Displaying image before code

Jon12345

I have the following code:

<img src=http://www.trackingsite.com/cnt/a/12946/ height=1 width=1>
<?php
$ipaddress=$_SERVER['REMOTE_ADDR'];

blah blah...

if(!empty($product)) {echo '<script type="text/javascript">'."window.location.replace('".$product."');</script>";}
?>

Questions:

Is it ok to display the single pixel gif or will that stop the $_SERVER['REMOTE_ADDR']; from picking out the ipaddress?
Will it redirect before the single pixel has time to display?

Thanks,

Jon

bpat1434

The $SERVER array is there no matter what. What you're thinking about is $SESSION array (which is only available after session_start() is called, and that must be called before output).

If it's a single pixel, why even display it? People won't notice it. What you could do is use a setTimeout() on the javascript to have it wait XX seconds to fire. that way you ensure the user "sees" the one pixel.

Jon12345

The image is to fire a tracking script with a 3rd party provider. Therefore it needs to be shown. And the page can't have a delay else the visitor might abort it. Would the image still track?

bpat1434

I doubt it. You could just use a meta tag like:

and that will show the page, and the image, and then redirect them. Not instantaneous, but with a minor delay, they might not notice.

Jon12345

Is that because there is little time before the visitor is redirected from that page and therefore the img link doesn't have time to update?

bpat1434

Well, if you don't delay it, once the script is done processing, the browser will be forwarded to the destination. If there's no "delay" then the image may never be downloaded. If there's a slight delay, then it most likely will send the request for the image before it's told to move on.

One thing you could do is something like:

<?php
/* Let's touch the stat server */
$fh = fsockopen('http://www.trackingsite.com/cnt/a/12946/', 80, $error, $errno, 30);
if($fh) {
  // We're connected, let's send some headers!!
  $out = "GET / HTTP/1.0\r\n";
  $out .= "Host: www.trackingsite.com\r\n";
  $out .= "Connection: Close\r\n\r\n";

  $html = '';
  fwrite($fh, $out);
  while(!feof($fh))
    $html .= fread($fh, 1024);
}
$ipaddress=$_SERVER['REMOTE_ADDR'];

// blah blah...

if(!empty($product)) header('Location: '.$product);

But that's just another option of what you could do. Obviously it needs refinement, and checking to make sure that you get an HTTP header of 200 OK back.

NogDog

You could flush() after the img to try to force the server to send it immediately:

<img src=http://www.trackingsite.com/cnt/a/12946/ height=1 width=1>
<?php
flush();

$ipaddress=$_SERVER['REMOTE_ADDR'];

blah blah...

if(!empty($product)) {echo '<script type="text/javascript">'."window.location.replace('".$product."');</script>";}
?>