Error downloading STAC asset: Protocol "s3" is unknown (QGIS 3.40)

[robbibt]

What is the bug or the crash?

Downloading assets from the following Digital Earth Australia STAC catalogue (https://explorer.dea.ga.gov.au/stac) on QGIS 3.40 produces the following error:

Steps to reproduce the issue

On QGIS 3.40:

1. From Settings > Options > System > Environment, ensure that AWS_NO_SIGN_REQUEST=True environment variable is set (restart if necessary)

2. Add "https://explorer.dea.ga.gov.au/stac" as a new STAC Connection called "DEA STAC catalogue"
3. In the STAC browser menu, navigate to "ga_s2ls_intertidal_cyear_3" collection
4. Right-click on the first STAC item, and click "Download assets"

5. Error will appear:

Versions

QGIS version	3.40.0-Bratislava
QGIS code revision	b56115d874
Libraries
Qt version	5.15.13
Python version	3.12.7
GDAL/OGR version	3.9.3
PROJ version	9.5.0
EPSG Registry database version	v11.016 (2024-08-31)
GEOS version	3.13.0-CAPI-1.19.0
SQLite version	3.46.1
PDAL version	2.8.1
PostgreSQL client version	unknown
SpatiaLite version	5.1.0
QWT version	6.3.0
QScintilla2 version	2.14.1
OS version	Windows 10 Version 2009
Active Python plugins
latlontools	3.6.20
mmqgis	2021.9.10
Qgis2threejs	2.7.3
QGISSortAndNumber-master	1.0
qgis_stac	1.1.2
raster_cutter	0.6.1
valuetool	3.0.19
MetaSearch	0.3.6
processing	2.12.99

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

This appears to be caused by our STAC metadata providing links to our assets as S3 URIs vs https:

To my knowledge this is a common use case for STAC metadata pointing to data stored in AWS S3 - it would be great to allow downloads for these kinds of href links.

Example STAC metadata document:
https://explorer.dea.ga.gov.au/stac/collections/ga_s2ls_intertidal_cyear_3/items/6ef7df62-b507-494e-a3ba-e39194309972

[robbibt]

FYI, this issue also affects the external QGIS STAC plugin:

• Plugin does not load assets with href starting with s3:// stac-utils/qgis-stac-plugin#215
• Error in downloading file, Download failed: Protocol "s3" is unknown stac-utils/qgis-stac-plugin#221
• Support adding assets with s3:// protocol stac-utils/qgis-stac-plugin#242

With a proposed/unmerged fix here:

• Support for GDAL related assets stac-utils/qgis-stac-plugin#218