Collating snippets into derivable class

Author: rhaver

simple_history/admin.py

@@ -3,7 +3,7 @@
 from django.conf import settings
 from django.contrib import admin
 from django.contrib.admin import helpers
-from django.contrib.admin.utils import unquote
+from django.contrib.admin.utils import unquote, quote
 from django.contrib.auth import get_permission_codename
 from django.core.exceptions import PermissionDenied
 from django.shortcuts import get_object_or_404, render
@@ -286,37 +286,40 @@ def enforce_history_permissions(self):
         )
 
 
-class SimpleHistoryShowDeletedFilter(admin.SimpleListFilter):
+class SimpleHistoryWithDeletedAdmin(SimpleHistoryAdmin):
+  class SimpleHistoryShowDeletedFilter(admin.SimpleListFilter):
     title = "Entries"
     parameter_name = "entries"
 
     def lookups(self, request, model_admin):
-        return (
-            ("deleted_only", "Only Deleted"),
-        )
+      return (
+        ("deleted_only", "Only Deleted"),
+      )
 
     def queryset(self, request, queryset):
-        if self.value():
-            return queryset.model.history.filter(history_type='-').distinct()
-        return queryset
-
-
-class YourModelAdmin(SimpleHistoryAdmin):
-    def get_changelist(self, request, **kwargs):
-        def url_from_result_maker(history=False):
-            def custom_url_for_result(self, result):
-                pk = getattr(result, self.pk_attname)
-                from django.urls import reverse
-                from django.contrib.admin.utils import quote
-                route_type = 'history' if history else 'change'
-                route = f'{self.opts.app_label}_{self.opts.model_name}_{route_type}'
-                return reverse(f'admin:{route}',
-                               args=(quote(pk),),
-                               current_app=self.model_admin.admin_site.name)
-            return custom_url_for_result
-        changelist = super().get_changelist(request, **kwargs)
-        if request.GET.get('entries', None) == 'deleted_only':
-            changelist.url_for_result = url_from_result_maker(history=True)
-        else:
-            changelist.url_for_result = url_from_result_maker(history=False)
-        return changelist
+      if self.value():
+        return queryset.model.history.filter(history_type='-').distinct()
+      return queryset
+
+  def get_changelist(self, request, **kwargs):
+    def url_from_result_maker(history=False):
+      def custom_url_for_result(self, result):
+        pk = getattr(result, self.pk_attname)
+        route_type = 'history' if history else 'change'
+        route = f'{self.opts.app_label}_{self.opts.model_name}_{route_type}'
+        return reverse(f'admin:{route}',
+                       args=(quote(pk),),
+                       current_app=self.model_admin.admin_site.name)
+      return custom_url_for_result
+
+    changelist = super().get_changelist(request, **kwargs)
+    if request.GET.get('entries', None) == 'deleted_only':
+      changelist.url_for_result = url_from_result_maker(history=True)
+    else:
+      changelist.url_for_result = url_from_result_maker(history=False)
+    return changelist
+
+  def get_list_filter(self, request):
+    return [self.SimpleHistoryShowDeletedFilter] + [
+      f for f in super().get_list_filter(request)
+    ]