How can I upload and download files with graphene-

问题:

I'm currently using graphene-django v2.0 and I've absolutely no clue of how can I upload and download files like images, does anyone have an example of a query where you can download an Image and a mutation where you can upload one?

回答1:

UPLOADS

You don't need to invent your own frontend code to add a file upload to a mutation -- there are existing packages that do this already. For example, apollo-upload-client if you are using Apollo.

To receive an uploaded file on the backend, the files are going to be available in the dictionary request.FILES. So any mutation handling a file upload needs to examine info.context.FILES.items to get and save the file data. The specifics of this code are going to depend on the ultimate destination of the saved file.

(UPDATE) However, if possible I would recommend not using graphene-django to upload files because it adds a large amount of complexity on both the backend and the frontend. My team ultimately scrapped our working graphene-django file upload code and replaced it with a standard Django file upload.

DOWNLOADS

For downloads, I would recommend not using graphQL for the actual download. Instead create a Django function view that returns a HttpResponse or FileResponse and sets the Content-Disposition header. Something like

from django.http import HttpResponse

def download(request):
    ... do stuff to get file contents and file name and mime_type
    response = HttpResponse(file_contents, content_type=mime_type)
    response['Content-Disposition'] = 'attachment; filename="{}"'.format(file_name)
    return response

Then add this download path to your urls.py and to a graphQL query response. So graphQL would be used to get the download path, but actually downloading the file would be a regular Django page.