Worker-enabled link does not generate a thumbnail


#1

We are sharing a link in linkedin chats. But linkedin does not generate a thumbnail for the links when the links has CF Worker activated (i.e., when the HTML is served by the Worker)…
It works (thumbnail is generated) when Worker is disabled, and HTML is served directly from the origin.

Origin link: https://storage.googleapis.com/cdn.webautomation.tools/templates/prefilled.html

Worker fetches the origin link and serves the response.

When sending our worker-enabled link to linkedin chats, it DOES NOT generate a thumbnail. But sending the origin link (https://storage.googleapis.com/cdn.webautomation.tools/templates/prefilled.html) generates a thumbnail.

What could possibly cause linkedin to not generate link-preview or thumbnail for links that go through Worker?


#2

Hi @user5691,

Sorry, but I’m having difficulty imagining any way that this could be caused by Workers, unless your worker is modifying the response in some way that causes LinkedIn to behave directly. Clients have no way to know that you are using Workers – to them, the response should look like any other returned through Cloudflare.

I would suggest using curl -v to investigate the exact response headers and content with and without Workers enabled to see if you can find any differences that might be affecting LinkedIn’s thumbnail generation.


#3

Oh, I notice your “original link” is not on your own domain, but on storage.googleapis.com. So it’s not just that you enabled Workers, but that you are comparing between your own domain on Cloudflare vs. Google’s entirely separate domain.

I don’t know exactly how LinkedIn generates thumbnails but I know that social networks have a lot of weird heuristics that take effect. For example, I recall discovering once that Twitter has some sort of reputation system for domains, where it won’t show thumbnails for a new domain until it has been vetted in some way (I don’t remember the details).

I also remember that Twitter and Facebook have special developer tools for debugging these things – maybe LinkedIn does too.

I would recommend you take a look at LinkedIn’s documentation and tools to see if you can find out why it won’t serve thumbnails from your domain.

Unfortunately, this is almost certainly not an issue on the Cloudflare side so we probably cannot offer much help here. :confused: