使用Google云端存储时出错

Question

I'm trying to use Cloud Storage with App Engine. But I get the following error.

Traceback (most recent call last):
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1535, in __call__
    rv = self.handle_exception(request, response, e)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1529, in __call__
    rv = self.router.dispatch(request, response)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1278, in default_dispatcher
    return route.handler_adapter(request, response)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1102, in __call__
    return handler.dispatch()
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 572, in dispatch
    return self.handle_exception(e, self.app.debug)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 570, in dispatch
    return method(*args, **kwargs)
  File "/base/data/home/apps/s~sigmar-notes1/1.389052547617375726/main.py", line 47, in post
    real_path = os.path.join('/', bucket_name, user.user_id(), file_name)
  File "/base/data/home/runtimes/python27/python27_dist/lib/python2.7/posixpath.py", line 75, in join
    if b.startswith('/'):
AttributeError: 'NoneType' object has no attribute 'startswith'

I'm new to App Engine and I'm using code from "Python for google App Engine" by Massimiliano Pippi. Here is the code I'm using.

class MainHandler(webapp2.RequestHandler):

    def get(self):
        user = users.get_current_user()
        template_context = {}

        if user is not None:
            logout_url = users.create_logout_url(self.request.uri)
            template_context = {
                'user': user.nickname(),
                'logout_url': logout_url,
            }
            template = jinja_env.get_template('main.html')
            self.response.out.write(template.render(template_context))

        else:
            login_url = users.create_login_url(self.request.uri)
            self.redirect(login_url)

    def post(self):
        user = users.get_current_user()
        if user is None:
            self.error(401)

        bucket_name = app_identity.get_default_gcs_bucket_name()
        uploaded_file = self.request.POST.get('uploaded_file')
        file_name = getattr(uploaded_file, 'filename', None)
        file_content = getattr(uploaded_file, 'file', None)
        real_path = ''
        if file_name and file_content:
            content_t = mimetypes.guess_type(file_name)[0]
            real_path = os.path.join('/', bucket_name, user.user_id(), file_name)

            with cloudstorage.open(real_path, 'w', content_type=content_t) as f:
                f.write(file_content.read())

        self._create_note(user, file_name)

        logut_url = users.create_logout_url(self.request.uri)
        template_context = {
            'user': user.nickname(),
            'logout_url': logut_url,
            'note_title': self.request.get('title'),
            'note_content': self.request.get('content'),
        }
        self.response.out.write(self._render_template('main.html', template_context))

    def _render_template(self, template_name, context=None):
        if context is None:
            context = {}

        user = users.get_current_user()
        ancestor_key = ndb.Key("User", user.nickname())
        gry = Note.owner_query(ancestor_key)
        context['notes'] = gry.fetch()

        template = jinja_env.get_template(template_name)
        return template.render(context)

    @ndb.transactional
    def _create_note(self, user, file_name):
        note = Note(parent=ndb.Key("User", user.nickname()), title=self.request.get('title'), content=self.request.get('content'))
        note.put() 

        item_titles = self.request.get('checklist_items').split(',')
        for item_title in item_titles:
            item = CheckListItem(parent=note.key, title=item_title)
            item.put()
            note.checklist_items.append(item.key)

        if file_name:
            note.files.append(file_name)

        note.put()

Answer 1

您对os.path.join调用的参数之一是None ：

real_path = os.path.join('/', bucket_name, user.user_id(), file_name)

Answer 2

It turned out that the default bucket had not been created. I had to use the old app engine console to create it. Here is a link to the solution