Fix pagination keys in preserved filters querystring

README.md

@@ -36,9 +36,10 @@ pip install django-admin-inline-paginator
 
     ```
     @register(YourModel)
-    class YourModelAdmin(ModelAdmin):
+    class YourModelAdmin(InlineModelPaginated, ModelAdmin):
         fields = (...)
         inlines = (ModelWithFKAdminInline, )
+        inline_pagination_keys = (ModelWithFKAdminInline.paginated_key, )
         model = YourModel
     ```
 
@@ -64,9 +65,10 @@ pip install django-admin-inline-paginator
 
     ```
     @register(YourModel)
-    class YourModelAdmin(ModelAdmin):
+    class YourModelAdmin(InlineModelPaginated, ModelAdmin):
         fields = (...)
         inlines = (ModelWithFKAdminInline, AnotherModelWithFKInline)
+        inline_pagination_keys = (ModelWithFKAdminInline.pagination_key, AnotherModelWithFKInline.pagination_key)
         model = YourModel
     ```
 

django_admin_inline_paginator/admin.py

@@ -4,6 +4,7 @@
 from django.core.paginator import Paginator
 from django.http import HttpRequest
 from django.db.models import QuerySet
+from django.utils.http import urlencode
 
 
 class InlineChangeList:
@@ -77,3 +78,17 @@ class PaginationFormSet(PaginationFormSetBase, formset_class):
         PaginationFormSet.request = request
         PaginationFormSet.per_page = self.per_page
         return PaginationFormSet
+
+
+class InlineModelPaginated:
+    inline_pagination_keys = ('page', )
+
+    def get_preserved_filters(self, request):
+        return '&'.join(filter(None, [
+            super().get_preserved_filters(request),
+            urlencode({
+                key: request.GET.get(key)
+                for key in request.GET.keys()
+                if key in self.inline_pagination_keys
+            })
+        ]))

example/app/example/admin.py

@@ -1,5 +1,5 @@
 from django.contrib.admin import ModelAdmin, register
-from django_admin_inline_paginator.admin import TabularInlinePaginated
+from django_admin_inline_paginator.admin import TabularInlinePaginated, InlineModelPaginated
 
 from .models import Country, Region, State
 
@@ -18,7 +18,8 @@ class RegionAdminInline(TabularInlinePaginated):
 
 
 @register(Country)
-class CountryAdmin(ModelAdmin):
+class CountryAdmin(InlineModelPaginated, ModelAdmin):
     fields = ('name', 'active')
     inlines = (StateAdminInline, RegionAdminInline)
+    inline_pagination_keys = (StateAdminInline.pagination_key, RegionAdminInline.pagination_key)
     model = Country