I can't get the php.ini setting for file uploads to turn on. The default setting is off as described here. In the documentation it says you can add your own php.ini file and change the default settings. My php.ini file is below and the other settings are working and show when calling phpinfo.
google_app_engine.enable_functions = "php_sapi_name, gc_enabled, phpinfo"
upload_max_filesize = 2M
max_file_uploads = 20
file_uploads = 1
Are you aware that Google App Engine only allows upload of files via specific API instead of using the language's default upload?
The current solution for handling file upload in PHP is described here: https://developers.google.com/appengine/docs/php/googlestorage/