Using OAuth2 Decorator to read and write to Google Sheet, Google App Engine

[lindsay via StackOverflow]

Unfortunately I've been going in circles trying to find a solution for reading and writing to a shared Google Sheet* from my Python based Google App Engine webapp2 application. I have successfully implemented used the OAuth2Decorator to take users through granting permissions to their Google Drive files, but I have had a lot of trouble finding the correct method of reading and writing data to a specific spreadsheet. It's driving me crazy.

I have seen a few examples of people using GSpread to write to a Google Sheet, but it appears that this framework is designed to by run through command line and only write to a spreadsheet that the developer owns. Gspread also appears to be using a different method of validating user credentials rather than using the OAuth2 flow.

I have also looked at using the Google Drive V3 API but the documentation is really confusing to me and it would appear that this API only allows users to edit meta-data or upload or delete files. Not what I'm after. I need to be able to edit the spreadsheet directly not its meta-data.

I'm really just about out of ideas on how to do this. If I've misread any of the documentation on this subject whether it be the GSpread or Google pages, please let me know; otherwise I am more than happy to use any recommended method to achieve the same result.

Any and all suggestions about this would be superb! And thank you very much anyone who has taken the time to read this and may not have an answer.

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http://stackoverflow.com/questions/35955501/using-oauth2-decorator-to-read-and-write-to-google-sheet-google-app-engine