I'm looking for a way to read specific files from a rar archive into memory.  Specifically they are a collection of numbered image files (I'm writing a comic reader).  While I can simply unrar these files and load them as needed (deleting them when done), I'd prefer to avoid that if possible.
That all said, I'd prefer a solution that's cross platform (Windows/Linux) if possible, but Linux is a must.  Just as importantly, if you're going to point out a library to handle this for me, please understand that it must be free (as in beer) or OSS.
The real answer is that there isn't a library, and you can't make one.  You can use rarfile, or you can use 7zip unRAR (which is less free than 7zip, but still free as in beer), but both approaches require an external executable.  The license for RAR basically requires this, as while you can get source code for unRAR, you cannot modify it in any way, and turning it into a library would constitute illegal modification.
Also, solid RAR archives (the best compressed) can't be randomly accessed, so you have to unarchive the entire thing anyhow.  WinRAR presents a UI that seems to avoid this, but really it's just unpacking and repacking the archive in the background.
Read content of RAR file into memory in Python