strange file issue

olaf

Hallo,

i use the following code for a visit-counter:

$countFile = "count.txt";

$fileHandle = fopen($countFile, "r");
$counter = (int) fread($fileHandle, 20);
fclose($fileHandle);

if(!isset($cookCount))
{
setcookie("cookCount", $counter, time()+7200);
$counter++;
}

echo $counter; //counter value
$fileHandle = fopen($countFile, "w");
fwrite($fileHandle, $counter);
fclose($fileHandle);

The first time was several month before the counter was set to 500 after ~45000. I changed the number and put in a .htaccess file into the folder. Now 6 weeks later it was again now reset to 10000. What is the my problem here? Please don't suggest an other way for counting visits (i know that this is not the best way) Thanks.

majik-sheff

How busy is your site? If you have more than one request come in simultaneously for the same count file you will usually get very strange results. You end up with multiple instances of PHP opening the file and saving at different times.

As the site gets busier, the results will get stranger. If you must use this method of count tracking you will need to introduce some form of file locking mechanism. Unfortunately, this complicates your code almost exponentially.

olaf

Ok,
i can follow you but the site haves not more than 50-100 visits each day... are there other possibilities?

majik-sheff

Are you doing any error checking on the fopen operations?

If you get even one failed open for read your resulting integer will be 0, which could then subsequently be written to the file as a 1 after it's incremented.

It's a very good habit the write your code as:

if ($fileHandle = fopen($countFile, "r")) {
     //Code goes here
} else {
     //Error handling
}

If you don't have PHP error logs available, you can have your error code append info to a file of your own. This tells you where your operations are failing, and as a side-effect it prevents the failure from hosing your counter file.

olaf

you are absolutly right this is very simple (bad) counter. I use this counter on page with more 1000 visits sinds more then 1 year on the same server. I think it's better to remove the script....

I asked because i thought there something other unsafe...

majik-sheff

Only unsafe in the sense of not having any error detection/correction. 🙂

olaf

thanks for your help... but i can't believe that's because two visitors open the file at the same time...

majik-sheff

Sorry, it's all I have 🙂 Maybe someone else has a suggestion.

olaf

i hope so...
:bemused: