ZipArchive Read From Unseekable Stream Without Buffering to Memory

Question

Is there a way to read a zip file from a network stream without buffering it entirely in memory? I'd have liked to avoid downloading the entire file before starting to process its contents to save on processing time.

I'm using .Net Core 3.1

Answer 1

The ZipArchive class as shown here will buffer the stream into memory if it's not seekable. So the only way to avoid buffering large zip files into memory would be to first download the file to the local file system and opening a FileStream which is seekable.

This is because the Directory of the zip, the part of the file that has a list of all the contents and their locations, is located at the end of the file. So the class needs to jump around between different parts of the zip to extract its contents.