Manipulate an Archive in memory with PHP (without creating a temporary file on disk)

I am trying to generate an archive on-the-fly in PHP and send it to the user immediately (without saving it). I figured that there would be no need to create a file on disk as the data I’m sending isn’t persistent anyway, however, upon searching the web, I couldn’t find out how. I also don’t care about the file format.

How to add/update a file to an existing tar.gz archive?

Is there a way to add/update a file in a tar.gz archive? Basically, I have an archive which contains a file at /data/data/com.myapp.backup/./files/settings.txt and I’d like to pull that file from the archive (already done) and push it back into the archive once the edit has been done. How can I accomplish this? Is it problematic because of the . in the path?