Detect connection speed by loading time

fabiuz

Hi,

I am looking for a way to detect users connection speed on my pages.

What I want is to determine if a user is connected by a ISDN, 56 kb or slower connection modem or by a fast DSL line.

In order to do this I was thinking about put a 30 kb image or file to be read by the user browser and save time needed to load the complete page (or image) understandig if it is a fast or slower user by the time needed.

Do you think it is possible to do something like that ?

For now I am trying somthing like:

header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
// HTTP/1.1
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
// HTTP/1.0
header("Pragma: no-cache");

function exec_time() {
$mtime = explode( " ", microtime());
$msec = (double)$mtime[0];
$sec = (double)$mtime[1];
return $sec + $msec;
}

$start = exec_time();

include 'http://www.canzoni.it/peso.php';

// where peso.php = <img src="img/speedtrap.jpg" width="470" height="45">

$stop = exec_time();

but is seems not to work because I think stop is executed before the image is loaded.

I was thinking to something like:

file_get_contents

but I think it is not good because it will work locally on server.

Any suggestions about ?

Thank you very mych !

weekender

i don't think this is a php problem, as php is server-side. You need a client-side language (ie javascript)

go with the same process, but start the timer using the BODY BEFORELOAD attribute and finish it with the ONLOAD attribute, then calculate the time taken to load the page and go from there.

AstroTeg

Someone may have a clever idea, but I'm thinking this isn't going to be easy to do. The problem is you build a page to feed the content back to the browser and you're using PHP to build that page. Once PHP finishes building the page, the web server (usually Apache) then goes ahead and takes PHP's output and dumps it down the network wire and to the browser. As far as PHP and Apache are concerned, the page is gone and no longer a concern. If the user's browser loads it, great. If it takes two days to load it, its their problem. I don't even think page load times are even available in the web logs.

If you check out some of the speed testing tools online, they're usually done in Java. Java is able to open a network connection on the client machine. Once opened, it can keep track of the amount of time it takes to send and receive data (and the data is just junk - but a rather large chunk like 1mb or so). After the transfer is completed (either uploading or downloading), Java can look at the transfer's start time and stop time and with a little math, figure out the transfer rate.

You would almost need to setup a socket server of some sort to have send the image down and track how long it takes the browser to take it all in. But if the images are only 30k, you're going to have some really skewed results. With shared DSL/cable connections, you can have a very fast connection one minute and a very sluggish connection the next.

AstroTeg

JavaScript is definitely an option. The only trick is you'll also be calculating the PC's processing speed as well. If they have 20 apps open and a high speed connection, it could still take a little bit of time to render the page and you won't get an accurate idea on bandwidth.

weekender

ahh but surely you want to take this into account. If you're testing bandwidth, it's probably for a site containing high-multimedia usage. And for this, you want the actual bandwidth rather than the maximum capable bandwidth.

If you have a 512kbps connection, but due to a slow system or many apps open you only get 192kbps, you want to reflect that in the pages served.