Internal Calendar & other links do not preview.

[samuk]

When posting links to Humhub calendar entries into Humhub spaces there is no preview.

When posting links to (public) Humhub posts into spaces there is no preview.

[marc-farre]

The problem seems to be on all Humhub instances (tested with 3 different Humhubs and with public contents that can be viewed without login).

/linkpreview/index/fetch returns the error "Title cannot be blank.":

{url: "https://my-humhub.tdl/s/space-name/calendar/entry/view?id=14",…}
output: {og:site_name: null, og:title: null, og:description: null, og:image: [], og:type: "website",…}
errors: ["Title cannot be blank."]
0: "Title cannot be blank."
og:description: null
og:image: []
og:site_name: null
og:title: null
og:type: "website"

The the <title> tag is present and not blank. Or maybe it's another title? I didn't investigate more.

[aaukt]

AFAIR the old version had a fallback to use the <title> attribute if the og:title metadata was missing (and maybe also thesame for the description). The new version does not have that fallback. Technically this seems to be correct as https://ogp.me/ doesn't list the title as optional. So sites without any opengraph metadata or missing title won't work anymore.

[samuk]

So should this issue be re-framed as 'Humhub should have opengraph metadata'? Is that the problem?

This should be closed and this ticket humhub/humhub#3506 worked on?

[aaukt]

For public available posts humhub/humhub#3506 would solve the problem i think.

For posts behind login it wouldn't help. For that i would prefer if 403 errors/redirects would not be parsed at all.
If you want a preview for internal links it might create a security issue if the preview module could access anything.

[samuk]

In my case all links are public. I'll see if I can get anyone to work on #3506

[luke-]

https://github.com/humhub/linkpreview/issues/8