Using a Shipping Company API - MOD PLEASE MOVE to DEVELOPMENT

[dish_x]

Hi everyone,
I'm attempting to implement a shipping calculator into my website (www.oz-audio.com.au) however it seems to be a lot more complicated than I thought.

Here's some info the shipping company sent to me regarding the API:

Call Method:
Requests are passed to Transdirect via HTTP GET method, essentially via the URL. The URL to pass
the variables to is http://www.SHIPPINGCOMPANY.com.au/calculator/return_quote.php

The variables are:
from - Numeric, 4 digits The postcode of the pickup location
to - Numeric, 4 digits The postcode of the delivery location
length - Numeric, 1-3 digits The length of the item, in cm
width - Numeric, 1-3 digits The width of the item, in cm
height - Numeric, 1-3 digits The height of the item, in cm
weight - Numeric, 1-3 digits The weight of the item, in kg
quantity - Numeric, 1-3 digits The quantity of this item.
id - Numeric, 1-5 digits Membership ID number
Example:

If we were shipping from postcode 3000 to postcode 4000 and had two items:
first item is 7 x 12 x 15cm, 35kgs
second item is 22 x 15 x 10, 27kgs

www.SHIPPINGCOMPANY.com.au/calculator/return_quote.php?from=3000&to=4000&quantity;[]=1&length;[]=7&width;[]=12&height;[]=15&weight;[]=35&quantity;[]=1&length;[]=22&width;[]=15&height;[]=
10&weight;[]=27&member=40

Now there are a few things I would need to do in order to achieve this correctly..

Firstly I would need to assign dimension values to the products, and the easiest way to go about this is to use standard dimensions for each category (For eg: all the products in 'Head Units' category would have 30cmx30cmx40cm)

I was then thinking I would need to create a function (or modify an existing function) in site/classes/Carrier.php
Would it be possible to modify the function 'getDeliveryPriceByWeight' or create a new one that would execute the following commands whenever a shipping estimate is called for

1. Declare 'shippingString' as String = "http://www.SHIPPINGCOMPANY.com.au/calculator/return_quote.php?from=3000&to;=" + Get current logged in customer post code

2. Check if there is products in the cart
     If true, then loop this for each product in cart:

         2a. Declare length, height, width, quantity as string
         2b. Determine product box dimensions based on category (get product category id, if category id = "Head Units" then length = 30, height = 30 and width = 40) and quantity = quantity in current cart
         2c. shippingString = shippingString + "&quantity;[]=" + quantity + "&length;[]=" + length + "&width;[]=" + width + "&height;[]=" + height + "&weight;[]="

3. After all products in cart have been looped through, append the shippingString:
   shippingString = shippingString + "&member=40"

4. Execute an HTML GET with the data in shippingString

5. Display the result (should either be a numeric value, or an error message)

Apologies for the crappy pseudo-code but hopefully that explains what I would like to achieve
Currently running Prestashop 1.3.3

If anyone could help or has relevant experience/advice I would greatly appreciate it

Thank You

Dish