t is quite convenient to use the Google App Engine to act as a Path Forward Application. A "Path Forward Application" forward the request to target webserver, making it acting just like the target web site.
Actually, a "Path Forward Application" fetch the content of corresponding url in the target site together with the essential request parameters and return back the result to user. For Detail, please see http://app-engine-guide.buss.hk
For discussion of the code, see here