PHP ZipArchive getFromName can't read file with relative path

Question

I'm trying to read a file content from a zip file with ZipArchive with the method getFromName. My file name has a double dot in it ( .. ). Here's my code:

$zip = new ZipArchive();

$zip->open('book.zip');

$content = $zip->getFromName('book/html/../README.md');

var_dump($content);

The structure of my zip file is this:

Archive:  book.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
        0  2016-06-01 11:09   book/
        0  2016-06-01 11:02   book/html/
     1855  2016-06-01 11:02   book/html/composer.json
     2354  2016-06-01 11:09   book/README.md
---------                     -------
     4209                     4 files

My PHP script is in the same directory as my zip file. When I try to list the file in the folder that I have zipped with Linux command like this:

ls -l book/html/../README.md 

It works perfectly. I don't understand why ZipArchive can't read this relative path correctly.

Note : I know that I can read the file with the absolute path: book/README.md but I really need to use the relative path with .. because the file paths are loaded dynamically from another place and I don't have a control on them.

Answer 1

I spent a day or so on a similar issue trying to read relative file paths including ".." change directories. ZipArchive is unable to handle those paths if the file is not extracted. The best solution I came up with without having to extract the Zip, was to use the following function to get the full path for the file you want: http://php.net/manual/en/function.realpath.php#84012 . After getting the full file path, ZipArchive::getFromName() will be able to find the file you're looking for.