App Engine applications can be implemented using the PHP original runtime now. (see Get started with App Engine for PHP - scalable, secure and reliable on Google Cloud Platform Blog (16 May 2013).
It seems that the PHP process on Google App Engine does not have enough permissions to create folders. According to their documentation, the built-in stream handler ftp()
is not supported too.
Is the GAE file system read-only? What possibilities do we have?