Why does FB sharer use only the OG meta tag detail

问题:

I have a project, coded on codeigniter, which is basically a collection of posts by different users. While adding the fb share button and clicking on it, The image, title and description content is taken from the header of the home page and not of the page(view) where the share button is placed?

回答1:

As mentioned here, The issue was that only those users could view the page who are signed in, and therefore even fb wasn't able to scrape the info from there.

EDIT: Whats important here is how FB scrapes the info. Apparantly the link you provide inside data-href if parsed by FB and they capture the og meta tags from the header on that page. However if you restrict those pages to logged in users, FB is also unable to parse the page and thus it reverts to the base URL's meta tags.