PHP Script for PayPal API - Permissions and Express Checkout

I need a PHP script which consists of only one class with functions inside of it to interact with PayPal. This script needs to work with both the sandbox environment and the live environment depending on my choice. I do not need a GUI only the PHP class. Below is a scenario example from PayPal describing their Permissions API functionality. In the explanation below I am the one providing the shopping cart. This is exactly what I need to do as described by PayPal. I am the shopping cart provider. “You provide a shopping cart for merchants and need to make calls to the Express Checkout API to complete payments into the merchant’s account. As a shopping cart provider, you are a third party to the transaction between PayPal and the merchant and, thus, require permission from the merchant to take actions that affect the merchant’s PayPal account. The Permissions Service API enables your cart to request permission to execute Express Checkout APIs on your behalf.” – from: [login to view URL] PayPal provides an SDK which works, See [login to view URL] This SDK has many dependant libraries. As I said before I need to be stripped down and contained only in one PHP class. Then with the information received from PayPal I will need to be able to make Express Checkout API calls for the merchant. So the function here ( [login to view URL] ) would need to be modified so I can perform this for a merchant after they have approved my application. Specifically PPHttpPost would need to be modified. I image the class to work similar to the following examples but my logic might be slightly off but this should help clarify: Hypothetical Examples: $yourpaypalclass->requestPermissions (### APPLICATION VARIABLES AND REQUESTED PERMISSIONS #### ); $yourpaypalclass->PPHttpPost($methodName_, $nvpStr_ ## INFORMATION RETURNED FROM requestPermissions ###) So I will need to be able to - Generate Request tokens for my application to act on behalf of merchants - Send merchant to correct paypal destination with token to approve permissions - Receive response variables when permissions granted - Perform PPHttpPost for merchants from my application after permissions granted All functions should reside in one class. I only need the class, no GUI required. Do not worry about storing the information I just need it returned, I will handle saving it to a database. This is a long explanation but if you understand my request and understand PayPal API this should be extremely easy and cost less than $100.