How to client/server game using Google App Engine (Looking for tutorial.)

Question

(NOTE: This is a duplicate of a question I asked on SO, having temporarily forgotten about GameDev <hang head in shame>. When one is answered, I will link it back to the other.)

I'm trying to do my first client/server game using Google Apps Engine as my back end (specification requirement.) I've done the tutorials (Java), but that all seems highly browser-centric.

Basically, I'd like my (mobile, not that it matters) app to:

• Allow the user to create a game-account (NOT their Google account!)
• Log-in with that account.
• Press the "MARCO" button to send an account-identified request to the server.
• Get a "POLO" response from the server.
  • As data (like a JSON object, XML-DOM or similar), not as a web-page.

Can anyone point me to a good tutorial/sample project/detailed reading to help me achieve that? I'm pretty sure that, once I get that working, I can do all the rest of it -- but I'm having the "stuck at the starting gate" problem, not being able to work up basic account-login, and non-HTML data exchange.

Thanks!

Answer 1

I have a working example of a client/server game built on App Engine. You can fork it on GitHub and try the live demo.

I haven't written about it or anything yet, but the code is relatively well commented. Have fun!

Answer 2

For something that simple I would recommend using python(and in general the python GAE experience is quite good.)

I am pretty sure that for what you want to do the simple app engine tutorial and documentation woud be enough. You want to create an application that has 3 controllers( check credentials, create credentials and answer marco-polo).

There are a bunch of open source examples of python code for the app engine in github, and a lot of documentation on the official site, i would say go try it out and if you run into a wall ask a specific question =D

Hope that helps!

Answer 3

The part that wasn't clicking for me -- and, as I suspected, was very very simple -- was that it's just a matter of implementing the doPost() (or doGet(), but I use POST) routine, and write back to the responder.

There were also some bits that I didn't follow quite correctly the first time about setting-up the responder class-names and URLs, in the web.xml file (in the war folder.)

Once I got that (web.xml) set up correctly, then the doPost() routine was simply something along the lines of:

public void doPost(HttpServletRequest req, HttpServletResponse resp)
  throws IOException {
    String reqTypeStr = req.getParameter("reqType");
    if (reqTypeStr.equalsIgnoreCase("marco")
        resp.getWriter().println("Polo!");
    else
            resp.getWriter().println("huh?");
}

There are myriad other details but those were the two that hung me up the most. Once I broke that simple barrier, everything else flowed together very quickly.