DRF request.data has no attribute _mutable

Question

I'm using Django 2.x and Django REST framework.

I'm using django-oauth-toolkit to enable OAuth2 authentication and django-rest-auth for login and django-allauth for user registration.

I want to generate access token in the response when a user is successfully registered. For that, I'm using a custom registration view.

For that, I have created a function utils like

def generate_token(request, user):
    # Get OAuth application to use
    application_: Application = Application.objects.filter(
        client_type=Application.CLIENT_CONFIDENTIAL,
        authorization_grant_type=Application.GRANT_PASSWORD
    ).first()

    if not application_:
        raise Exception('No OAuth2 Application is setup')

    auth_data = {
        'username': user.username,
        'password': password,
        'grant_type': 'password',
        'client_id': application_.client_id,
        'client_secret': application_.client_secret
    }

    if request.data:

        mutable = request.data._mutable
        request.data._mutable = True
        request.data.update(auth_data)
        request.data._mutable = mutable

    if request.POST:
        mutable = request.POST._mutable
        request.POST._mutable = True
        request.POST.update(auth_data)
        request.POST._mutable = mutable

    return TokenView().create_token_response(request=request)

When the endpoint is hit by Postman it works fine and request.data has _mutable attribute.

But when it is hit by Angular application, it gives error

'dict' object has no attribute '_mutable'

and the error points to mutable = request.data._mutable

Why _mutable is missing for some requests?

Edit 2: Request headers

The request header sent by Postman is

Content-Type:"application/json"
Accept:"application/json, text/plain, /"
User-Agent:"PostmanRuntime/7.15.2"
Cache-Control:"no-cache"
Postman-Token:"b4461728-a6a9-48da-a4fa-3894920b5484"
Host:"api.staging.scanova.io"
Cookie:"messages="660481c3ce8c48b1884641ffdec0a3f701cdc9cf$..."; csrftoken=tNa6o6RDkEUTBti1cDJCvgV5oLG84qczgADeDfSY7hROsLP6cmhIgQKaamPQU7Xy; sessionid=r0l8kh58n8i14quyemj60ur6i59uhy1i"
Accept-Encoding:"gzip, deflate"
Content-Length:635
Connection:"keep-alive"

The request header from Angular is

Accept: application/json, text/plain, */*
Authorization: false false
Content-Type: application/json
Origin: https://localhost:4200
Referer: https://localhost:4200/auth/register
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36

Edit 3: Request type

The main view which is called from the endpoint is CreateAPIView. generate_token is called from this view which uses TokenView to generate an access token. The TokenView use Django's generic View.

What HTTP type request do you execute in angular? GET, POST etc.? — cagrias, Jul 31 '19 at 07:08
its `POST`. Updated question with the request headers in both scenario. — Anuj TBE, Jul 31 '19 at 07:12
What is the type of your ```request``` object? Django's ```HttpRequest``` or DRF's ```Request```? — cagrias, Jul 31 '19 at 07:16
Since the request is going through REST framework, its DRF's `Request`. If it would be `HttpRequest` then `request.POST` will work instead of `request.data` — Anuj TBE, Jul 31 '19 at 07:22
I mean, what type is your ```TokenView```? I'm guessing that you need to switch your if statements and edit ```if request.data``` as ```elif request.data``` because the request you are getting might be type of django's ```HttpRequest```. — cagrias, Jul 31 '19 at 07:24
But same code is working from **Postman** then why not from **Angular**? Is there something missing in the request? — Anuj TBE, Jul 31 '19 at 07:35
The only difference I can see is your ```content-type```. Can you modify your angular request so that it has ```content-type``` header exactly as ```application/json``` only? — cagrias, Jul 31 '19 at 07:38
No, even `content-type` is same in both set to `application/json`. — Anuj TBE, Jul 31 '19 at 07:40
@AnujTBE Would you print `request.META.get('CONTENT_TYPE')` on the django function and test from both postman and Angular? — Abdul Niyas P M, Jul 31 '19 at 07:41
The Postman content type is `multipart/form-data` while the Angular's is `application/json`. It seems this is the main issue. But Postman's console is saying the Content-Type header is `application/json` — Anuj TBE, Jul 31 '19 at 07:58

score 6 · Answer 1 · answered Jun 04 '20 at 08:56

For posterity (even though the question is rather old):

It seems like django/DRF treats multipart/form-data and application/json content type in a different enough way to cause issues.

So, even when using the same endpoint(viewset) and depending on whether the form is sent as multipart or app/json - request.data will be a different object.

In one case it would be a 'normal' dict while in other it would be of QueryDict type. So, in order to use the hacky _mutable on/off an additional check similar to this is needed:

...
# one can also use:
# if 'multipart/form-data' in request.META.get('CONTENT_TYPE'):
# instead of the condition below
if isinstance(request.data, QueryDict):
  auth_data = json.dumps(auth_data) # <----- QueryDict expects string values

request.POST._mutable = True # <----- mutable needs to be modified on POST and not on data
request.data.update(auth_data)
request.POST._mutable = False
...

score 1 · Answer 2 · answered Jun 25 '20 at 20:43

1

I used (request.POST._mutable = True) and this way does not work for me. then I copied request.POST in a new variable and I use the new variable in whole my code and this way work fine

answered Jun 25 '20 at 20:43

Aliakbar Hamzeh

11
1

DRF request.data has no attribute _mutable

2 Answers2