What is the fastest way to determine if a URL exists in PHP?

Question

I need to create a function that returns if a URL is reachable or valid.

I am currently using something like the following to determine a valid url:

Answer 1

You'll likely be limited to sending some kind of HTTP request. Then you can check HTTP status codes.

Be sure to send only a "HEAD" request, which doesn't pull back all the content. That ought to be sufficient and lightweight enough.