Could you please provide an HMAC calculator on the site which allows us to enter in all of the fields necessary and then show the output of the couple of steps and the final result? I am hoping this would help me debug things.
I got the HMAC calculation to work once with a mostly hard coded test. Now as I am modifying the code to make it functional the HMAC has stopped validating twice now and I'm not changing the calculation, just the data going into it. I can' think of why it stopped working. Last time I gave up after several hours and just reverted my code to the previous version where it was working and started over adding changes slowly but it stopped validating again and I have no idea why.
You would think this really shouldn't be that hard once you get the HMAC function working it shouldn't stop working as it is a simple formula. It would be nice to be able to verify it against a reference calculator instead of going through the whole order process just to find out it failed and no reason why.
I've tried to compare my HMAC to what you can generate on the doc pages but the way it is set up we don't have control over each item and it is hard to pull each item out of the website and use in our HMAC calculator to compare.