Checking File Exists..

[Krakken]

I would like to check to see if a file exists on mine or anothers webserver. It's so I can show whether the link is active or down. Thanks.

[Weedpacket]

You want to test URLs to make sure they're not dead links, you mean.

Use [man]fsockopen()[/man] to connect to the server, send a request for the URL (sample code given on the cited page), and make sure the three-digit response code that comes back doesn't start with a 4 or 5, which would indicate an error (E.g., 404 not found or 500 internal server error). The response (if there is one at all; the whole server might be down!) will be on the first line of the header.

[Krakken]

Thanks, how can I check if the server is completely down though and no response is given?

[Weedpacket]

Well, if there's no response then PHP will sit there waiting, waiting, waiting, ... until it gives up. Use set_socket_timeout() to adjust how patient it will be (don't forget to take into account the time limit the whole PHP script has to run under).

Needless to say; this is a slow job and not one you want to do every time you display the page. I'd recommend storing this connection quality info along with the links themselves, and updating it with a script like this on a regular basis.