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I have a PUT request and I want to update the values of few of the params in my middleware. I know there is no way to directly access the PUT params, so I'm accessing them via request.body.

Once these values have been updated, I need to pass this request onto the view. However, if I try to do:

request.body = new_content

in my middleware, I get:

AttributeError: can't set attribute

Is there any way to update these params in the middleware and pass them on?

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sparknoob
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1 Answers1

15

request.body is defined as a property in HttpRequest class.

This is code how body property looks like:

@property
def body(self):
    if not hasattr(self, '_body'):
        if self._read_started:
            raise RawPostDataException("You cannot access body after reading from request's data stream")
        try:
            self._body = self.read()
        except IOError as e:
            six.reraise(UnreadablePostError, UnreadablePostError(*e.args), sys.exc_info()[2])
        self._stream = BytesIO(self._body)
    return self._body

The aproach that I will use there is to modify _body attribute in the process_request method. The return value here is None, because I want that Django continue processing that request through middleware until to the appropriate view.

class MidddlewareWithHttpPutRequest:
    def process_request(self, request):
        data = getattr(request, '_body', request.body)
        request._body = data + '&dummy_param=1'
        # if you call request.body here you will see that new parameter is added
        return None
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    To add a note to this: request.body will call request.read() which reads from a file-like buffer `request._stream`. I needed to "refill" this buffer as well (Django Rest Framework reads from this buffer). You can do so by `request._stream = BytesIO(body_contents)` – Jacob Valenta Apr 24 '14 at 03:55