Equivalent is_file() function for URLs?

Question

What is the best way to check if a given url points to a valid file (i.e. not return a 404/301/etc.)? I've got a script that will load certain .js files on a page, but I need a way to verify each URL it receives points to a valid file.

I'm still poking around the PHP manual to see which file functions (if any) will actually work with remote URLs. I'll edit my post as I find more details, but if anyone has already been down this path feel free to chime in.

Answer 1

one such way would be to request the url and get a response with a status code of 200 back, aside from that, there's really no good way because the server has the option of handling the request however it likes (including giving you other status codes for files that exist, but you don't have access to for a number of reasons).

Answer 2

If your server doesn't have fopen wrappers enabled (any server with decent security won't), then you'll have to use the CURL functions.

Answer 3

The file_get_contents is a bit overshooting the purpose as it is enough to have the HTTP header to make the decision, so you'll need to use curl to do so:

<?php
// create a new cURL resource
$ch = curl_init();

// set URL and other appropriate options
curl_setopt($ch, CURLOPT_URL, "http://www.example.com/");
curl_setopt($ch, CURLOPT_HEADER, 1);
curl_setopt($ch, CURLOPT_NOBODY, 1);

// grab URL and pass it to the browser
curl_exec($ch);

// close cURL resource, and free up system resources
curl_close($ch);
?>