files only. – favoretti Nov 30 '11 at 01:59

php recursive folder readdir vs find performance

2 Answers2