Bit of a theoretical one here as I'm currently searching for a way to ensure that websites I have worked on always show the version that I created or if they are not available, revert to a localized version.
So, for example, I developed a few sites back in 2009 that have since been re-designed or re-implemented by the client meaning that the work I link to on my portfolio page is no longer the original I developed. I have therefore been searching as to whether it is possible to create a hyperlink on my portfolio that when clicked runs a script that goes away and checks the content of an external page to see if the content
<meta name="author" content="JME" />
for example. However, if this is not present in the meta data then the link should instead revert to a localized version of the initial template I developed to ensure my work is still showcased.
Is there a way of querying the external metadata using PHP so that this type of workaround can be implemented?
It's possible: open the external site, do a get_meta_tags(), look for the existence of the tag. It's not a good idea to do this every time the page is called, though - it would be so slow it would very likely annoy your visitors.
A frequent check (say, once a week) using a cron job would be the best way to go.