PharData offsetExists on filename prefixed with ".\" - php

Question

I have a .tar.gz file downloaded from an external API which we have to implement. It contains images for an object.
I'm not sure how they managed to compress it this way, but the files are basically prefixed with the "current directory". It looks like this in WinRAR:
And like this in 7-Zip, note the .tar first level, and "." second level:
-> ->
When calling
$file = 'archive.tar.gz';
$phar = new PharData($file, FilesystemIterator::CURRENT_AS_FILEINFO);
var_dump($phar->offsetGet('./12613_s_cfe3e73.jpg'));
I get the exception:
Cannot access phar file entry '/12613_s_cfe3e73.jpg' in archive '{...}/archive.tar.gz'
Calling a file which does not exist, e.g.:
var_dump($phar->offsetGet('non-existent.jpg'));
Or calling it without the directory seperator, e.g.:
var_dump($phar->offsetGet('12613_s_cfe3e73.jpg'));
I get a
Entry 12613_s_cfe3e73.jpg does not exist
Exception.
It is not possible to get the archive formatted differently. Does anyone have an idea how to solve this?

Answer 1

Ended up using Archive_Tar. There must be something wrong in the source code of PHP, though I don't think this is the "normal" way of packaging a .tar either.
Unfortunately I'm not very good at C, but it's probably in here (line 1214) or here.
This library seems to handle it just fine, using this example code:
$file = 'archive.tar.gz';
$zip = new Archive_Tar($file);
foreach ($zip->listContent() as $file) {
echo $file['filename'] . '<br>';
}
Result:
./12613_s_f3b483d.jpg
./12613_s_cfe3e73.jpg
./1265717_s_db141dc.jpg
./1265717_s_af5de56.jpg
./1265717_s_b783547.jpg
./1265717_s_35b11f9.jpg
./1265716_s_83ef572.jpg
./1265716_s_9ac2725.jpg
./1265716_s_c5af3e9.jpg
./1265716_s_c070da3.jpg
./1265715_s_4339e8a.jpg
Note the filenames are still prefixed with "./" just like they are in WinRAR.

Answer 2

If you want to stick to using PharData, i suggest a more conservative, two-step approach, where you first decompress the gz and then unarchive all files of the tar to a target folder.
// decompress gz archive to get "/path/to/my.tar" file
$gz = new PharData('/path/to/my.tar.gz');
$gz->decompress();
// unarchive all files from the tar to the target path
$tar = new PharData('/path/to/my.tar');
$tar->extractTo('/target/path');
But it looks like you want to select individual files from the tar.gz archive directly, right?
It should work using fopen() with a StreamReader (compress.zlib or phar) and selecting the individual file. Some examples:
$f = fopen("compress.zlib://http://some.website.org/my.gz/file/in/the/archive", "r");
$f = fopen('phar:///path/to/my.tar.gz//file/in/archive', 'r');
$filecontent = file_get_contents('phar:///some/my.tar.gz/some/file/in/the/archive');
Streaming should also work, when using Iterators:
$rdi = new RecursiveDirectoryIterator('phar:///path/to/my.tar.gz')
$rii = new RecursiveIteratorIterator($rdi, RecursiveIteratorIterator::CHILD_FIRST);
foreach ($rii as $splFileInfo){
echo file_get_contents($splFileInfo->getPathname());
}
The downside is that you have to buffer the stream and save it to file.
Its not a direct file extraction to a target folder.