How to get ZipArchive to not overwrite certain files and folders - php

Question

I would like to extract a zip folder to a location and to replace all files and folders except a few, how can I do this?
I currently do the following.
$backup = realpath('./backup/backup.zip');
$zip = new ZipArchive();
if ($zip->open("$backup", ZIPARCHIVE::OVERWRITE) !== TRUE) {
die ('Could not open archive');
}
$zip->extractTo('minus/');
$zip->close();
How can I put conditions in for what files and folders should NOT be replaced? It would be great if some sort of loop could be used.
Thanks all for any help

Answer 1

You could do something like this, I tested it and it works for me:
// make a list of all the files in the archive
$entries = array();
for ($idx = 0; $idx < $zip->numFiles; $idx++) {
$entries[] = $zip->getNameIndex($idx);
}
// remove $entries for the files you don't want to overwrite
// only extract the remaining $entries
$zip->extractTo('minus/', $entries);
This solution is based on the numFiles property and the getNameIndex method, and it works even when the archive is structured into subfolders (the entries will look like /folder/subfolder/file.ext).
Also, the extractTo method takes a second optional paramer that holds the list of files to be extracted.

Answer 2

If you just want to extract specific files from the archive (and you know what they are) then use the second parameter (entries).
$zip->extractTo('minus/', array('file1.ext', 'newfile2.xml'));
If you want to extract all the files that do not exist, then you can try one of the following:
$files = array();
for($i = 0; $i < $zip->numFiles; $i++) {
$filename = $zip->getNameIndex($i);
// if $filename not in destination / or whatever the logic is then
$files[] = $filename;
}
$zip->extractTo($path, $files);
$zip->close();
You can also use $zip->getStream( $filename ) to read a stream that you then write to the destination file.