Fix: content-negotiation when fetching dataset from url

[Falx]

📁 Related issues

#1039

✍️ Description

The reasoning behind this fix was to only use rdf-dereference when the input type is string. That is where the error seems to occur, other flows seem fine. (I might be wrong though)

✅ PR check list

Before this pull request can be merged, a core maintainer will check whether

• this PR is labeled with the correct semver label
  • semver.patch: Backwards compatible bug fixes.
  • semver.minor: Backwards compatible feature additions.
  • semver.major: Breaking changes. This includes changing interfaces or configuration behaviour.
• the correct branch is targeted. Patch updates can target main, other changes should target the latest versions/* branch.
• the RELEASE_NOTES.md document in case of relevant feature or config changes.

[joachimvh]

The integration tests succeed so that means that the code actually works. The unit tests are going to fail though because of the changes. The big one is that it is now trying to do actual HTTP requests instead of mock requests. You'll have to mock the rdf-dereference library now instead and probably do a few other changes there as well https://github.com/solid/community-server/blob/5e0f2e1e9582de6f853f60428ca086bccdff178c/test/unit/util/FetchUtil.test.ts#L8

[joachimvh]

The error message made me realize where the problem is. I pulled the branch and verified the suggested changes work. There is still a test error but it's not related to the mock/types any more. My suggestions can probably also be cleaned up a bit if needed.

[Falx]

I think it looks good now.

[Falx]

Force pushed the new changes

[joachimvh]

Some minor issues remaining.

[joachimvh]

Some very minor style nitpicks, will merge after those.

[Falx]

That should do it then

[joachimvh]

Looks good, thanks!