nextcloud: direct pre-signed download link

[ser]

This PR extends S3 configuration with a use_presigned_url introduced in Nextcloud 33 with nextcloud/server#54436

Things done

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

[ser]

please review.

@bachp

@britter

@Ma27

@provokateurin

[provokateurin]

I think adding an assertion for the case where this is enabled on versions before 33 makes sense.

[ser]

I think adding an assertion for the case where this is enabled on versions before 33 makes sense.

Added! Thanks.

[provokateurin]

Suggested change

	|| cfg.config.objectstore.s3.use_presigned_url != null;
	|| cfg.config.objectstore.s3.use_presigned_url == null;

Should be like this no? Either the version is 33.0.0 or higher or the option must be empty for everything to be fine.

[ser]

I really do not know why I included the second line in assertion, I have removed it completely now and left the essential part.

[provokateurin]

No you need to keep it, because also support older versions. So just apply my suggestion and then it should be good.

[Ma27]

@provokateurin how hard would it be to extend the VM test to make sure it's properly serving pre-signed files? I imagine you'd have to upload a file and obtain a download link?

If it's reasonably doable, I'd really like to see test-coveratge for it.

[ser]

If it's reasonably doable, I'd really like to see test-coveratge for it.

the verification procedure is described here:
nextcloud/server#54436 (comment)

[provokateurin]

how hard would it be to extend the VM test to make sure it's properly serving pre-signed files? I imagine you'd have to upload a file and obtain a download link?

Should be easy, the link is just a WebDAV prop that can be queried.

[ser]

Despite of installing a patched version of Nextcloud with this PR and enabling the presigned urls, I am unable to see them, unfortunately.

I am getting empty values: <oc:downloadURL></oc:downloadURL><nc:download-url-expiration></nc:download-url-expiration>

[Ma27]

Anything interesting in the error logs?

[ser]

Anything interesting in the error logs?

No, nothing special. I set the loglevel to 0 to be sure, but there is nothing suspicious, the request is served normally, the file is found correctly.

[ser]

I have installed a Nextcloud docker and I get the same issue, so it's not related to the NixOS packaging. I am investigating it further for a likely Nextcloud bug.

[ser]

I filed nextcloud/server#59249 but it does not seem to a prority for the nextcloud S3 team