SampleData download is failing on MacOS preview

muratmaga · August 18, 2025, 5:09pm

This has been going on for a while. I am posting here to increase its visibility:

SampleData downloads broken in Mac 5.9 (urllib missing https)

opened 10:40PM - 08 Jul 25 UTC

## Summary In 5.8.1 using the `downloadFile` method from `SampleData` or `slice…r.util` works on Mac, but on 5.9 as of the past few days it has stopped working for https endpoints. Importantly, it works when running `PythonSlicer` but not in Slicer's python console or in scripted modules. Seems to work fine on other platforms too. Note that using the SampleData module to test can be misleading since many developers already have most of the datasets in their caches. Be sure to delete the files if using SampleData to test. (e.g. `rm /Users/pieper/Library/Caches/slicer.org/Slicer/SlicerIO/MR-head.nrrd`) ## Steps to reproduce Run these commands: ``` >>> import urllib.request >>> urllib.request.urlretrieve("https://github.com/muratmaga/E15-Atlas/releases/download/v1/antspy-template.nrrd", "/tmp/a.nrrd") Traceback (most recent call last): File "<console>", line 1, in <module> File "/private/tmp/Slicer.app/Contents/lib/Python/lib/python3.12/urllib/request.py", line 240, in urlretrieve with contextlib.closing(urlopen(url, data)) as fp: ^^^^^^^^^^^^^^^^^^ File "/private/tmp/Slicer.app/Contents/lib/Python/lib/python3.12/urllib/request.py", line 215, in urlopen return opener.open(url, data, timeout) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/private/tmp/Slicer.app/Contents/lib/Python/lib/python3.12/urllib/request.py", line 515, in open response = self._open(req, data) ^^^^^^^^^^^^^^^^^^^^^ File "/private/tmp/Slicer.app/Contents/lib/Python/lib/python3.12/urllib/request.py", line 537, in _open return self._call_chain(self.handle_open, 'unknown', ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/private/tmp/Slicer.app/Contents/lib/Python/lib/python3.12/urllib/request.py", line 492, in _call_chain result = func(*args) ^^^^^^^^^^^ File "/private/tmp/Slicer.app/Contents/lib/Python/lib/python3.12/urllib/request.py", line 1420, in unknown_open raise URLError('unknown url type: %s' % type) urllib.error.URLError: <urlopen error unknown url type: https> >>> ``` ## Environment - Slicer version: Slicer-5.9-2025--07-07 - Operating system: Mac + tested on both amd64 and arm64

Requesting download CTP-cardio.seq.nrrd from https://github.com/Slicer/SlicerDataStore/releases/download/SHA256/7fbb6ad0aed9c00820d66e143c2f037568025ed63db0a8db05ae7f26affeb1c2 ...
Download failed: 
Download failed (attempt 1 of 3)...
Requesting download CTP-cardio.seq.nrrd from https://github.com/Slicer/SlicerDataStore/releases/download/SHA256/7fbb6ad0aed9c00820d66e143c2f037568025ed63db0a8db05ae7f26affeb1c2 ...
Download failed: 
Download failed (attempt 2 of 3)...
Requesting download CTP-cardio.seq.nrrd from https://github.com/Slicer/SlicerDataStore/releases/download/SHA256/7fbb6ad0aed9c00820d66e143c2f037568025ed63db0a8db05ae7f26affeb1c2 ...
Download failed: 
Download failed (attempt 3 of 3)...

Topic		Replies	Views
Sample Data Download failed Support	2	274	November 10, 2023
Error downloading Liver CT sample image Support	7	414	March 11, 2023
Downloaded Sample Data Not Loading Support	1	295	February 9, 2021
Sample Data Load Complete, Still Won't Appear Support	8	551	July 6, 2020
Incomplete Slicer package download - `gzip: stdin: invalid compressed data--format violated` Support web-infrastructure , installation	15	3138	August 23, 2023

SampleData download is failing on MacOS preview

Related topics