How to access inline data in django ModelAdmin

Question

I need to process a file uploaded in a django admin form. I've added a file upload field to the form:

class ExampleInline(admin.TabularInline):
    model = OtherExample
    extra = 1
class ExampleForm(forms.ModelForm):
    filedata = forms.FileField()
    class Meta:
        model = ExampleModel
class ExampleModelAdmin(admin.ModelAdmin):
    form = ExampleForm
    inlines = [ExampleInline,]

This renders the form exactly like I want it to render. The data returned in Request is exactly what I expect.

The issue is that I want to access the contents of the inline.

class ExampleAdmin(admin.ModelAdmin):
...
def save_model(self, Request, obj, form, change):
   the_file = form.cleaned_data['filedata']
   # do amazing things to contents of file

At this point I want to reference the results of what the user selected in the inline. Whatever they picked for OtherExample.

How do I access that through the form? I would prefer not to go through the Request but am willing to do that. I'm also willing to examine save_related(self,request, form, formset, change)

Answer 1

save_related can do this, although it's called after the form is saved so you'll end up saving the object twice. You can access the object as form.instance or formset.instance.

def save_related(self, request, form, formsets, change):
    obj = form.instance
    # whatever your formset dependent logic is to change obj.filedata
    obj.save()
    super(ExampleAdmin, self).save_related(request, form, formsets, change)