Bug Solving for a Google Apps Script

I am a Google Apps Admin. I have written a Google Apps Script (just 200 lines with most are authorization parts and comments) to receive change notifications from users' drive but need bug fixing. Its core parts are: Authorize as Server's "Service Account" (so as to perform Domain-Wide Delegation of Authority) + [login to view URL]() to post notification to [login to view URL]" + doPost() to receive notification If you are interesting in this job, your job is to let my doPost() successfully receive notification. Source code is here: [login to view URL] When you propose, please mention when will you finish. Reference: I think the main problem is: doPost() is blocked by the Authorization of Google [login to view URL] pass through it, it need to run Server's "Service Account" authorization, but my code is failure in this part at least. If you are experienced with setting up "Service Account" and doPost() in Google Apps Script for Google Apps, then you will know my script problem immediately and solve the problem within minutes (I believe bugs exist within a part with 10 lines only). This may be totally a syntax problem. If you have no experience but want to take this challenge for learning, I am still welcome. However, delivery time should still be reasonable. Above is for your reference only. The successful of your job is counted by letting the doPost() to successfully receive notification.