Consider adding Open Graph metadata to astropix pages

[lyeager]

The Open Graph protocol (https://ogp.me/) is a web standard which makes it easier to parse web pages. If APOD added these metadata tags to astropix pages, then it would be easier for others to parse the page. For example, any astropix URL posted to a Slack channel would be automatically parsed and a nice preview of the page would be attached:

Specifically, we are looking for oEmbed and Twitter Card / Open Graph tags.
https://api.slack.com/robots

Here is an example of a website which implements this protocol:

Code: Select all

$ curl -s 'https://www.imdb.com/title/tt0112384/' | grep 'meta.*property.*og:'
<meta property="og:url" content="http://www.imdb.com/title/tt0112384/" />
<meta property='og:image' content="https://m.media-amazon.com/images/M/MV5BNjEzYjJmNzgtNDkwNy00MTQ4LTlmMWMtNzA4YjE2NjI0ZDg4XkEyXkFqcGdeQXVyNjU0OTQ0OTY@._V1_UY1200_CR89,0,630,1200_AL_.jpg" />
<meta property='og:type' content="video.movie" />
<meta property='og:title' content="Apollo 13 (1995) - IMDb" />
<meta property='og:site_name' content='IMDb' />
<meta property="og:description" content="Directed by Ron Howard.  With Tom Hanks, Bill Paxton, Kevin Bacon, Gary Sinise. NASA must devise a strategy to return Apollo 13 to Earth safely after the spacecraft undergoes massive internal damage putting the lives of the three astronauts on board in jeopardy." />