python - Get request body as string in Django

Question

I'm sending a POST request with JSON body to a Django server (fairly standard). On the server I need to decode this using json.loads().

The problem is how do I get the body of the request in a string format?

I have the following code currently:

body_data = {}
if request.META.get('CONTENT_TYPE', '').lower() == 'application/json' and len(request.body) > 0:
    try:
        body_data = json.loads(request.body)
    except Exception as e:
        return HttpResponseBadRequest(json.dumps({'error': 'Invalid request: {0}'.format(str(e))}), content_type="application/json")

However, this gives an error the JSON object must be str, not 'bytes'.

How do I retrieve the body of the request as a string, with the correct encoding applied?

Answer 1

The request body, request.body, is a byte string. In Python 3.0 to 3.5.x, json.loads() will only accept a unicode string, so you must decode request.body before passing it to json.loads().

body_unicode = request.body.decode('utf-8')
body_data = json.loads(body_unicode)

In Python 2, json.loads will accept a unicode string or a byte sting, so the decode step is not necessary.

When decoding the string, I think you're safe to assume 'utf-8' - I can't find a definitive source for this, but see the quote below from the jQuery docs:

Note: The W3C XMLHttpRequest specification dictates that the charset is always UTF-8; specifying another charset will not force the browser to change the encoding.

In Python 3.6, json.loads() accepts bytes or bytearrays. Therefore you shouldn't need to decode request.body (assuming it's encoded in UTF-8).