testing.py 文件源码

def session_transaction(self, *args, **kwargs):
        """When used in combination with a ``with`` statement this opens a
        session transaction.  This can be used to modify the session that
        the test client uses.  Once the ``with`` block is left the session is
        stored back.

        ::

            with client.session_transaction() as session:
                session['value'] = 42

        Internally this is implemented by going through a temporary test
        request context and since session handling could depend on
        request variables this function accepts the same arguments as
        :meth:`~flask.Flask.test_request_context` which are directly
        passed through.
        """
        if self.cookie_jar is None:
            raise RuntimeError('Session transactions only make sense '
                               'with cookies enabled.')
        app = self.application
        environ_overrides = kwargs.setdefault('environ_overrides', {})
        self.cookie_jar.inject_wsgi(environ_overrides)
        outer_reqctx = _request_ctx_stack.top
        with app.test_request_context(*args, **kwargs) as c:
            sess = app.open_session(c.request)
            if sess is None:
                raise RuntimeError('Session backend did not open a session. '
                                   'Check the configuration')

            # Since we have to open a new request context for the session
            # handling we want to make sure that we hide out own context
            # from the caller.  By pushing the original request context
            # (or None) on top of this and popping it we get exactly that
            # behavior.  It's important to not use the push and pop
            # methods of the actual request context object since that would
            # mean that cleanup handlers are called
            _request_ctx_stack.push(outer_reqctx)
            try:
                yield sess
            finally:
                _request_ctx_stack.pop()

            resp = app.response_class()
            if not app.session_interface.is_null_session(sess):
                app.save_session(sess, resp)
            headers = resp.get_wsgi_headers(c.request.environ)
            self.cookie_jar.extract_wsgi(c.request.environ, headers)