OpenSlide bytes object

[linatakemaru]

Operating system

Platform

OpenSlide Python version

1.1.2

OpenSlide version

3.4.1

Slide format

SVS

Issue details

I have SVS files stored on a Google Cloud Storage server, and would like to reference these files without creating a local copy of the object. To do this, I've successfully read the object as a stream and converted it from a BytesIO object to a bytes object using object.getvalue(). However, when I pass this bytes object into openslide.OpenSlide(bytes_object), I get the OpenSlideUnsupportedFormatError. From the documentation, it sounds like a str, bytes, or PathLike object is accepted, but I can't seem to get it to work. Any help is appreciated, thank you!

[bgilbert]

The bytes object accepted by openslide.OpenSlide() is the path to the file, pre-encoded to bytes. This is useful for bypassing the default str -> bytes conversion if the filesystem path isn't encoded as UTF-8.

OpenSlide requires slide files to be accessible in the local filesystem. You could try mounting a FUSE filesystem that exposes Google Cloud Storage objects as local files. Without fairly aggressive prefetching and caching, though, you may find the I/O performance to be unacceptable.