How to evenly split traffic between two pages - php

Question

Purely hypothetical at this point, no code yet. Trying to figure out the best way to do this. We are company "A" and we have two partners, company "B" and company "C". On a sign up form, we collect data and then pass it on to either partner "B" or parnter "C" - this part is good to go and working fine. I do this with ajax on the front end and a cURL processor on the back end so no one leaves our site and just post the data directly to the partner's form.
Unfortunately due to partner "B" and "C"'s required data the forms we post to are different and we have to have 2 separate html form files, one for each partner. The problem is that we need to do this all from one URL, not a separate one for each partner.
I would guess we would use a 'handler' page that has the specific url - http://www.example.com/parterForm.php
Then in the 'handler' page we would make the switch serve the correct content. I need a way to evenly split who we send data to. I'd like to do the switch on a very granular, MS level for example:
if the time = 0-500 ms - serve Parter B page;
if time = 501-1000ms -serve Partner C page;
all done within the 'handler' page - calling the forms as php includes?
I realize this is not a specific code question and I aplogize, this is something I've never done before and am trying to figure out how to do this. I'm a Creative Director btw who codes, no other resource avail.
thanks.

Answer 1

Hmm, yes, you could do that. That would work reasonably well, in fact. The important thing is to make sure the form goes to the right partner. You could use $_SESSION for that, or check which fields were sent and deduce from that which partner was chosen.
For example:
if( fmod(microtime(),1) < 0.5) include("forms/partner1.php");
else include("forms/partner2.php");
Then when submitted:
$partner1fields = array("name","email","country","dateofbirth");
$partner2fields = array("name","address","postcode","ethnicity");
// the above are examples - they should correspond to the $_POST keys you expect
// now check if they match. Array equality depends on order, so sort first
$postkeys = array_keys($_POST);
sort($postkeys);
sort($partner1fields);
sort($partner2fields);
if( $postkeys == $partner1fields) { /* submit to partner 1 */ }
elseif( $postkeys == $partner2fields) { /* submit to partner 2 */ }
else {
echo "<p>Given keys did not match either partner</p>";
echo "<p>POST keys: ".implode(", ",$postkeys)."</p>";
echo "<p>Partner 1 keys: ".implode(", ",$partner1keys)."</p>";
echo "<p>Partner 2 keys: ".implode(", ",$partner2keys)."</p>";
echo "<p>Please report this error to the site administrator.</p>";
exit;
}

Answer 2

First, by MS I assume you mean the latency between client and server?
Use javascript to either load a tiny image from the server or make an ajax call that gets one char or something and time this. For testing you'll need to do some real pings and adjust your js time to reflect the ping round trip. For example, if the js time to load the image is 500ms but ping time is only 80ms then maybe divide by 6 for the result. This will never be very precise as the client and the server both have processing overhead. Make sure to echo no cache headers or past expire times with the image or ajax response.
Easy, if time <= 500 redirect to form A, if time > 500 redirect to form B or use ajax to load them up.