[BUG] Unable to retrieve media file in development

[amserra]

Hey! Thank you for your work, really appreciate it.

I'm reposting an issue I recently created on the main repo, hope you can help me.

Describe the bug
I have a model like so:

class Organization(models.Model):
    uuid = models.UUIDField(unique=True, default=uuid.uuid4, editable=False)
    logo = models.ImageField(upload_to=ORGANIZATION_LOGO_PATH)

My settings.py has the following MEDIA_URL:

MEDIA_URL = 'media/'

And my main urls.py has the following logic:

urlpatterns = [
    ...
]

# Serve static and media files in development (insecure for production!)
if settings.DEBUG is True:
    urlpatterns += static(settings.STATIC_URL, document_root=settings.STATIC_ROOT)
    urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)

As recommended by the docs.

I want my Ninja endpoint to return the full URL of the image in development so that I can use it in an external application.

This configuration works to display images on Django's templates, and in DRF, given that the request was passed to the context, like so:

serialized_data = OrganizationSerializer(organizations, many=True, context={"request": request}).data

Unfortunately, I am not being able to make it work with Ninja. The docs have no reference to this, and the only stuff I found were these two closed issues:

• ImageField missing complete URL? vitalik/django-ninja#534
• Include automatic related model lookup URL, file upload question. vitalik/django-ninja#193

Which tells me to use the full URL instead of just /media. I've tried that, setting the MEDIA_URL variable to 'http://localhost:8000/media/' or 'http://127.0.0.1:8000/media/', but it does not work, I get a 404.

Help would be appreciated!

Versions:

• Python version: [e.g. 3.10.0]
• Django version: [e.g. 5.0.3]
• Django-Ninja version: [e.g. 1.3.0]
• Pydantic version: [e.g. 2.10.6]

[pmdevita]

Is the problem with ModelSchema? Can you post an example of the API endpoint function? Additionally, if you're just getting 404s, there may an issue with how you mounted the static content. Can you get a working URL some other way?

[amserra]

Hey @pmdevita, thanks for the reply.
The model schema is very simple, just like this:

class OrganizationSchema(ModelSchema):
    class Meta:
        model = Organization
        fields = ['uuid', 'logo']

And the endpoint looks like this:

@router.get('/organizations/', response=List[OrganizationSchema])
def list_organizations(request: AuthRequest):
    return Organization.objects.all()

And the response looks like this:

[
  {
    "uuid": "acc9802e-1f7c-4d7d-8997-626e68dbf731"
    "logo": "/media/images/logos/organizations/TestOrg.png"
  },
  ...
]

As you can see, Ninja is not providing the full URL. I would expect it to return http://127.0.0.1:8000/media/images/logos/organizations/TestOrg.png.

We can do this with DRF by passing the request context to the serializer. I'm unsure what the best way to do this is in Ninja.

[amserra]

Closing this issue because I figured out a solution and posted an explanation on the main repo: vitalik/django-ninja#1417

[OtherBarry]

@amserra I'm not sure this is really a solution either.

While what you've posted solves the issue of having a MEDIA_URL setting that works with both django ninja and django, providing the full url shouldn't be dependent on a setting like that. There are many situations where the django might be supporting multiple valid base URLs, or is simply unaware at a settings level of what the base URL is.

We can do this with DRF by passing the request context to the serializer. I'm unsure what the best way to do this is in Ninja.

Pydantic supports serialisation context in the same way that DRF does, could we not just always provide the request in the context when serialising a response object?

[OtherBarry]

@pmdevita

It looks like the request is already passed as context to pydantic, so this could just be done by modifying the existing FieldFile check in DjangoGetter._convert_result into something like this:

        elif isinstance(result, FieldFile):
            if not result:
                return None
            url = result.url
            if (
                self._context is not None
                and (request := self._context.get("request")) is not None
            ):
                return request.build_absolute_uri(url)
            return url

You might want to add a setting or something to keep it backwards compatible, but otherwise the above solves this issue in a more robust manner.

LMK if you want me to put a PR up, or if this is better going in the actual ninja repo.

[pmdevita]

OK so it looks like this is primarily a development environment issue. In production, from what I've read (but please correct me if I'm wrong!), you should be setting MEDIA_URL and STATIC_URL to include your domain, with a common case being for a CDN on another domain. The workaround seems like it's fighting against what Django wants to do so I'm not positive about it.

With that in mind, I think perhaps a Django boolean setting (NINJA_ABSOLUTE_FILE_URL?) to control this could be a good idea. It seems that the use case if you want this behavior is to have it for all of your file URLs so that should be fine. I'd be interested in hearing any other opinions or perspectives on this too.

I'd be willing to take a PR for this. If you want to send it to Ninja, that's fine too.

[amserra]

Thanks for the contribution @OtherBarry!

@amserra I'm not sure this is really a solution either.

While what you've posted solves the issue of having a MEDIA_URL setting that works with both django ninja and django, providing the full url shouldn't be dependent on a setting like that. There are many situations where the django might be supporting multiple valid base URLs, or is simply unaware at a settings level of what the base URL is.

I agree with you. The solution I've posted isn't the best, but it's the only one that works with the current version (1.3.0).

If you can put up a PR with the code you posted I can review it. I believe it would be best to create here and in Ninja.

OK so it looks like this is primarily a development environment issue. In production, from what I've read (but please correct me if I'm wrong!), you should be setting MEDIA_URL and STATIC_URL to include your domain, with a common case being for a CDN on another domain. The workaround seems like it's fighting against what Django wants to do so I'm not positive about it.

@pmdevita correct!