oauth.py 文件源码

def start(self, url_state=None):
        """
        Starts the OAuth 2 authorization process.

        This function builds an "authorization URL".  You should redirect your
        user's browser to this URL, which will give them an opportunity to
        grant your app access to their Dropbox account.  When the user
        completes this process, they will be automatically redirected to the
        ``redirect_uri`` you passed in to the constructor.

        This function will also save a CSRF token to
        ``session[csrf_token_session_key]`` (as provided to the constructor).
        This CSRF token will be checked on :meth:`finish()` to prevent request
        forgery.

        :param str url_state: Any data that you would like to keep in the URL
            through the authorization process.  This exact value will be
            returned to you by :meth:`finish()`.
        :return: The URL for a page on Dropbox's website.  This page will let
            the user "approve" your app, which gives your app permission to
            access the user's Dropbox account. Tell the user to visit this URL
            and approve your app.
        """
        csrf_token = base64.urlsafe_b64encode(os.urandom(16)).decode('ascii')
        state = csrf_token
        if url_state is not None:
            state += "|" + url_state
        self.session[self.csrf_token_session_key] = csrf_token

        return self._get_authorize_url(self.redirect_uri, state)