Error loading the plugin list

[Xevib]

I'm executing using python flask_app/main.py and when load the plugin repo with qgis I get:

Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1836, in call
return self.wsgi_app(environ, start_response)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1820, in wsgi_app
response = self.make_response(self.handle_exception(e))
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1403, in handle_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1817, in wsgi_app
response = self.full_dispatch_request()
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1477, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1381, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1475, in full_dispatch_request
rv = self.dispatch_request()
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1461, in dispatch_request
return self.view_functionsrule.endpoint
File "/home/xbarnada/gits/qgis-plugins-xml/flask_app/main.py", line 79, in filter_xml
xml_dir = os.path.join(request.environ.get('DOCUMENT_ROOT'), 'plugins')
File "/usr/lib/python2.7/posixpath.py", line 77, in join
elif path == '' or path.endswith('/'):
AttributeError: 'NoneType' object has no attribute 'endswith'

I checked the dict request.environ and I noticed that and it don't have the DOCUMENT_ROOT key .

The content is this:
request.environ:{'wsgi.multiprocess': False, 'SERVER_SOFTWARE': 'Werkzeug/0.11.9', 'SCRIPT_NAME': '', 'REQUEST_METHOD': 'GET', 'PATH_INFO': '/plugins/plugins.xml', 'SERVER_PROTOCOL': 'HTTP/1.1', 'QUERY_STRING': 'qgis=2.18', 'werkzeug.server.shutdown': <function shutdown_server at 0x7fede16c7848>, 'CONTENT_LENGTH': '', 'HTTP_USER_AGENT': 'Mozilla/5.0 QGIS/2.18.0', 'HTTP_CONNECTION': 'Keep-Alive', 'SERVER_NAME': '0.0.0.0', 'REMOTE_PORT': 54305, 'wsgi.url_scheme': 'http', 'SERVER_PORT': '8000', 'werkzeug.request': <Request 'http://172.26.0.106:8000/plugins/plugins.xml?qgis=2.18' [GET]>, 'wsgi.input': <open file '', mode 'rb' at 0x7fede16fd420>, 'HTTP_HOST': '172.26.0.106:8000', 'wsgi.multithread': False, 'wsgi.version': (1, 0), 'wsgi.run_once': False, 'wsgi.errors': <open file '', mode 'w' at 0x7fede76f41e0>, 'REMOTE_ADDR': '172.26.0.106', 'HTTP_ACCEPT_LANGUAGE': 'ca-ES,en,*', 'CONTENT_TYPE': '', 'HTTP_ACCEPT_ENCODING': 'gzip'}

I'm using the version 0.11.1 of Flask

I don't know if its due a configuration problem