app.py 文件源码

def preprocess_request(self):
        """Called before the actual request dispatching and will
        call every as :meth:`before_request` decorated function.
        If any of these function returns a value it's handled as
        if it was the return value from the view and further
        request handling is stopped.

        This also triggers the :meth:`url_value_processor` functions before
        the actual :meth:`before_request` functions are called.
        """
        bp = _request_ctx_stack.top.request.blueprint

        funcs = self.url_value_preprocessors.get(None, ())
        if bp is not None and bp in self.url_value_preprocessors:
            funcs = chain(funcs, self.url_value_preprocessors[bp])
        for func in funcs:
            func(request.endpoint, request.view_args)

        funcs = self.before_request_funcs.get(None, ())
        if bp is not None and bp in self.before_request_funcs:
            funcs = chain(funcs, self.before_request_funcs[bp])
        for func in funcs:
            rv = func()
            if rv is not None:
                return rv