Question

I made a hit counter for a web app, but am confused as to why it’s incrementing by two. I simply set a counter variable from the hitCount.txt file, which contains an integer and write the pre-incremented value back to the file.

The code in question:

    // get visit count
    $wag_file = "hitCount.txt";
    $fh = fopen($wag_file, 'r+');
    $wag_visit_count = intval(file_get_contents($wag_file));
    // increment, rewrite, and display visit count
    fputs($fh, ++$wag_visit_count);
    fclose($fh);
    echo $wag_visit_count . $html_br;

Answer 1

I’d say the most logical explanation is that your PHP script is called twice.

Take a look at what’s called by the browser, using for example the Net tab of Firebug.

A typical example is an <img> tag with an empty src : the browser will consider the empty src points to the current page — and reload the current URL.

As a sidenote : instead of reading the file and only then writing it back, you should open your file in read/write mode, and lock it, to avoid concurrent writes — see flock().

Basically, as you are already opening the file in r+ mode, you should use something like fgets() to read from it — and not file_get_contents().