Improve PageSizeSelectMixin ( transfer from RADIS)

TODO.md

@@ -87,6 +87,10 @@
 
 ## Maybe
 
+- Replace with_type_hint by Protocols
+  -- RADIS currently uses Protocols for type hints but ADIT with_type_hint for mixins
+  -- Protocols would work instead for the with_type_hint implementation in mypy
+  -- Protocols are also the official way to type hint mixins
 - New batch transfer
   -- Create new batch transfer job and allow to add tasks
   -- Add tasks manually or using a Excel file

adit/core/mixins.py

@@ -109,15 +109,22 @@ class PageSizeSelectMixin(with_type_hint(ListView)):
     which is used by this mixin for the page size.
     """
 
-    def get_context_data(self, **kwargs):
-        context = super().get_context_data(**kwargs)
+    def get(self, request: HttpRequest, *args: Any, **kwargs: Any) -> HttpResponse:
+        # Make the initial paginate_by attribute the default page size if set
+        if not hasattr(self, "paginate_by") or self.paginate_by is None:
+            self.paginate_by = 50
+
         try:
-            per_page = int(self.request.GET.get("per_page", 50))
+            per_page = int(request.GET.get("per_page", self.paginate_by))
         except ValueError:
-            per_page = 50
+            per_page = self.paginate_by
 
-        per_page = min(per_page, 1000)
-        self.paginate_by = per_page  # Used by django_tables2
+        per_page = min(per_page, 100)
+        self.paginate_by = per_page  # used by MultipleObjectMixin (and also django_tables2)
 
+        return super().get(request, *args, **kwargs)
+
+    def get_context_data(self, **kwargs):
+        context = super().get_context_data(**kwargs)
         context["page_size_select"] = PageSizeSelectForm(self.request.GET, [50, 100, 250, 500])
         return context