decorator.py 文件源码

def required(self, price, **kwargs):
        """API route decorator to request payment for a resource.

        This function stores the resource price in a closure. It will verify
        the validity of a payment, and allow access to the resource if the
        payment is successfully accepted.
        """
        def decorator(fn):
            """Validates payment and returns the original API route."""
            @wraps(fn)
            def _fn(*fn_args, **fn_kwargs):
                # Calculate resource cost
                nonlocal price
                _price = price(request, *fn_args, **fn_kwargs) if callable(price) else price

                # Need better way to pass server url to payment methods (FIXME)
                if 'server_url' not in kwargs:
                    url = urlparse(request.url_root)
                    kwargs.update({'server_url': url.scheme + '://' + url.netloc})

                # Continue to the API view if payment is valid or price is 0
                if _price == 0:
                    return fn(*fn_args, **fn_kwargs)
                try:
                    contains_payment = self.contains_payment(_price, request.headers, **kwargs)
                except BadRequest as e:
                    return Response(e.description, BAD_REQUEST)
                if contains_payment:
                    return fn(*fn_args, **fn_kwargs)
                else:
                    # Get headers for initial 402 response
                    payment_headers = {}
                    for method in self.allowed_methods:
                        payment_headers.update(method.get_402_headers(_price, **kwargs))
                    # Accessing the .files attribute of a request
                    # drains the input stream.
                    request.files
                    raise PaymentRequiredException(payment_headers)
            return _fn
        return decorator