Implement /preview_url

[r3k2]

Background information

• Dendrite version or git SHA: Your branch is up to date with 'origin/main'. git sha: 6c95f9b535191bc28cb983a6fa0eab036dc40916

• Monolith or Polylith?: Monolith

• SQLite3 or Postgres?: postgresql

• Running in Docker?: Hell no.

• go version:

go version go1.18 linux/arm64

• Client used (if applicable): Element-web Element-Desktop Gomuks(but this is not related since is console base but it does supposed to render in ASCII)

  Description

After almost 2 years running dendrite I never really got the rss/link/images previews no matter how many times I enable it on element-web or element-desktop etc since this is not a big deal and have other bigger issues to fix I never brought it up. Who is affected all my users on our dendrite server.

I do not see any logs that will output or spit anything related is just ignored. I enabled and disable a couple times the render images option to see if it help, today I did again with no luck.

Steps to reproduce

Someone post a URL and on matrix.org I can see the preview but on my dendrite user account I can not. Same with bots and anything/anyone that pastes a url or anything to preview.

I am in contact with Keg over matrix but for bigger issues, he has access to my server if needed for troubleshooting.

[kegsay]

We don't have /preview_url support in yet I think - https://spec.matrix.org/latest/client-server-api/#get_matrixmediav3preview_url

[NickCao]

We don't have /preview_url support in yet I think - https://spec.matrix.org/latest/client-server-api/#get_matrixmediav3preview_url

Is this in the roadmap?