I was excited when I read Google had released an API for their Affiliate Network, as I wanted to automate pulling sales data from GAN. But I quickly became disheartened when I realized how difficult it is to use.
Since this was for myself, and not a web-based service that would be used by others, the Simple API method of authorization was good enough. After getting it to work with Picasa, but not GAN, I asked for some help and was introduced to the OAuth 2.0 Playground. This showed me the headers I’d need to send, and how OAuth 2.0 works.
For the record: the Google Affiliate Network API does NOT support Simple API Access. You cannot access the service with an API Key and IP locking.
I now have a working script, and have written up step-by-step instructions on how you can pull orders from GAN automatically each day.
This script is not complete, as it’s up to you to do something with the data once you have it. You can also modify the final call to pull advertisers, instead of orders.
After reading an 
After nearly three months of on & off coding, banging my head against the table and thumbing through the 