How can I remove duplicates and add a new unique file? - php

Question

I have on my website to grab 5 random files from all the files in my directory and all is going well but about %50 of the time I get a duplicate. I would like to:
1) Remove duplicate
2) Replace with new unique file
.. or maybe I can prevent duplicates in an easier manner all together? I tried to find a function for this without asking a question of here but I have not found one. Any ideas? Thanks!!
<?php
//define stuff
$dir = "uploads/";
$allfiles = array_diff(scandir($dir), array('.', '..'));
echo '<pre>';
print_r("all files ready for access");
echo '<pre>';
// create zip
$zip = new ZipArchive();
$zip_name = "zipfile.zip";
if($zip->open($zip_name, ZIPARCHIVE::CREATE)!==TRUE){
$error .= "* Sorry ZIP creation failed at this time";
}
else {
echo '<pre>';
print("created zip");
echo '<pre>';
}
// array of random files
$n=1;
while ($n<=6){
$n ++;
$file = array_rand($allfiles);
$randomfile = $allfiles[$file];
echo '<pre>';
print_r($randomfile);
echo '<pre>';
if (file_exists($dir.$randomfile)) {
$content = $dir.$randomfile;
echo '<pre>';
print_r($content);
echo '<pre>';
$zip->addfile($content,$randomfile);
echo 'ok';
} else {
echo 'failed';
}
}
//present for download
$zip->close();
ob_get_clean();
header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: private", false);
header("Content-Type: application/zip");
header("Content-Disposition: attachment; filename=" . basename($zip_name) . ";" );
header("Content-Transfer-Encoding: binary");
header("Content-Length: " . filesize($zip_name));
readfile($zip_name);
if(file_exists($zip_name))
{
unlink('zipfile.zip');
}
?>

Answer 1

Just check if you already found this file. And if you already found it, get a new one by continuing without incrementing $n.
Look at this:
// array of random files
$n = 1;
$myfiles = [];
while ($n<=6){
$file = array_rand($allfiles);
$randomfile = $allfiles[$file];
if(!in_array($randomfile, $myfiles)) { // this line checks if you already got this file
$myfiles[] = $randomfile;
} else {
continue; // if you already got it, continue (http://php.net/manual/de/control-structures.continue.php)
}
echo '<pre>';
print_r($randomfile);
echo '<pre>';
if (file_exists($dir.$randomfile)) {
$content = $dir.$randomfile;
echo '<pre>';
print_r($content);
echo '<pre>';
$zip->addfile($content,$randomfile);
echo 'ok';
} else {
echo 'failed';
}
$n++; // increment in the end
}

Answer 2

You can pass a second parameter to the array_randfunction:
$my_files = array_rand($allfiles, 5);
or shuffle the array and get -for example- the first five items:
shuffle($allfiles);
// now $allfiles[0...4] are 5 different files.

Answer 3

create a an array for the files already added to the zip :
$added = //array
$zip->addfile($content,$randomfile);
array_push($added,$randomfile)
and check any new file in the above array before inserting:
if(!in_array($randomfile, $added)){
//add the file to zip
}