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Django Singleton Model and ModelAdmin
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| from django.db import models | |
| from django.contrib import admin | |
| from django.contrib.admin.options import csrf_protect_m | |
| class SingletonModel(models.Model): | |
| class Meta: | |
| abstract = True | |
| def save(self, *args, **kwargs): | |
| self.pk = 1 | |
| super().save(*args, **kwargs) | |
| def delete(self, *args, **kwargs): | |
| pass # or return some reasonable validation/permission error. | |
| @classmethod | |
| def load(cls): | |
| try: | |
| return cls.objects.get(pk=1) | |
| except cls.DoesNotExist: | |
| raise Exception('You have to create "{}" first.'.format(cls.__name__)) | |
| class SingletonModelAdmin(admin.ModelAdmin): | |
| """ | |
| Class for SingletonModel subclasses to skip change list view and | |
| hide "Add" and "Save and add another" buttons is instance already exists. | |
| """ | |
| @csrf_protect_m | |
| def changelist_view(self, request, extra_context=None): | |
| instance = self.model.objects.first() | |
| return self.changeform_view( | |
| request=request, | |
| object_id=str(instance.id) if instance else None, | |
| extra_context=extra_context) | |
| def has_add_permission(self, request): | |
| return not self.model.objects.exists() |
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