fopen, fwrite, but only if newer, or different

[zdislaw]

Hi,

I've got a simple dealy-bob that opens a remote file, and writes it to a local file.php include. What is the recommended best way to not have the contents of the include written, or the source file grabbed unless the content is new? They only change once a day or so and I don't want to hit the remote server on every page load.

I don't have access to crons on my server or I'd just have the script run once every few hours or so.

So I'm thinking I should either:

A. Compare the timestamp on the remote server page before doing my fopen with timestamp from the last fopen (somehow...I have no idea how to do this yet). Then go ahead with the fopen if they are different.

or

B. Compare the local file timestamp when I go to write it. This won't help load on the remote server but will let me only write the file locally if it's new. It this even worth it? Or should I just go ahead and write the local file each time?

$content = "Stuff I pulled from a remote server";
$archive = "/home/www/includes/file.php";
$writepointer = @fopen($archive, "w") or die("Error! Can't open file.");
@fwrite($writepointer, $content) or die("Error! Cant write to file."); 
fclose($writepointer);

Thanks!!

Zdislaw

[devinemke]

either way you are hitting the remote server, whether you are grabing the file contents or just checking the timestamp.

solution A: I don't believe filemtime() will work on remote files (but I think this is changing in PHP 5.0) so if you want to check the modification timestamp of a remote file you would have to open a socket connection using fsockopen().

solution B: If you are going to go ahead and grab the file regardless you can check to see if it has changed by spooling both files into strings using file_get_contents() and simply doing:

if ($remote_contents != $local_contents) {write the remote contents to the local file}
else {echo 'file are the same';}

[swr]

You might want to use filemtime on your copy, and if it is older than a certain age, pull the latest version from the other site.

That way you'll be reasonably current without having to hit the other site every time, and without having to run a cron job type thing.