I'd guess you're right.
Taking a quick look at the headers between the two links (a la
Firefox):
http://pyamf.appspot.com/crossdomain.xml
GET /crossdomain.xml HTTP/1.1
Host:
pyamf.appspot.com
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:
1.8.1.13) Gecko/20080311 Firefox/
2.0.0.13
Accept: HTTP Accept=text/xml,application/xml,application/xhtml
+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer:
http://groups.google.com/group/google-appengine/browse_thread/thread/6423299aa163134d
HTTP/1.x 200 OK
Expires: Fri, 11 Apr 2008 15:56:50 GMT
Cache-Control: public, max-age=5
Content-Type: text/xml
Server: Google Frontend
Content-Length: 218
Date: Fri, 11 Apr 2008 15:56:45 GMT
---
http://ae.pyamf.org/crossdomain.xml
GET /crossdomain.xml HTTP/1.1
Host:
ae.pyamf.org
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:
1.8.1.13) Gecko/20080311 Firefox/
2.0.0.13
Accept: HTTP Accept=text/xml,application/xml,application/xhtml
+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer:
http://groups.google.com/group/google-appengine/browse_thread/thread/6423299aa163134d
HTTP/1.x 200 OK
Content-Type: text/x-cross-domain-policy
Expires: Fri, 11 Apr 2008 15:57:52 GMT
Cache-Control: private, max-age=0
Transfer-Encoding: chunked
Content-Encoding: gzip
Date: Fri, 11 Apr 2008 15:57:52 GMT
Server: GFE/1.3
X-Google-Netmon-Label: /bns/bx/babysitter/dasher_gfe/gfe/0/4
Through the redirect, the front end is serving something very
different. Different Content-Type, gziped, etc.
I don't have an AppEnging account, or I'd test a bit more. But that's
likely the problem right there.