Unzipping larger files with PHP

Question

I'm trying to unzip a 14MB archive with PHP with code like this:

    $zip = zip_open("c:\kosmas.zip");
    while ($zip_entry = zip_read($zip)) {
    $fp = fopen("c:/unzip/import.xml", "w");
    if (zip_entry_open($zip, $zip_entry, "r")) {
     $buf = zip_entry_read($zip_entry, zip_entry_filesize($zip_entry));
     fwrite($fp,"$buf");
     zip_entry_close($zip_entry);
     fclose($fp);
     break;
    }
   zip_close($zip);
  }

It fails on my localhost with 128MB memory limit with the classic " Allowed memory size of blablabla bytes exhausted ". On the server, I've got 16MB limit, is there a better way to do this so that I could fit into this limit? I don't see why this has to allocate more than 128MB of memory. Thanks in advance.

Solution: I started reading the files in 10Kb chunks, problem solved with peak memory usage arnoud 1.5MB.

        $filename = 'c:\kosmas.zip';
        $archive = zip_open($filename);
        while($entry = zip_read($archive)){
            $size = zip_entry_filesize($entry);
            $name = zip_entry_name($entry);
            $unzipped = fopen('c:/unzip/'.$name,'wb');
            while($size > 0){
                $chunkSize = ($size > 10240) ? 10240 : $size;
                $size -= $chunkSize;
                $chunk = zip_entry_read($entry, $chunkSize);
                if($chunk !== false) fwrite($unzipped, $chunk);
            }

            fclose($unzipped);
        }

Answer 1

Why do you read the whole file at once?

 $buf = zip_entry_read($zip_entry, zip_entry_filesize($zip_entry));
 fwrite($fp,"$buf");

Try to read small chunks of it and writing them to a file.

Answer 2

仅仅因为一个zip小于PHP的内存限制并且解压缩也是如此，一般不考虑PHP的开销，更重要的是实际解压缩文件所需的内存，这虽然我不是压缩专家我d期望可能远远超过最终的解压缩大小。

Answer 3

function my_unzip($full_pathname){

    $unzipped_content = '';
    $zd = gzopen($full_pathname, "r");

    while ($zip_file = gzread($zd, 10000000)){
        $unzipped_content.= $zip_file;
    }

    gzclose($zd);

    return $unzipped_content;

}

Answer 4

For a file of that size, perhaps it is better if you use shell_exec() instead:

shell_exec('unzip archive.zip -d /destination_path');

PHP must not be running in safe mode and you must have access to both shell_exec and unzip for this method to work.

Update :

Given that command line tools are not available, all I can think of is to create a script and send the file to a remote server where command line tools are available, extract the file and download the contents.