How does the implementation of link preview on the site look like?

Question

HTML

Good afternoon,
I ran into a problem. It is necessary to implement link preview on the site, as it is done in What's Up. For example, loading a link to a question in a toaster - a preview opens with a picture of the toaster and the title of the question.
The question is, how does this mechanism work, how can it be built into your own website?
Maybe there is a gem for ruby ​​on rails.
thanks for answers

Answer 1

We load the link, send a request to this address, analyze the opengraf markup, display the result. Something like this ))