fix #45 (Pagination does not carry filter parameters)

django_admin_search/admin.py

@@ -4,6 +4,7 @@
 from django.core.exceptions import ValidationError
 from django.db.models import Q
 from django.utils.translation import gettext_lazy as _
+from urllib.parse import urlencode
 
 from django_admin_search import utils
 
@@ -29,30 +30,51 @@ def get_queryset(self, request):
 
     def changelist_view(self, request, extra_context=None):
         """
-            Append custom form to page render
+            Append custom form and search parameters to page render
         """
         extra_context = extra_context or {}
+        advanced_search_params = {}
+
         if hasattr(self, 'search_form'):
+            original_get = request.GET.copy()
+
             self.advanced_search_fields = {}
-            self.search_form_data = self.search_form(request.GET.dict())
-            self.extract_advanced_search_terms(request.GET)
-            extra_context.update({'asf': self.search_form_data})
+            self.search_form_data = self.search_form(original_get)
+            is_form_valid = self.search_form_data.is_valid()
+            self.extract_advanced_search_terms(original_get, is_form_valid)
+
+            form_fields = self.search_form_data.fields.keys() if self.search_form_data else []
+            for key, value_list in original_get.lists():
+                if key in form_fields and self.advanced_search_fields.get(key):
+                    advanced_search_params[key] = value_list
+
+            extra_context.update({
+                'asf': self.search_form_data,
+                'advanced_search_params': urlencode(advanced_search_params, doseq=True)
+            })
+
+        response = super().changelist_view(request, extra_context=extra_context)
 
-        return super().changelist_view(request, extra_context=extra_context)
+        if hasattr(response, 'context_data'):
+            response.context_data.update(extra_context)
 
-    def extract_advanced_search_terms(self, request):
+        return response
+
+    def extract_advanced_search_terms(self, request_get, is_form_valid):
         """
-            allow to extract field values from request
+            Extract field values from the provided GET dictionary.
+            Uses the populated search_form_data to identify relevant fields.
         """
-        request._mutable = True  # pylint: disable=protected-access
+        self.advanced_search_fields = {}
 
-        if self.search_form_data is not None:
-            for key in self.search_form_data.fields.keys():
-                temp = request.pop(key, None)
-                if temp:  # there is a field but it's empty so it's useless
-                    self.advanced_search_fields[key] = temp
+        if self.search_form_data and is_form_valid:
+            for key, field in self.search_form_data.fields.items():
+                cleaned_value = self.search_form_data.cleaned_data.get(key)
 
-        request._mutable = False  # pylint: disable=protected-access
+                if cleaned_value is not None and cleaned_value != '':
+                     value_list = request_get.getlist(key)
+                     if any(v is not None and v != '' for v in value_list):
+                         self.advanced_search_fields[key] = value_list
 
     def get_request_field_value(self, field):
         """
@@ -109,3 +131,17 @@ def advanced_search_query(self, request):
             query &= self.get_field_value(field, form_field, field_value, has_field_value, request)
 
         return query
+
+    def lookup_allowed(self, lookup, value, request=None):
+        if hasattr(self, 'search_form') and self.search_form and hasattr(self.search_form, 'base_fields'):
+            for field, form_field in self.search_form.base_fields.items():
+                widget_attrs = getattr(form_field.widget, 'attrs', {})
+                base_lookup = widget_attrs.get('filter_field', field)
+                filter_method = widget_attrs.get('filter_method', '')
+
+                generated_lookup = f"{base_lookup}{filter_method}"
+
+                if lookup == generated_lookup:
+                    return True
+
+        return super().lookup_allowed(lookup, value, request)

django_admin_search/templates/admin/filter.html

@@ -0,0 +1,8 @@
+{% load i18n %}
+<h3>{% blocktranslate with filter_title=title %} By {{ filter_title }} {% endblocktranslate %}</h3>
+<ul role="list">
+{% for choice in choices %}
+  <li{% if choice.selected %} class="selected"{% endif %}>
+  <a href="{{ choice.query_string|iriencode }}{% if advanced_search_params %}&amp;{{ advanced_search_params }}{% endif %}">{{ choice.display }}</a></li>
+{% endfor %}
+</ul> 

django_admin_search/templates/admin/pagination.html

@@ -0,0 +1,24 @@
+{% load admin_list %}
+{% load i18n %}
+<div class="paginator">
+{% if pagination_required %}
+<span class="step-links">
+    {% if page_obj.has_previous %}
+        <a href="{{ page_obj.previous_page_number.querystring }}{% if advanced_search_params %}&amp;{{ advanced_search_params }}{% endif %}" class="prev">&lsaquo; {% translate "Previous" %}</a>
+    {% endif %}
+
+    <span class="current">
+        {% blocktranslate with page_number=page_obj.number total_pages=paginator.num_pages %}
+            Page {{ page_number }} of {{ total_pages }}.
+        {% endblocktranslate %}
+    </span>
+
+    {% if page_obj.has_next %}
+        <a href="{{ page_obj.next_page_number.querystring }}{% if advanced_search_params %}&amp;{{ advanced_search_params }}{% endif %}" class="next">{% translate "Next" %} &rsaquo;</a>
+    {% endif %}
+</span>
+{% endif %}
+
+{% cl_show_full_result_count %}
+
+</div>