Here is my codes.
[![debugcode][1]][1]
I am working on buy. And I completed most of the functions. When I go to webServer to test it. I got a fatal error.(because I am debugging the code, so I  commented all the core code.)
[![buy][2]][2]
As you can see, I can get the buy page correctly. But when I post the request, I got this.(It directly logout.)
[![return][3]][3]
It's very strange. I don't know why. And I can't see '666666' in my command console. I think it means that the programme doesn't go into "POST" set.
I want to know how to solve that. Thanks!
  [1]: https://i.sstatic.net/1Cmve.png
  [2]: https://i.sstatic.net/0f4rj.png
  [3]: https://i.sstatic.net/AM1F9.png