got Validation of viewstate MAC failed when sending post request from google app engine via url fetch service

Question

I have a task to fetch html from a website, before I go to that page I need to log in.

I use a low-level api url fetch service. Here is my code test code:

Answer 1

Commonly, when you're trying to emulate a postBack on the asp.net, you need to POST:

• preserved from the first request cookies to act on the same session
• data fields (login, password)
• hidden ones from the first page: __VIEWSTATE, __VIEWSTATEENCRYPTED (even if it's empty!), __EVENTVALIDATION
• if you sending some action items, maybe you need to include also hidden fields __EVENTTARGET and __EVENTARGUMENT